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  • 1.
    Abrahamsson, Erik
    et al.
    Lund University, Sweden.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    A living based on breath-hold diving in the Bajau Laut2014Ingår i: Human Evolution, ISSN 0393-9375, Vol. 29, nr 1-3, s. 171-183Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sea nomads or 'sea people,' namely the 'Bajau Laut' in the Philippines, Malaysia and Indonesia are skilled divers, and many Bajau Laut make a living from freediving. Men do most of the spearfishing, but women also dive, predominantly for gathering sea food. They start to dive at an early age and spend most days of their lives on and in the sea. Our objective was to study their diving and way of life, to reveal if modern humans have the physiological potential for making a living from breath-hold diving for fishing and gathering. Bajau Laut were visited for a total of nine months, during three periods from 2010-2013, in a combined physiological and social-Anthropological study. The diving physiology studies focused on a total of 10 male divers, whose working day diving while spearfishing was logged with time-depth loggers. One group of 5 divers were engaged in shallow (5-7 m) spearfishing with an underwater working time of 60%, when diving for 2-9 h. The other group of 5 divers went to a mean depth of 10 m and had an underwater working time of 50%, when diving for 3-9 h per day. During that time, between one and eight kilograms of coral fish, blow fish, moray eels and octopuses were caught, per diver. Seafood collected by the women included clams, crustaceans, sea weed and sea cucumbers. Life among the Bajau Laut was much like it was 25 years ago, although in some areas the fish stock is diminishing, making it necessary for the Bajau Laut to spend more time in the water to obtain the same quantity of fish. It was concluded that modern humans do possess the physiological qualities necessary for making a living from hunting-gathering via breath-hold diving.

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  • 2. Andersson, J
    et al.
    Biasoletto-Tjellström, G
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Reduced pulmonary oxygen uptake during apnea in resting humans: European Underwater and Baromedical Society (EUBS) meeting Copenhagen2003Konferensbidrag (Övrigt vetenskapligt)
  • 3. Andersson, Johan
    et al.
    Linér, Mats
    Fredsted, Anne
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Cardiovascular and respiratory responses to apneas with and without face immersion in exercising humans2004Ingår i: Journal of applied physiology, ISSN 8750-7587, E-ISSN 1522-1601, Vol. 96, nr 3, s. 1005-1010Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of the diving response on alveolar gas exchange was investigated in 15 subjects. During steady-state exercise (80 W) on a cycle ergometer, the subjects performed 40-s apneas in air and 40-s apneas with face immersion in cold (10degreesC) water. Heart rate decreased and blood pressure increased during apneas, and the responses were augmented by face immersion. Oxygen uptake from the lungs decreased during apnea in air (-22% compared with eupneic control) and was further reduced during apnea with face immersion (-25% compared with eupneic control). The plasma lactate concentration increased from control (11%) after apnea in air and even more after apnea with face immersion (20%), suggesting an increased anaerobic metabolism during apneas. The lung oxygen store was depleted more slowly during apnea with face immersion because of the augmented diving response, probably including a decrease in cardiac output. Venous oxygen stores were probably reduced by the cardiovascular responses. The turnover times of these gas stores would have been prolonged, reducing their effect on the oxygen uptake in the lungs. Thus the human diving response has an oxygen-conserving effect.

  • 4. Andersson, Johan P A
    et al.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Repeated apneas do not affect the hypercapnic ventilatory response in the short term2009Ingår i: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 105, nr 4, s. 569-74Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Long-term training of breath-hold diving reduces the hypercapnic ventilatory response (HCVR), an index of the CO(2) sensitivity. The aim of the present study was to elucidate whether also short-term apnea training (repeating apneas with short intervals) reduces the HCVR, thereby being one contributing factor explaining the progressively increasing breath-holding time (BHT) with repetition of apneas. Fourteen healthy volunteers performed a series of five maximal-duration apneas with face immersion and two measurements of the HCVR, using the Read rebreathing method. The BHT increased by 43% during the series of apneas (P < 0.001). However, the slope of the HCVR test was not affected by the series of apneas, being 2.52 (SD 1.27) and 2.24 (SD 1.14) l min(-1) mmHg(-1) in the control test and in the test performed within 2 min after the last apnea of the series, respectively (NS). Thus, a change in the HCVR cannot explain the observed short-term training effect on BHT.

  • 5.
    Andersson, Johan P.A.
    et al.
    Lunds universitet.
    Biasoletto-Tjellströma, Gustaf
    Schagatay, Erika K.A
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Pulmonary gas exchange is reduced by the cardiovascular diving response in resting humans2008Ingår i: Respiratory Physiology & Neurobiology, ISSN 1569-9048, E-ISSN 1878-1519, Vol. 160, nr 3, s. 320-324Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The diving response reduces the pulmonary O2 uptake in exercising humans, but it has been debated whether this effect is present at rest. Therefore, respiratory and cardiovascular responses were recorded in 16 resting subjects, performing apnea in air and apnea with face immersion in cold water (10 ◦C). Duration of apneas were predetermined to be identical in both conditions (average: 145 s) and based on individual maximal capacity (average: 184 s). Compared to apnea in air, an augmented diving response was elicited by apnea with face immersion. The O2 uptake from the lungs was reduced compared to the resting eupneic control (4.6 ml min−1 kg−1), during apnea in air (3.6 ml min−1 kg−1) and even more so during apnea with face immersion (3.4 ml min−1 kg -1). We conclude that the cardiovascular djustments of the diving response reduces pulmonary gas exchange in resting humans, allowing longer apneas by preserving the lungs’ O2 store for use by vital organs.

  • 6.
    Andersson, Johan P.A.
    et al.
    Department of Animal Physiology, Lund University.
    Linér, Mats H.
    Lund University Hospital.
    Rünow, Elisabeth
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Diving response and arterial oxygen saturation during apnea and exercise in breath-hold divers2002Ingår i: Journal of applied physiology, ISSN 8750-7587, E-ISSN 1522-1601, Vol. 93, nr 3, s. 882-886Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study addressed the effects of apnea in air and apnea with face immersion in cold water (10°C) on the diving response and arterial oxygen saturation during dynamic exercise. Eight trained breath-hold divers performed steady-state exercise on a cycle ergometer at 100 W. During exercise, each subject performed 30-s apneas in air and 30-s apneas with face immersion. The heart rate and arterial oxygen saturation decreased and blood pressure increased during the apneas. Compared with apneas in air, apneas with face immersion augmented the heart rate reduction from 21 to 33% (P < 0.001) and the blood pressure increase from 34 to 42% (P < 0.05). The reduction in arterial oxygen saturation from eupneic control was 6.8% during apneas in air and 5.2% during apneas with face immersion (P < 0.05). The results indicate that augmentation of the diving response slows down the depletion of the lung oxygen store, possibly associated with a larger reduction in peripheral venous oxygen stores and increased anaerobiosis. This mechanism delays the fall in alveolar and arterial Po2 and, thereby, the development of hypoxia in vital organs. Accordingly, we conclude that the human diving response has an oxygen-conserving effect during exercise.

  • 7. Andersson, Johan
    et al.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik, fysik och matematik (-2008).
    Arterial oxygen desaturation during apnea in humans.1998Ingår i: Undersea & Hyperbaric Medicine, ISSN 1066-2936, Vol. 25, nr 1, s. 21-25Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We studied the effect of the human diving response, defined as bradycardia and reduced peripheral blood flow, on arterial hemoglobin desaturation. We induced a diving response of different magnitudes by using apnea in air and apnea with face immersion. Each of21 subjects performed five apneas in air and five apneas with face immersion in 10°C water. Periods of apnea in both conditions were of the same duration in any individual subject (average: 126.4 s) and the order of air and water was equally distributed among subjects. Heart rate, skin capillary blood flow, arterial blood pressure, arterial hemoglobin oxygen saturation during apneas, and end-tidal fractions of CO2 after apneas were recorded with non-invasive methods. The bradycardia and capillary blood flow reduction during apnea in air (7.8 and 37.7% change from control, respectively) were significantly potentiated by face immersion (13.6 and 55.9%, respectively). Arterial hemoglobin desaturated more during apnea in air (2.7%) compared to during apnea with face immersion (1.4%). We conclude that the potentiation of the human diving response with face immersion in cold water leads to a smaller decrease in arterial hemoglobin saturation, which may reflect an oxygen-conserving effect

  • 8. Andersson, Johan
    et al.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap (-2008).
    Diving response and apneic time in humans.1998Ingår i: Undersea & Hyperbaric Medicine, ISSN 1066-2936, Vol. 25, nr 1, s. 13-19Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of this study was to compare apneic time with the human diving response, defined as heart rate (HR) reduction and reduced skin blood flow, in groups with varying degrees of breath-hold diving experience. Apneic time and HR reduction at apneas in air and apneas with face immersion in cold water were thus recorded in nine groups. Skin capillary blood flow was recorded in six of the groups. All subjects received the same information on maximizing apneic duration, and no information about their progress during the apneas. The longest apneas and the most pronounced cardiovascular adjustments were found in the young, trained divers. It was found that apneic time was significantly correlated to HR reduction among the nine groups (r = 0.94, P < 0.001), and to skin capillary blood flow reduction among the six groups where the parameter was measured (r = 0.82, P < 0.05). The correlation between HR reduction and skin capillary blood flow reduction was also significant (r = 0.85, P < 0.05). When the difference in HR reduction and apneic time between apneas in air and apneas with face immersion were compared in the nine groups, it was found that all groups reacted with a more pronounced HR reduction during apneas with face immersion. All groups without prior breath-hold diving experience were found to perform shorter apneas with face immersion than apneas in air, or apneas of the same duration in both conditions, which has been reported in other studies. However, in all groups with diving experience, the apneic time was prolonged during apneas with face immersion. The results of this study suggest an oxygen-conserving effect of the diving response in trained apneic divers

  • 9. Andersson, Johan
    et al.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Effects of lung volume and involuntary breathing movements on the human diving response1997Ingår i: European Journal of Applied Physiology, ISSN 1439-6319, Vol. 77, nr 1/2, s. 19-24Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effects of lung volume and involuntary breathing movements on the human diving response were studied in 17 breath-hold divers. Each subject performed maximal effort apnoeas and simulated dives by apnoea and cold water face immersion, at lung volumes of 60%, 85%, and 100% of prone vital capacity (VC). Time of apnoea, blood pressure, heart rate, skin capillary blood flow, and fractions of end-expiratory CO 2 and O 2 were measured. The length of the simulated dives was the shortest at 60% of VC, probably because at this level the build up of alveolar CO 2 was fastest. Apnoeas with face immersion at 100% of VC gave a marked drop in arterial pressure during the initial 20?s, probably due to high intrathoracic pressure mechanically reducing venous return. The diving response was most pronounced at 60% of VC. We concluded that at the two larger lung volumes both mechanical factors and input from pulmonary stretch receptors influenced the bradycardia and vasoconstriction, resulting in a non-linear relationship between the breath-hold lung volume and magnitude of the diving response in the near-VC range. Furthermore, the involuntary breathing movements that appeared during the struggle phase of the apnoeas were too small to affect the diving response

  • 10. Andersson, Johan
    et al.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Gislén, Anna
    Holm, Boris
    Cardiovascular responses to cold water immersions of the forearm and face, and their relationship to apnoea2000Ingår i: European Journal of Applied Physiology, ISSN 1439-6319, Vol. 83, nr 6, s. 566-572Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Apnoea as well as cold stimulation of the face or the extremities elicits marked cardiovascular reflexes in humans. The purpose of this study was to investigate whether forearm immersion in cold water has any effect on the cardiovascular responses to face immersion and apnoea. We recorded cardiovascular responses to cold-water immersions of the forearm and face in 19 (part I) and 23 subjects (part II). The experimental protocol was divided in two parts, each part containing four tests: I1, forearm immersion during eupnoea; I2, face immersion during eupnoea; I3, forearm and face immersion during eupnoea; I4, face immersion during apnoea; II1, apnoea without immersion; II2, forearm immersion during apnoea; II3, face immersion during apnoea; and II4, forearm and face immersion during apnoea. The water temperature was 9–11 °C. Cold-water immersion of either the forearm or face was enough to elicit the most pronounced thermoregulatory vasoconstriction during both eupnoea and apnoea. During eupnoea, heart rate responses to forearm immersion (3% increase) and face immersion (9% decrease) were additive during concurrent stimulation (3% decrease). During apnoea, the heart rate responses were not affected by the forearm immersion. The oxygen-conserving diving response seems to dominate over thermoregulatory responses in the threat of asphyxia. During breathing, however, the diving response serves no purpose and does not set thermoregulatory adjustments aside

  • 11.
    Bakker, Emily
    et al.
    Norwegian Univ Sci & Technol, Dept Circulat & Med Imaging, Fac Med, KG Jebsen Ctr Exercise Med, N-7006 Trondheim, Norway..
    Engan, Harald
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. ;LHL Hlth, LHL Klinikkene Raros, Roros, Norway..
    Patrician, Alexander
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Karlsen, Trine
    Norwegian Univ Sci & Technol, Dept Circulat & Med Imaging, Fac Med, KG Jebsen Ctr Exercise Med, N-7006 Trondheim, Norway.;St Olavs Univ Hosp, Trondheim, Norway..
    Wisloff, Ulrik
    Norwegian Univ Sci & Technol, Dept Circulat & Med Imaging, Fac Med, KG Jebsen Ctr Exercise Med, N-7006 Trondheim, Norway..
    Gaustad, Svein Erik
    Norwegian Univ Sci & Technol, Dept Circulat & Med Imaging, Fac Med, KG Jebsen Ctr Exercise Med, N-7006 Trondheim, Norway..
    Acute dietary nitrate supplementation improves arterial endothelial function at high altitude: A double-blinded randomized controlled cross over study2015Ingår i: Nitric oxide, ISSN 1089-8603, E-ISSN 1089-8611, Vol. 50, s. 58-64Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Introduction: Dietary nitrate (NO3-) supplementation serves as an exogenous source of nitrite (NO3-) and nitric oxide (NO) through the NO3- NO3- NO pathway, and may improve vascular functions during normoxia. The effects of NO3- supplementation in healthy lowlanders during hypobaric hypoxia are unknown. Purpose: Determine the effect of acute oral NO3- supplementation via beetroot juice (BJ) on endothelial function (flow mediated dilation; FMD) in lowlanders at 3700 m. Methods: FMD was measured using ultrasound and Doppler in the brachial artery of 11 healthy subjects (4 females, age 25 +/- 5 yrs; height 1.8 +/- 0.1 m, weight 72 +/- 10 kg) sojourning to high altitude. In a randomized, double-blinded crossover study design, FMD was measured 3 h after drinking BJ (5.0 mmol NO3-) and placebo (PL; 0.003 mmol No-3(-)) supplementation at 3700 m, with a 24-h wash out period between tests. FMD was also measured without any BJ supplementation pre-trek at 1370 m, after 5 days at 4200 m and upon return to 1370 m after 4 weeks of altitude exposure (above 2500 m). The altitude exposure was interrupted by a decent to lower altitude where subjects spent two nights at 1370 m before returning to altitude again. Results: Ten subjects completed the NO3- supplementation. FMD (mean +/- SD) pre-trek value was 6.53 +/- 2.32% at 1370 m. At 3700 m FMD was reduced to 3.84 +/- 1.31% (p < 0.01) after PL supplementation but was normalized after receiving BJ (5.77 +/- 1.14% (p = 1.00). Eight of the subjects completed the interrupted 4-week altitude stay, and their FMD was lower at 4200 m (FMD 3.04 +/- 2.22%) and at post-altitude exposure to 1370 m (FMD 3.91 +/- 2.58%) compared to pre-trek FMD at 1370 m. Conclusion: Acute dietary NO3- supplementation may abolish altitude-induced reduction in endothelial function, and can serve as a dietary strategy to ensure peripheral vascular function in lowland subjects entering high altitude environments. (C) 2015 Elsevier Inc. All rights reserved.

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  • 12.
    Bakker, Emily
    et al.
    Norwegian Univ Sci & Technol, N-7034 Trondheim, Norway.
    Engan, Harald
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande.
    Patrician, Alexander
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Karlsen, Trine
    Norwegian Univ Sci & Technol, N-7034 Trondheim, Norway.
    Wisloff, Ulrik
    Norwegian Univ Sci & Technol, N-7034 Trondheim, Norway.
    Gaustad, Svein Erik
    Norwegian Univ Sci & Technol, N-7034 Trondheim, Norway.
    Effects Of Dietary Nitrate Supplementation On Endothelial Function At High Altitude2014Ingår i: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 46, nr 5, s. 424-424Artikel i tidskrift (Övrigt vetenskapligt)
  • 13. Björkhagen, M
    et al.
    Björkhagen, A
    Engan, Harald
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Role of group dynamics and leadership in the development of acute mountain sickness2014Konferensbidrag (Refereegranskat)
  • 14.
    Björklund, Glenn
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Pettersson, Sofia
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Performance predicting factors in prolonged exhausting exercise of varying intensity2007Ingår i: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 99, nr 4, s. 423-429Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Several endurance sports, e.g. road cycling, have a varying intensity profile during competition. At present, few laboratory tests take this intensity profile into consideration. Thus, the purpose of this study was to examine the prognostic value of heart rate (HR), lactate (La−1), potassium (K+), and respiratory exchange ratio (RER) performance at an exhausting cycling exercise with varying intensity. Eight national level cyclists performed two cycle tests each on a cycle ergometer: (1) a incremental test to establish VO2max, maximum power (W max), and lactate threshold (VO2LT), and (2) a variable intensity protocol (VIP). Exercise intensity for the VIP was based upon the VO2max obtained during the incremental test. The VIP consisted of six high intense (HI) workloads at 90% of VO2max for 3 min each, interspersed by five middle intense (MI) workloads at 70% of VO2max for 6 min each. VO2 and HR were continuously measured throughout the tests. Venous blood samples were taken before, during, and after the test. Increases in HR, La-, K+, and RER were observed when workload changed from MI to HI workload (P < 0.05). Potassium and RER decreased after transition from HI to MI workloads (P < 0.05). There was a negative correlation between time to exhaustion and decrease in La- concentration during the first MI (r = −0.714; P = 0.047). Furthermore, time to exhaustion correlated with VO2LT calculated from the ramp test (r = 0.738; P = 0.037). Our results suggest that the magnitude of decrease of La−1 between the first HI workload and the consecutive MI workload could predict performance during prolonged exercise with variable intensity

  • 15.
    Blakeson, Magdalene C.
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskaper (HOV).
    Jerome, Scott P.
    Walsh, Neil P.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskaper (HOV).
    Hanstock, Helen G.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskaper (HOV).
    Illness Incidence, Psychological Characteristics, and Sleep in Dogsled Drivers During the Iditarod Trail Sled Dog Race2022Ingår i: Wilderness & environmental medicine (Print), ISSN 1080-6032, E-ISSN 1545-1534, Vol. 33, nr 1, s. 92-96Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Introduction: Every March, dogsled drivers (mushers) compete in a 1569-km race across Alaska, involving physical exertion, mental exertion, and sleep deprivation for up to 2 wk. These factors may increase mushers’ vulnerability to illness, making them a relevant study population for acute infection risk factors. Specifically, the influence of psychological factors on illness risk during prolonged physical exertion has rarely been investigated. The aim of this study was to examine the relationship between psychological characteristics, sleep deprivation, and illness incidence in Iditarod mushers. Methods: Fourteen mushers completed 4 psychological instruments to assess state and trait anxiety, resilience and perceived stress, and self-reported upper respiratory symptoms (URS) in the month before the race. Mushers self-reported sleep duration and URS during the race. Results: State and trait anxiety, resilience, and perceived stress did not differ between mushers with and without pre- and in-race URS (P>0.05). However, all mushers who reported in-race URS had reported URS ≤9 d before the race, and the onset of symptoms during the race typically occurred shortly after a rest period. Sleep duration was higher in mushers who reported in-race URS, both before (4.9±0.3 h, P=0.016) and during illness (5.9±1.3 h, P=0.006), vs mushers without in-race URS (3.4±0.8 h). Conclusions: This study highlights recent illness, rest periods, and greater sleep requirements as potential risk factors for URS onset during a multiday endurance challenge, whereas psychological factors were not associated with URS.

  • 16.
    de Bruijn, Robert
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Richardson, Matt
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    The function of the human diving response in the immersed diver2003Ingår i: Annual Meeting of the European Underwater and Baromedical Society, Copenhagen, Denmark, 2003Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Background: Much previous research has used apneic face immersion as a model for studying the diving response and its oxygen-conserving effect, however there are few direct comparisons to apneic face immersion with the body immersed. Therefore, it is not settled if the oxygen conserving effect revealed in the dry-body model persists in the immersed diver. In this study we compared the diving response and its effect on arterial oxygen saturation between apnea in horizontal dry-body and immersed-body conditions. Methods: Twelve individually determined near-maximal apneas of the same duration were completed by 17 healthy untrained subjects at rest. Three apneas in each of four categories were performed: dry-body apnea (DA), dry-body, face-immersion apnea (DFIA), immersed-body apnea (IA), and immersed-body, face-immersion apnea (IFIA), in a weighted order. For the face and body immersions, mean water temperature (± SD) was 23.1 ±0.12oC and mean air temperature was 23.3 ±0.32oC. Heart rate and arterial haemoglobin saturation were recorded non-invasively with a pulse oximeter. Results: The diving response was similar for both the dry-body and the immersed body-categories. In all 4 categories the heart rate was reduced. The heart rate reduction in DFIA and IFIA categories was more pronounced than in the DA and IA categories. Heart rate reduction during DA and DFIA was 10% (±1.6) and 18% (±2.8) respectively (P<0.01), while heart rate reduction during IA and IFIA was 9% (±2.6) and 18% (±3.1) respectively (P<0.01). In both the DFIA and IFIA categories there was less desaturation compared to the DA and IA categories (DA vs. DFIA P<0.001, IA vs. IFIA P<0.05). Conclusion: Face immersion enhances the apneic diving response both in the dry- and immersed-body conditions, and is associated with a less pronounced arterial oxygen desaturation. We conclude that the immersed diver may benefit from an oxygen conserving diving response. This study also shows that the dry-body model can be useful for studying the diving response.

  • 17.
    de Bruijn, Robert
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Richardson, Matthew
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Haughey, Helena
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Pettersson, Sofia
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    High hemoglobin levels in divers may be a result of apnea induced EPO-production2005Ingår i: FASEB JOURNAL, 2005, s. A211-A212Konferensbidrag (Refereegranskat)
    Abstract [en]

    Oxygen storage capacity is important for apneic duration and affects performance in endurance sports. We studied if hemoglobin concentration (Hb) was different in divers compared to endurance athletes and untrained subjects and if any differences could be connected to training-induced erythropoietin (EPO) -production. We first compared Hb in 3 groups of subjects: 13 elite apneic divers (35±4 years), 13 elite cross-country skiers (20±1 years) and 23 untrained subjects (29±1 years) with similar weight and height. After 20 min of horizontal rest blood samples were drawn and analysed for Hb using standard methods. In a second experiment, we compared EPO levels before and after a series of 15 maximal apneas in air in 9 previously untrained volunteers (302 years). Apneas were spaced by 2 minutes, the last minute with hyperventilation to produce durations long enough to induce hypoxia. Values were also compared to the EPO levels of a control day without apneas. The apneic divers had higher Hb than untrained subjects (P<0.05) and skiers (P<0.01). After apnea training in untrained subjects EPO levels increased in all subjects, with a mean peak value after 3 h, where the increase was 135 % of the pre apnea value (P<0.05). No increase was observed during the same time period of the control day. We concluded that higher Hb levels in apneic divers may be a result of enhanced EPO-production due to the apnea training.

  • 18.
    de Bruijn, Robert
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Richardson, Matthew
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Haughey, Helena
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Holmberg, Hans-Christer
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Hemoglobin levels in elite divers, elite skiers and untrained humans2004Konferensbidrag (Övrigt vetenskapligt)
  • 19.
    de Bruijn, Robert
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Richardson, Matthew
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Milling, U
    Lemon, H
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Erythropoietin production as a result of repeated apneas2004Konferensbidrag (Refereegranskat)
    Abstract [en]

    Background: It has been known for decades that high altitude hypoxia will lead to increased erythropoiesis. Hypoxia in mainly the kidney results in an increased production of erythropoietin (EPO) stimulating erythropoiesis. High altitude natives display a higher haemoglobin concentration than sea level residents, which in turn increase their haemoglobin concentration as part of the adaptation to altitude. Another group of humans exposed to hypoxia is apneic divers, which may endure transient acute hypoxia, spaced by periods of normal breathing. We recently found higher haemoglobin levels in elite apneic divers, compared to groups of elite skiers and untrained subjects, suggesting that apnea training may induce erythropoiesis in humans. It is well known that diving mammals display high haemoglobin concentrations, and the beneficial effects are obvious: A larger oxygen store before diving prolongs the aerobic dive limit, and a higher haemoglobin concentration may speed up recovery after apneas and act as a buffer against acidosis during the dive. Although our group comparisons reveal a higher haemoglobin concentration in divers, it cannot be determined whether this is a training effect or genetically determined i.e. if individuals with higher concentrations of haemoglobin are more prone to take up apneic diving. Methods: To investigate if apnea training can induce EPO production, 5 previously untrained volunteers (3 men and 2 women, mean ageSD 28 5.5 years) performed 15 maximal apneas in a horizontal position in air. The apneas were grouped in 3 series of 5 apneas and spaced by 2 minutes of which 1 minute was spent slightly hyperventilating, to produce apneas sufficiently long to induce hypoxia. Series were spaced by 10 minutes resting periods. To determine EPO levels, venous blood samples were taken before apneas and directly after the last apnea series, followed by samples 1, 2, 3 and 5 hours after the apneas. Results: Mean baseline EPO before the apneas was 10.2 U/L. In all subjects EPO levels increased during the 5 hours period after the apneas. The time for EPO-peak values were different among individuals. The mean peak value occurred after 3 h, where the mean increase was 12 % of the pre apnea reference value. Conclusion: The results suggest that apnea induced intermittent hypoxia could lead to increased erythropoiesis. The evaluation of these findings in a larger group of subjects, including measurements of the individual circadian variations in EPO production, is in progress.

  • 20.
    de Bruijn, Robert
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap, teknik och matematik.
    Richardson, Matthew
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap, teknik och matematik.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap, teknik och matematik.
    Increased erythropoietin concentration after repeated apneas in humans2008Ingår i: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 102, nr 5, s. 609-613Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hypoxia-induced increases in red blood cell production have been found in both altitudeadapted populations and acclimatized lowlanders. This process is mediated by erythropoietin (EPO) released mainly by the hypoxic kidney. We have previously observed high hemoglobin concentrations in elite breath-hold divers and our aim was to investigate whether apnea-induced hypoxia could increase EPO concentration. Ten healthy volunteers performed 15 voluntary maximal duration apneas, divided into three seriesof five apneas, each series separated by 10 min of rest. Apneas within series were separated by 2 min and preceded by 1 min of hyperventilation to increase apnea duration and arterial oxygen desaturation. When EPO concentration after serial apneas was compared to baseline values, an average maximum increase of 24% was found (P<0.01). No changes in EPO concentration were observed during a control day without apnea, eliminating possible effects of a diurnal rhythm or blood loss. We therefore conclude that serial apneas increase circulating EPO concentration in humans.

  • 21.
    de Bruijn, Robert
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Richardson, Matthew
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Oxygen-conserving effect of the diving response in the immersed human2009Ingår i: Diving and hyperbaric medicine, ISSN 1833-3516, Vol. 39, nr 4, s. 193-199Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Research involving the human diving response has often simulated diving by apneic face immersion. However, no comparisons of cardiovascular responses and their oxygen- conserving function have been made between simulated diving and apneic face immersion when the body is constantly immersed as during diving. We compared the diving response and its effects on arterial oxygen saturation during apneas in horizontal dry body and immersed body positions. Both air and water temperatures were 23ºC. Twelve near-maximal apneas of the same duration were completed by 17 subjects. Four series of 3 apneas each were conducted: dry body apnea (DA), dry body, face-immersion apnea (DFIA), immersed body apnea (IA), and immersed body, face-immersion apnea (IFIA). Heart rate, skin capillary blood flow, arterial blood pressure, arterial hemoglobin saturation, lung volume and end-tidal PACO2 and PAO2 were recorded non-invasively and responses during apneas were compared among series. Cardiovascular responses showed similar patterns in all series. Face immersion led to a greater reduction in heart rate during apnea, regardless of body immersion. Both DFIA and DA resulted in a transient skin vasoconstriction, more pronounced during DFIA (p<0.001). During body immersion skin vasoconstriction was constant, and neither IA nor IFIA reduced blood flow further. Less arterial desaturation occurred after both FIA series, suggesting an oxygen-conserving effect of the more powerful diving response associated with face immersion in both body positions. We conclude that a similar oxygen-conserving diving response is triggered by apnea and face immersion during full-body immersion in cool water, as in the dry body model.

  • 22.
    Engan, Harald
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande.
    Bakker, Emily
    Norwegian Univ Sci & Technol, Trondheim, Norway..
    Patrician, Alexander
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande.
    Gaustad, SE
    Norwegian Univ Sci & Technol, Trondheim, Norway..
    Karlsen, T
    Norwegian Univ Sci & Technol, Trondheim, Norway..
    Wisløff, U
    Norwegian Univ Sci & Technol, Trondheim, Norway..
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Reductions in endothelial function during altitude exposure2014Konferensbidrag (Refereegranskat)
  • 23.
    Engan, Harald K.
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Jones, Andrew M.
    Univ Exeter, Coll Life & Environm Sci, Exeter, Devon, England.
    Ehrenberg, Fanny
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Acute dietary nitrate supplementation improves dry static apnea performance2012Ingår i: Respiratory Physiology & Neurobiology, ISSN 1569-9048, E-ISSN 1878-1519, Vol. 182, nr 2-3, s. 53-59Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Acute dietary nitrate (NO3-) supplementation has been reported to lower resting blood pressure, reduce the oxygen (O-2) cost of sub-maximal exercise, and improve exercise tolerance. Given the proposed effects of NO3- on tissue oxygenation and metabolic rate, it is possible that NO3- supplementation might enhance the duration of resting apnea. If so, this might have important applications both in medicine and sport. We investigated the effects of acute NO3- supplementation on pre-apnea blood pressure, apneic duration, and the heart rate (HR) and arterial O-2 saturation (SaO(2)) responses to sub-maximal and maximal apneas in twelve well-trained apnea divers. Subjects were assigned in a randomized, double blind, crossover design to receive 70 ml of beetroot juice (BR; containing similar to 5.0 mmol of nitrate) and placebo juice (PL; similar to 0.003 mmol of nitrate) treatments. At 2.5 h post-ingestion, the subjects completed a series of two 2-min (sub-maximal) static apneas separated by 3 min of rest, followed by a maximal effort apnea. Relative to PL, BR reduced resting mean arterial pressure by 2% (PL: 86 +/- 7 vs. BR: 84 +/- 6 mmHg; P = 0.04). The mean nadir for SaO(2) after the two sub-maximal apneas was 97.2 +/- 1.6% in PL and 98.5 +/- 0.9% in BR (P = 0.03) while the reduction in HR from baseline was not significantly different between PL and BR. Importantly, BR increased maximal apneic duration by 11% (PL: 250 +/- 58 vs. BR: 278 +/- 64 s; P = 0.04). In the longer maximal apneas in BR, the magnitude of the reductions in HR and SaO(2) were greater than in PL (P <= 0.05). The results suggest that acute dietary NO3- supplementation may increase apneic duration by reducing metabolic costs. (c) 2012 Elsevier B.V. All rights reserved.

  • 24.
    Engan, Harald K.
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Lodin-Sundström, Angelica
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Comparison of two methods potentially reducing metabolism during apnea2015Konferensbidrag (Refereegranskat)
  • 25.
    Engan, Harald K.
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande. LHL Health Röros, Norwegian Heart and Lung Patient Organization, Oslo, Norway.
    Lodin-Sundström, Angelica
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande.
    Schagatay, Fanny
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    The effect of climbing mount everest on spleen contraction and increase in hemoglobin concentration during breath holding and exercise2014Ingår i: High Altitude Medicine & Biology, ISSN 1527-0297, E-ISSN 1557-8682, Vol. 15, nr 1, s. 52-57Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Release of stored red blood cells resulting from spleen contraction improves human performance in various hypoxic situations. This study determined spleen volume resulting from two contraction-evoking stimuli: breath holding and exercise before and after altitude acclimatization during a Mount Everest ascent (8848m). Eight climbers performed the following protocol before and after the climb: 5min ambient air respiration at 1370m during rest, 20min oxygen respiration, 20min ambient air respiration at 1370m, three maximal-effort breath holds spaced by 2min, 10min ambient air respiration, 5min of cycling at 100 W, and finally 10min ambient air respiration. We measured spleen volume by ultrasound and capillary hemoglobin (HB) concentration after each exposure, and heart rate (HR) and arterial oxygen saturation (Sao2) continuously. Mean (SD) baseline spleen volume was unchanged at 213 (101) mL before and 206 (52) mL after the climb. Before the climb, spleen volume was reduced to 184 (83) mL after three breath holds, and after the climb three breath holds resulted in a spleen volume of 132 (26) mL (p=0.032). After exercise, the preclimb spleen volume was 186 (89) mL vs. 112 (389) mL) after the climb (p=0.003). Breath hold duration and cardiovascular responses were unchanged after the climb. We concluded that spleen contraction may be enhanced by altitude acclimatization, probably reflecting both the acclimatization to chronic hypoxic exposure and acute hypoxia during physical work. © Copyright 2014, Mary Ann Liebert, Inc. 2014.

  • 26.
    Engan, Harald K.
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap. Unicare Rehabilitation Norway, Oslo, Norway.
    Patrician, Alexander
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap. Centre for Heart, Lung and Vascular Health, University of British Columbia Okanagan, Kelowna, Canada.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Letter to the Editor: On the increased haemoglobin concentration and improved oxygen uptake after Spirulina supplementation2021Ingår i: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 121, nr 5, s. 1513-1514Artikel i tidskrift (Refereegranskat)
  • 27.
    Engan, Harald
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Lodin-Sundström, Angelica
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Blood lactate after deep dives in 3 disciplines of competitive apnea2010Ingår i: Proceedings from the European Underwater Baromedical Society 36th Annual Meeting Istanbul, Turkey 14-18 Sept 2010, 2010Konferensbidrag (Refereegranskat)
  • 28.
    Engan, Harald
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande.
    Lodin-Sundström, Angelica
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande.
    Schagatay, Fanny
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Enhanced blood boosting spleen contraction after climbing Mt Everest2014Konferensbidrag (Refereegranskat)
  • 29.
    Engan, Harald
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande.
    Mattiason, S
    Norwegian Univ Sci & Technol, Trondheim, Norway..
    Bakker, Emily
    Norwegian Univ Sci & Technol, Trondheim, Norway..
    Patrician, Alexander
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Effect of dietary nitrate supplementation on blood pressure in native lowlanders at altitude2014Konferensbidrag (Refereegranskat)
  • 30. Engan, Harald
    et al.
    Patrician, Alexander
    Lodin-Sundström, Angelica
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för omvårdnad. Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Johansson, Hampus
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Melin, Maja
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Spleen contraction and Hb elevation after dietary nitrate intake2020Ingår i: Journal of applied physiology, ISSN 8750-7587, E-ISSN 1522-1601, Vol. 129, nr 6, s. 1324-1329Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ingestion of dietary nitrate ([Formula: see text]) is associated with improved exercise tolerance and reduced oxygen (O2) cost of exercise, ascribed to enhanced mitochondrial efficiency, muscle contractile function, or other factors. Nitrate ingestion has also been found to attenuate the reduction in arterial oxygen saturation ([Formula: see text]) during apnea and to prolong apneic duration. The spleen serves as a dynamic blood pool expelling erythrocytes into the circulation during apnea, and [Formula: see text] and nitric oxide donors may induce vasoactive effects in the mesenteric and splanchnic circulation. Our aim was to investigate the effect of ingestion of concentrated organic [Formula: see text]-rich beetroot juice (BR) on spleen volume and spleen contraction during apnea, and the resulting hemoglobin (Hb) concentration. Eight volunteers performed two apneas of submaximal and maximal duration during prone rest ∼2.5 h after ingesting 70 mL of BR (∼5 mmol [Formula: see text]) or placebo (PL; ∼0.003 mmol [Formula: see text]), on separate days in weighted order. Heart rate and [Formula: see text] were monitored continuously and spleen diameters were measured every minute for triaxial volume calculation. Capillary Hb samples were collected at baseline and after the maximal apnea. Baseline spleen volume was reduced by 66 mL after BR ingestion (22.9%; P = 0.026) and Hb was elevated (+3.0%; P = 0.015). During apneas, spleen contraction and Hb increase were similar between BR and PL conditions (NS). The study shows that dietary [Formula: see text]reduces spleen volume at rest, resulting in increased Hb. This spleen-induced Hb elevation following [Formula: see text] ingestions represents a novel mechanism that could enhance performance in conditions involving exercise, apnea, and hypoxia.NEW & NOTEWORTHY This is the first study to examine changes of spleen volume and circulating Hb following dietary [Formula: see text] supplementation. After dietary [Formula: see text] ingestion, the spleen volume at rest was reduced and Hb was elevated. The spleen contains a dynamic red blood cell reservoir, which can be mobilized and facilitate oxygen transport during various types of physiological stress. This study has revealed an additional, previously unexplored mechanism possibly contributing to the ergogenic effects of dietary [Formula: see text].

    Ladda ner fulltext (pdf)
    fulltext
  • 31.
    Engan, Harald
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande. Norwegian Heart & Lung Patient Org, LHL Klinikkene Roros, Roros, Norway.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    "Spleen Contraction and Hemoconcentration" Regarding the Review "Hemoconcentration and Hemostasis During Acute Stress: Interacting and Independent Effects" by Austin et al. 20112015Ingår i: Annals of Behavioral Medicine, ISSN 0883-6612, E-ISSN 1532-4796, Vol. 49, nr 4, s. 634-635Artikel i tidskrift (Refereegranskat)
    Ladda ner fulltext (pdf)
    fulltext
  • 32.
    Engan, Harald
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande. Department of Human Movement Science, Faculty of Social Sciences and Technology Management, NTNU, Trondheim, Norway.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande.
    Lodin-Sundström, Angelica
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande.
    Richardson, Matt
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande.
    Beekvelt, Mireille
    Department of Human Movement Science, Faculty of Social Sciences and Technology Management, NTNU, Trondheim, Norway.
    Effects of two weeks of daily apnea training on diving response, spleen contraction, and erythropoiesis in novel subjects.2013Ingår i: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 23, nr 3, s. 340-348Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Three potentially protective responses to hypoxia have been reported to be enhanced in divers: (1) the diving response, (2) the blood-boosting spleen contraction, and (3) a long-term enhancement of hemoglobin concentration (Hb). Longitudinal studies, however, have been lacking except concerning the diving response. Ten untrained subjects followed a 2-week training program with 10 maximal effort apneas per day, with pre- and posttraining measurements during three maximal duration apneas, and an additional post-training series when the apneic duration was kept identical to that before training. Cardiorespiratory parameters and venous blood samples were collected across tests, and spleen diameters were measured via ultrasound imaging. Maximal apneic duration increased by 44 s (P < 0.05). Diving bradycardia developed 3 s earlier and was more pronounced after training (P < 0.05). Spleen contraction during apneas was similar during all tests. The arterial hemoglobin desaturation (SaO(2)) nadir after apnea was 84% pretraining and 89% after the duration-mimicked apneas post-training (P < 0.05), while it was 72% (P < 0.05) after maximal apneas post-training. Baseline Hb remained unchanged after training, but reticulocyte count increased by 15% (P < 0.05). We concluded that the attenuated SaO(2) decrease during mimic apneas was due mainly to the earlier and more pronounced diving bradycardia, as no enhancement of spleen contraction or Hb had occurred. Increased reticulocyte count suggests augmented erythropoiesis.

  • 33.
    Fahlman, Andreas
    et al.
    Department of Life Sciences Texas A&M- Corpus Christi 6300 Ocean Dr Unit 5892.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Man's place among the diving mammals2014Ingår i: Human Evolution, ISSN 0393-9375, Vol. 29, nr 1-3, s. 47-66Artikel i tidskrift (Refereegranskat)
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  • 34. Fernández, FA
    et al.
    Patrician, Alexander
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Lodin-Sundström, Angelica
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Predicting static and dynamic apnea performance in elite divers using a 2-minute static apnea test2015Konferensbidrag (Refereegranskat)
  • 35.
    Fernández, Fran de Asís
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap. Universidad Autónoma de Madrid, Madrid, Spain.
    Rodríguez-Zamora, Lara
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap. Örebro University, Örebro.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Hook Breathing Facilitates SaO2 Recovery After Deep Dives in Freedivers With Slow Recovery2019Ingår i: Frontiers in Physiology, E-ISSN 1664-042X, Vol. 10, s. 1-8, artikel-id 1076Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To facilitate recovery from hypoxia, many freedivers use a breathing method called “hook breathing” (HB) after diving, involving an interrupted exhale to build up intrapulmonary pressure. Some divers experience a delay in recovery of arterial oxygen saturation (SaO2) after diving, interpreted as symptoms of mild pulmonary edema, and facilitated recovery may be especially important in this group to avoid hypoxic “blackout.” We examined the influence of HB on recovery of SaO2 in freedivers with slow recovery (SR) and fast recovery (FR) of SaO2 after deep “free immersion” (FIM) apnea dives to 30 m depth. Twenty-two male freedivers, with a mean (SD) personal best in the discipline FIM of 57(26) m, performed two 30 m deep dives, one followed by HB and one using normal breathing (NB) during recovery, at different days and weighted order. SaO2 and heart rate (HR) were measured via pulse oximetry during recovery. The SR group (n = 5) had a faster SaO2 recovery using HB, while the FR group (n = 17) showed no difference between breathing techniques. At 105 s, the SR group reached a mean (SD) SaO2 of 95(5)% using HB, while using NB, their SaO2 was 87(5)% (p < 0.05), and 105–120 s after surfacing SaO2 was higher with HB (p < 0.05). In SR subjects, the average time needed to reach 95% SaO2 with HB was 60 s, while it was 120 s at NB (p < 0.05). HR was similar in the SR group, while it was initially elevated at HB in the FR group (p < 0.05). We conclude that HB efficiently increases SaO2 recovery in SR individuals, but not in the FR group. The proposed mechanism is that increased pulmonary pressure with HB will reverse any pulmonary edema and facilitate oxygen uptake in divers with delayed recovery.

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  • 36.
    Havnes, Marianne B
    et al.
    NTNU, Trondheim Norway.
    Lodin-Sundström, Angelica
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Rasdal, Kim Vidar
    NTNU, Trondheim Norway.
    Brubakk, Alf O
    NTNU, Trondheim Norway.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Bubbles after deep breath-hold dives in competition2010Ingår i: Proceedings from the European Underwater Baromedical Society 36th Annual Meeting Istanbul, Turkey 14-18 Sept 2010, 2010Konferensbidrag (Refereegranskat)
  • 37. Holm, Boris
    et al.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Andersson, Johan
    A possible physiological role of the face as a thermosensor in an ancient water ape and in present day man1999Ingår i: Perspectives in Human Biology, Vol. 4, s. 41-46Artikel i tidskrift (Refereegranskat)
  • 38. Holm, Boris
    et al.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Kobayashi, Toshio
    Masuda, Atsuko
    Ohdaira, Tetsuro
    Honda, Yoshiyuki
    Cardiovascular Change in Elderly Male Breath-hold Divers (Ama) and their Socio-economical Background at Chikura in Japan.1998Ingår i: Applied Human Science;Journal of Physiological Anthropology, ISSN 1341-3473, Vol. 17, nr 5, s. 181-187Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Ama have existed for more than 2000 years in Japan and Korea. They have been diving for seaweed and molluscs. Their traditional way of fishing, with goggles or a mask, but without a wetsuit, is still practised as a result of laws against overfishing. We investigated cardiovascular diving responses, expressed as heart rate (HR) reduction, peripheral vasoconstriction indicated by skin blood flow (SkBF) and mean arterial blood pressure (MAP) during breath-hold face immersion in a group of eight elderly male Ama at Chikura, Japan. Their data were compared to those from three other groups: a) elderly non-divers; b) young divers and c) young non-divers. Our previous studies have shown that young divers show a more pronounced bradycardia than young non-divers. The present study of elderly Ama and elderly non-divers was performed to investigate if this difference persists in old age. We found that, in spite of many years of diving experience, HR reduction of the elderly professional divers observed during face immersion did not differ from that of elderly non-divers, but it was much less pronounced than in the two younger groups. We conclude that even if a well-developed diving response at young age has been reduced to the level of non-divers, the Ama are still able to continue their work of diving in old age. Ama that has been a traditionally female occupation, is mostly practised by men at Chikura today. No young have been recruited for this profession. Therefore, the present Ama are senior and the traditional breath-hold diving will probably cease to exist in the near future. The probable reasons for these changes are discussed

  • 39.
    Holmström, Pontus
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Bird, Jordan D.
    Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Alberta, Canada.
    Thrall, Scott F.
    Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Alberta, Canada.
    Kalker, Ann
    Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Alberta, Canada; Radboud University, Nijmegen, Netherlands.
    Herrington, Brittney A.
    Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Alberta, Canada.
    Soriano, Jan E.
    Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Alberta, Canada.
    Mann, Leah M.
    Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Alberta, Canada.
    Rampuri, Zahrah H.
    Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Alberta, Canada.
    Brutsaert, Tom
    Department of Exercise Science, Syracuse University, Syracuse, NY, United States.
    Karlsson, Øyvind
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Sherpa, Mingma T.
    Kunde Hospital, Khunde, Solukhumbu, Nepal.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Day, Trevor A.
    Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Alberta, Canada.
    The effects of high altitude ascent on splenic contraction and the diving response during voluntary apnea2021Ingår i: Experimental Physiology, ISSN 0958-0670, E-ISSN 1469-445X, Vol. 106, nr 1, s. 160-174Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Voluntary apnea causes splenic contraction and reductions in heart rate (HR; bradycardia), and subsequent transient increases in hemoglobin concentration ([Hb]). Ascent to high altitude (HA) induces systemic hypoxia and reductions in oxygen saturation (SpO2 ), which may cause tonic splenic contraction, which may contribute to hematological acclimatization associated with HA ascent. We measured resting cardiorespiratory variables (HR, SpO2 , [Hb]) and resting splenic volume (via ultrasound) during incremental ascent from 1400 m (day 0), to 3440 m (day 3), 4240 m (day 7), and 5160 m (day 10) in non-acclimatized native lowlanders during assent to HA in the Nepal Himalaya. In addition, apnea-induced responses in HR, SpO2 and splenic volume were measured before and after two separate voluntary maximal apneas (A1-A2) at 1400 m, 3440 m and 4240 m. Resting spleen volume decreased -14.3% (-15.2 mL)/1000 m with ascent, from 140±41 mL (1400 m), to 108±28 mL (3440 m; P > 0.99), 94±22 mL (4240 m; P = 0.009) and 84±28 mL (5160 m; P = 0.029), with concomitant increases in [Hb] from 125±18.3 g/L (1400 m) to 128±10.4 g/L (3440 m), 138.8±12.7 g/L (4240 m) and 157.5±8 g/L (5160 m; P = 0.021). Apnea-induced splenic contraction was 50±15 mL (1400 m), 44±17 mL (3440 m; P > 0.99) and 26±8 mL (4240 m; P = 0.002), but was not consistently associated with increases in [Hb]. The apnea-induced bradycardia was more pronounced at 3440 m (A1:P = 0.04; A2:P = 0.094) and at 4240 m (A1:P = 0.037 A2:P = 0.006) compared to values at 1400 m. We conclude that hypoxia-induced splenic contraction at rest (a) may contribute to restoring arterial oxygen content through its [Hb]-enhancing contractile function and (b) eliminates further apnea-induced [Hb] increases in hypoxia. We suggest that tonic splenic contraction may contribute to hematological acclimatization early in HA ascent in humans.

  • 40.
    Holmström, Pontus K.
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskaper (HOV). Syracuse University, Syracuse, NY, United States.
    Harman, T. S.
    Kalker, A.
    Steiner, B.
    Hawkins, E.
    Jorgensen, K. C.
    Zhu, K. T.
    Kunwar, A. J.
    Thakur, N.
    Dhungel, S.
    Sherpa, N.
    Day, T. A.
    Schagatay, Erika K.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskaper (HOV).
    Bigham, A. W.
    Brutsaert, T. D.
    Differential splenic responses to hyperoxic breathing at high altitude in Sherpa and lowlanders2024Ingår i: Experimental Physiology, ISSN 0958-0670, E-ISSN 1469-445X, Vol. 109, nr 4, s. 535-548Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The human spleen contracts in response to stress-induced catecholamine secretion, resulting in a temporary rise in haemoglobin concentration ([Hb]). Recent findings highlighted enhanced splenic response to exercise at high altitude in Sherpa, possibly due to a blunted splenic response to hypoxia. To explore the potential blunted splenic contraction in Sherpas at high altitude, we examined changes in spleen volume during hyperoxic breathing, comparing acclimatized Sherpa with acclimatized individuals of lowland ancestry. Our study included 14 non-Sherpa (7 female) residing at altitude for a mean continuous duration of 3 months and 46 Sherpa (24 female) with an average of 4 years altitude exposure. Participants underwent a hyperoxic breathing test at altitude (4300 m; barrometric pressure = ∼430 torr; (Formula presented.) = ∼90 torr). Throughout the test, we measured spleen volume using ultrasonography and monitored oxygen saturation ((Formula presented.)). During rest, Sherpa exhibited larger spleens (226 ± 70 mL) compared to non-Sherpa (165 ± 34 mL; P < 0.001; effect size (ES) = 0.95, 95% CI: 0.3–1.6). In response to hyperoxia, non-Sherpa demonstrated 22 ± 12% increase in spleen size (35 ± 17 mL, 95% CI: 20.7–48.9; P < 0.001; ES = 1.8, 95% CI: 0.93–2.66), while spleen size remained unchanged in Sherpa (−2 ± 13 mL, 95% CI: −2.4 to 7.3; P = 0.640; ES = 0.18, 95% CI: −0.10 to 0.47). Our findings suggest that Sherpa and non-Sherpas of lowland ancestry exhibit distinct variations in spleen volume during hyperoxia at high altitude, potentially indicating two distinct splenic functions. In Sherpa, this phenomenon may signify a diminished splenic response to altitude-related hypoxia at rest, potentially contributing to enhanced splenic contractions during physical stress. Conversely, non-Sherpa experienced a transient increase in spleen size during hyperoxia, indicating an active tonic contraction, which may influence early altitude acclimatization in lowlanders by raising [Hb]. 

  • 41.
    Holmström, Pontus K.
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Karlsson, Øyvind
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Lindblom, Hampus
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    McGawley, Kerry
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Schagatay, Erika K.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Enhanced splenic volume and contraction in elite endurance athletes2021Ingår i: Journal of applied physiology, ISSN 8750-7587, E-ISSN 1522-1601, Vol. 131, nr 2, s. 474-486Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Splenic contraction, which leads to ejection of stored erythrocytes, is greater in athletes involved in regular freediving or high-altitude activities. As this response facilitates oxygen-carrying capacity, similar characteristics may be expected of elite endurance athletes. Therefore, our aims were to compare resting and apnea-induced splenic volume in endurance athletes and untrained individuals, and to assess the athletes' exercise-induced splenic volume. Twelve elite biathletes (7 women) and 12 controls (6 women) performed a maximal effort apnea in a seated position. In addition, the biathletes completed a maximal roller-skiing time trial. Splenic dimensions were measured by ultrasonic imaging for subsequent volume calculations, whereas Hb was analyzed from capillary blood samples and cardiorespiratory variables were monitored continuously. Baseline splenic volume was larger in the biathletes (214 +/- 56 mL) compared with controls (157 +/- 39 mL, P = 0.008) and apnea-induced splenic contraction was also greater in the biathletes (46 +/- 20 mL vs. 30 +/- 16 mL, P = 0.035). Hb increased immediately after apnea in the biathletes (4.5 +/- 4.8%, P = 0.029) but not in the controls (-0.7 +/- 3.1%, P = 0.999). Increases in exercise-induced splenic contraction (P = 0.008) and Hb (P = 0.001) were greater compared with the apnea-induced responses among the athletes. Baseline splenic volume tended to be correlated with <(V)over dot>o(2max) (r= 0.584, P = 0.059). We conclude that elite biathletes have greater splenic volume with a greater ability to contract and elevate Hb compared with untrained individuals. These characteristics may transiently enhance O-2-carrying capacity and possibly increase O-2 uptake, thereby helping biathletes to cope with high intermittent O-2 demands and severe O-2 deficits that occur during biathlon training and competition. NEW & NOTEWORTHY This study demonstrates that elite biathletes have larger splenic volume, apnea-induced splenic contraction, and Hb elevation compared with untrained individuals, which is likely functional to cope with high O-2 demands and substantial O-2 deficits. We believe that enhanced splenic contraction may be of importance during competitions involving crosscountry skiing, to regulate circulating Hb and enhance O-2-carrying capacity, which may protect Ca-O2, and increase O-2 uptake.

  • 42.
    Holmström, Pontus
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Mulder, Eric
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Lodin-Sundström, Angelica
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för omvårdnad.
    Limbu, Prakash
    Nepalese Army Inst Hlth Sci, Kathmandu, Nepal.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    The Magnitude of Diving Bradycardia During Apnea at Low-Altitude Reveals Tolerance to High Altitude Hypoxia2019Ingår i: Frontiers in Physiology, E-ISSN 1664-042X, Vol. 10, s. 1-12, artikel-id 1075Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Acute mountain sickness (AMS) is a potentially life-threatening illness that may develop during exposure to hypoxia at high altitude (HA). Susceptibility to AMS is highly individual, and the ability to predict it is limited. Apneic diving also induces hypoxia, and we aimed to investigate whether protective physiological responses, i.e., the cardiovascular diving response and spleen contraction, induced during apnea at low-altitude could predict individual susceptibility to AMS. Eighteen participants (eight females) performed three static apneas in air, the first at a fixed limit of 60 s (A1) and two of maximal duration (A2-A3), spaced by 2 min, while SaO(2), heart rate (HR) and spleen volume were measured continuously. Tests were conducted in Kathmandu (1470 m) before a 14 day trek to mount Everest Base Camp (5360 m). During the trek, participants reported AMS symptoms daily using the Lake Louise Questionnaire (LLQ). The apnea-induced HR-reduction (diving bradycardia) was negatively correlated with the accumulated LLQ score in A1 (r(s) = -0.628, p= 0.005) and A3 (r(s) = -0.488, p = 0.040) and positively correlated with SaO(2) at 4410 m (A1: r = 0.655, p = 0.003; A2: r = 0.471, p = 0.049; A3: r = 0.635, p = 0.005). Baseline spleen volume correlated negatively with LLQ score (r(s) = -0.479, p = 0.044), but no correlation was found between apnea-induced spleen volume reduction with LLQ score (r(s) = 0.350, p = 0.155). The association between the diving bradycardia and spleen size with AMS symptoms suggests links between physiological responses to HA and apnea. Measuring individual responses to apnea at sea-level could provide means to predict AMS susceptibility prior to ascent.

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  • 43.
    Holmström, Pontus
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Mulder, Eric
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Starfelt, Victor
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Lodin-Sundström, Angelica
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för omvårdnad. Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Spleen Size and Function in Sherpa Living High, Sherpa Living Low and Nepalese Lowlanders2020Ingår i: Frontiers in Physiology, E-ISSN 1664-042X, Vol. 11, artikel-id 647Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    High-altitude (HA) natives have evolved some beneficial responses leading to superior work capacity at HA compared to native lowlanders. Our aim was to study two responses potentially protective against hypoxia: the spleen contraction elevating hemoglobin concentration (Hb) and the cardiovascular diving response in Sherpa highlanders, compared to lowlanders. Male participants were recruited from three groups: (1) 21 Sherpa living at HA (SH); (2) seven Sherpa living at low altitude (SL); and (3) ten native Nepalese lowlanders (NL). They performed three apneas spaced by a two-min rest at low altitude (1370 m). Their peripheral oxygen saturation (SpO(2)), heart rate (HR), and spleen volume were measured across the apnea protocol. Spleen volume at rest was 198 +/- 56 mL in SH and 159 +/- 35 mL in SL (p= 0.047). The spleen was larger in Sherpa groups compared to the 129 +/- 22 mL in NL (p< 0.001 compared to SH;p= 0.046 compared to SL). Spleen contraction occurred in all groups during apnea, but it was greater in Sherpa groups compared to NL (p< 0.001). HR was lower in Sherpa groups compared to NL both during rest (SL:p< 0.001; SH:p= 0.003) and during maximal apneas (SL:p< 0.001; SH:p= 0.06). The apnea-induced HR reduction was 8 +/- 8% in SH, 10 +/- 4% in SL (NS), and 18 +/- 6% in NL (SH:p= 0.005; SL:p= 0.021 compared to NL). Resting SpO(2)was similar in all groups. The progressively decreasing baseline spleen size across SH, SL, and NL suggests a role of the spleen at HA and further that both genetic predisposition and environmental exposure determine human spleen size. The similar HR responses of SH and SL suggest that a genetic component is involved in determining the cardiovascular diving response.

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  • 44.
    Holmström, Pontus
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskaper (HOV).
    Pernett, Frank
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskaper (HOV).
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskaper (HOV).
    Test–retest reliability of splenic volume assessment by ultrasonography2022Ingår i: Scientific Reports, E-ISSN 2045-2322, Vol. 12, nr 1, artikel-id 18976Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    While MRI and CT are the gold standards for assessments of splenic size in clinical settings, ultrasonography is particularly suited due to its portability, cost efficiency and easy utilization. However, ultrasonography is associated with subjective assessment, potentially resulting in increased variation. We used a test–retest design aiming to determine the reliability of splenic measurements assessed by ultrasonography during apnea. In addition, we compared reliability between different equations for volume calculations: Koga, Prolate ellipsoid and Pilström. Twelve healthy participants (6 women) performed two tests separated by 15 min, comprising a maximal voluntary apnea in a seated position. Splenic dimensions were measured via ultrasonography for 5 min before and immediately following apnea. Resting splenic volume displayed high test–retest reliability between tests (Pilström: 157 ± 39 mL vs 156 ± 34 mL, p = .651, ICC = .970, p < .001, CV = 2.98 ± 0.1%; Prolate ellipsoid: 154 ± 37 mL vs 144 ± 43 mL, p = .122, ICC = .942, p < .001, CV = 5.47 ± 0.3%; Koga: 142 ± 37 mL vs 140 ± 59 mL, p = .845, ICC = .859, p < .001, CV = 9.72 ± 1.4%). Apnea-induced volumes displayed similar reliability (127 ± 29 mL vs 129 ± 28 mL, p = .359, ICC = .967, p < .001, CV = 3.14 ± 3.1%). Reliability was also high between equations (Pilström vs Prolate ellipsoid: ICC = .818, p < .001, CV = 7.33 ± 0.3%, bias =  − 3.1 mL, LoA =  − 46.9 to 40.7 mL; Pilström vs Koga: ICC = .618, p < .01, CV = 11.83 ± 1.1%, bias =  − 14.8 mL, LoA =  − 76.9 to 47.3 mL). We conclude that splenic ultrasonographic measurements have practical applications during laboratory and field-based research as a reliable method detecting splenic volume change consistently between repeated tests. The Pilström equation displayed similar reliability compared to the prolate ellipsoid formula and slightly higher compared to the Koga formula and may be particularly useful to account for individual differences in splenic dimensions.

  • 45.
    Johansson, Hampus
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Engan, Harald K.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Melin, Maja
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Patrician, Alexander
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Lodin-Sundström, Angelica
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    No effect of dietary nitrate on the human diving response in dry and wet apneas2015Konferensbidrag (Refereegranskat)
  • 46.
    Johansson, O
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande.
    Patrician, Alexander
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande.
    Wisniewski, Sarah
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Spirometry during ascent to altitude and its correlation to acute mountain sickness2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Easily measurable variables capable of predicting altitude sickness, before symptom onset, would be beneficial for those requiring slower ascent or even medical attention. Unfortunately few such reliable factors exist. Our objective was to test respiratory function during ascent in the Nepali Himalaya, to see if any correlations with altitude sickness, expressed by Lake Louis scores, could be identified. Eleven healthy subjects (six male and five female, mean(SD) age 26(9.3) years) travelled from 1370m to 4200m, and spent 9 days at or above this altitude. Variables of lung function, including vital capacity, forced expiratory volume over one second (FEV1) and peak expiratory flow were measured using a portable spirometer every-other morning before breakfast in the standing position. Subjects also completed the Lake Louis self-assessment questionnaire daily. Mean(SD) vital capacity and FEV1 decreased from 5.3(1.4) L and 4.5(0.9) L at 1370m to 4.8(1.4) L and 4.2(1.0) L at 4200m, respectively (p<0.05), but did not correlate to Lake Louis scores. Mean(SD) peak expiratory flow was 9.4(2.3) L/s at 1370m and did not change during ascent. However once at 4200m it increased from 9.2(2.7) L/s to 9.6(2.4) L/s following the stay at altitude (p<0.05). Interestingly, an absolute change in peak expiratory flow at 4200m compared to 1370m, showed a high correlation to Lake Louis scores at 3700m and 4200m (r= -0.971; p<0.001). We conclude that peak expiratory flow values were closely related to signs of altitude sickness, and should be explored further for determining their predictive value.

  • 47.
    Johansson, Orio
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Lung-packing and stretching increases vital capacity in recreational freedivers2012Ingår i: The European respiratory journal. Supplement, ISSN 0904-1850, Vol. 40, nr Supplement 56, s. 149s-Artikel i tidskrift (Refereegranskat)
  • 48.
    Johansson, Orio
    et al.
    Lund University, Sweden.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Sara Campbell, World Champion in Deep Diving After 9 Months of Training – How Is This Possible?2014Ingår i: Human Evolution, ISSN 0393-9375, Vol. 29, nr 1-3, s. 67-73Artikel i tidskrift (Refereegranskat)
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  • 49.
    Laaksonen, Marko
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Pettersson, Sofia
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Performance predicting factors during prolonged non-steady state cycling2006Ingår i: Book of Abstracts of the 11th Annual Congress of the European College of Sport Science in Lausanne, Switzerland from 5-8 July 2006, 2006Konferensbidrag (Refereegranskat)
  • 50.
    Lindblom, Hampus
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskaper (HOV).
    Pernett, Frank
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskaper (HOV).
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskaper (HOV).
    Holmström, Pontus
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskaper (HOV).
    Effect of exercise intensity and apnea on splenic contraction and hemoglobin increase in well-trained cross-country skiers2024Ingår i: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 124, nr 7, s. 2057-2067Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The human spleen acts as a reservoir for red blood cells, which is mobilized into the systemic circulation during various conditions such as hypoxia and physical exertion. Cross-country (XC) skiers, renowned for their exceptional aerobic capacity, are regularly exposed to high-intensity exercise and local oxygen deficits. We investigated a putative dose-dependent relationship between splenic contraction and concomitant hemoglobin concentration ([Hb]) elevation across four exercise intensities in well-trained XC skiers. Fourteen male XC skiers voluntarily participated in a 2-day protocol, encompassing a serial apnea test and a VO2max test (day 1), followed by three submaximal exercise intensities on a roller skiing treadmill corresponding to 55, 70, and 85% of VO2max (day 2). Spleen volume was measured via ultrasonic imaging, and venous blood samples were used to determine [Hb] levels. Baseline spleen volume was similar (266(35) mL) for all conditions (NS). Notably, all conditions induced significant splenic contractions and transient [Hb] elevations. The VO2max test exhibited the most pronounced splenic contraction (35.8%, p < 0.001) and a [Hb] increase of 8.1%, while the 85% exercise intensity led to 27.1% contraction and the greatest [Hb] increase (8.3%, < 0.001) compared to baseline. The apnea test induced relatively smaller responses (splenic contraction: 20.4%, [Hb] = 3.3%, p < 0.001), akin to the response observed at the 70% exercise intensity (splenic contraction = 23%, [Hb] = 6.4%, p < 0,001) and 55% (splenic contraction = 20.0%, [Hb] = 4.8%, p < 0.001). This study shows a discernible dose-dependent relationship between splenic contraction and [Hb] increase with levels of exercise, effectively distinguishing between submaximal and maximal exercise intensity.

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