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  • 1.
    de Bruijn, Robert
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Richardson, Matt
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Schagatay, Erika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    The function of the human diving response in the immersed diver2003In: Annual Meeting of the European Underwater and Baromedical Society, Copenhagen, Denmark, 2003Conference paper (Other scientific)
    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.

  • 2.
    de Bruijn, Robert
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Richardson, Matthew
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Haughey, Helena
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Björklund, Glenn
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Pettersson, Sofia
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Schagatay, Erika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    High hemoglobin levels in divers may be a result of apnea induced EPO-production2005In: FASEB JOURNAL, 2005, p. A211-A212Conference paper (Refereed)
    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.

  • 3.
    de Bruijn, Robert
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Richardson, Matthew
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Haughey, Helena
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Holmberg, Hans-Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Björklund, Glenn
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Schagatay, Erika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Hemoglobin levels in elite divers, elite skiers and untrained humans2004Conference paper (Other academic)
  • 4.
    de Bruijn, Robert
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Richardson, Matthew
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Milling, U
    Lemon, H
    Schagatay, Erika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Erythropoietin production as a result of repeated apneas2004Conference paper (Refereed)
    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.

  • 5.
    de Bruijn, Robert
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Richardson, Matthew
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Schagatay, Erika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Increased erythropoietin concentration after repeated apneas in humans2008In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 102, no 5, p. 609-613Article in journal (Refereed)
    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.

  • 6.
    de Bruijn, Robert
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Richardson, Matthew
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Schagatay, Erika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Oxygen-conserving effect of the diving response in the immersed human2009In: Diving and hyperbaric medicine, ISSN 1833-3516, Vol. 39, no 4, p. 193-199Article in journal (Refereed)
    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.

  • 7.
    Engan, Harald
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Ecotechnology and Sustainable Building Engineering. Department of Human Movement Science, Faculty of Social Sciences and Technology Management, NTNU, Trondheim, Norway.
    Schagatay, Erika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Ecotechnology and Sustainable Building Engineering.
    Lodin-Sundström, Angelica
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Ecotechnology and Sustainable Building Engineering.
    Richardson, Matt
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Ecotechnology and Sustainable Building Engineering.
    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.2013In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 23, no 3, p. 340-348Article in journal (Refereed)
    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.

  • 8. Lodin-Sundström, Angelica
    et al.
    Engan, H
    Richarson, Matt
    Schagatay, Erika
    Oxygen conservation by the diving response improved after 2 weeks of apnea training2009In: 14th Annual Congress of the ECSS in Oslo, Norway 24-27 June 2009, 2009Conference paper (Refereed)
  • 9.
    Lodin-Sundström, Angelica
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Richardson, Matt
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Schagatay, Erika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Biphasic spleen contraction during apnea in divers suggests chemoreceptor input2009In: Abstract EUBS Aberdeen, UK, 25-28 Aug, 2009., 2009Conference paper (Refereed)
  • 10.
    Lodin-Sundström, Angelica
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Richardson, Matt
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Schagatay, Erika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Spleen contraction and erythrocyte release in elite apnea divers during submaximal and maximal effort apneas2009In: 14th Annual Congress of the ECSS in Oslo, Norway 24-27 June 2009, 2009Conference paper (Refereed)
  • 11.
    Richardson, Matt
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    de Bruijn, Robert
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Schagatay, Erika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Hypoxia augments apnea-induced increase in hematocrit and hemoglobin concentration2009In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 105, no 1, p. 63-68Article in journal (Refereed)
    Abstract [en]

    Increased hemoglobin concentration (Hb) and hematocrit (Hct) attributable to spleen contraction raises blood gas storage capacity during apnea, but the mechanisms that trigger this response have not been clarified. We focused on the role of hypoxia in triggering these Hb and Hct elevations. After horizontal rest for 20 min, 10 volunteers performed 3 maximal apneas spaced by 2 min, each preceded by a deep inspiration of air. The series was repeated using the same apneic durations but after 1 min of 100% oxygen breathing and oxygen inspiration prior to apneas. Mean apneic durations were 150s, 171s, and 214s for apneas 1, 2, and 3, respectively. Relative to pre-apnea values, the mean post-apneic arterial oxygen saturation nadir was 84.7% after air and 98% after oxygen. A more pronounced elevation of both Hb and Hct occurred during the air trial: after apnea 1 with air, mean Hb had increased by 1.5% (P<0.01), but no clear increase was found after the first apnea in with oxygen. After the third apnea with air Hb had increased by 3.0% (P<0.01), and with oxygen by 2.0% (P<0.01). After the first apnea with air Hct had increased by 1.9% (P<0.01) and after 3 apneas by 3.0% (P<0.01), but Hct did not change significantly in the oxygen trial. In both trials, Hb and Hct were at pre-apneic levels 10 min after apneas. Diving bradycardia during apnea was the same in both trials. We concluded that hypoxia is essential in inducing spleen-related Hb and Hct increase during apnea.

  • 12.
    Richardson, Matt
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Engan, Harald
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Lodin-Sundström, Angelica
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Schagatay, Erika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Effect of hypercapnia on spleen-related haemoglobin increase during apnea2012In: Diving and Hyperbaric Medicine, ISSN 1833-3516, Vol. 42, no 1, p. 4-9Article in journal (Refereed)
    Abstract [en]

    BACKGROUND:

    Splenic contraction associated with apnea causes increased haemoglobin concentration and haematocrit (Hct), an effect that may promote prolonged breath-holding. Hypoxia has been shown to augment this effect, but hypercapnic influences have not been investigated previously.

    METHODS:

    Eight non-divers performed three series of apneas on separate days after inspiration of oxygen with different carbon dioxide (CO₂) levels. Each series consisted of three apneas 2 minutes apart: one with pre-breathing of 5% CO₂ in oxygen (O₂, 'Hypercapnia'); one with pre-breathing of 100% O₂ ('Normocapnia'); and one with hyperventilation of 100% O₂ ('Hypocapnia'). The apnea durations were repeated identically in all trials, determined from the maximum duration attained in the CO₂ trial. A fourth trial, breathing 5% CO₂ in O₂ for the same duration as these apneas was also performed ('Eupneic hypercapnia'). In three subjects, spleen size was measured using ultrasonic imaging.

    RESULTS:

    Haemoglobin increased by 4% after apneas in the 'Hypercapnia' trial (P = 0.002) and by 3% in the 'Normocapnia' trial (P = 0.011), while the 'Hypocapnia' and 'Eupneic hypercapnia' trials showed no changes. The 'easy' phase of apnea, i.e., the period without involuntary breathing movements, was longest in the 'Hypocapnia' trial and shortest in the 'Hypercapnia' trial. A decrease in spleen size was evident in the hypercapnic trial, whereas in the hypocapnia trial spleen size increased, while only minor changes occurred in the other trials. No differences were observed between trials in the cardiovascular diving response.

    CONCLUSION:

    There appears to be a dose-response effect of CO₂ on triggering splenic contraction during apnea in the absence of hypoxia.

  • 13.
    Richardson, Matt
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Lodin, Angelica
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Engan, Harald
    Schagatay, Erika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Hypercapnia moderates hemoglobin increases during apneaManuscript (Other academic)
  • 14.
    Richardson, Matt
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Lodin, Angelica
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Reimers, J
    Schagatay, Erika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Short-term effects of normobaric hypoxia on the human spleen2008In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 104, no 2, p. 395-399Article in journal (Refereed)
    Abstract [en]

    Spleen contraction resulting in an increase in circulating erythrocytes has been shown to occur during apnea. This effect, however, has not previously been studied during normobaric hypoxia whilst breathing. After 20 min of horizontal rest and normoxic breathing, five subjects underwent 20-min of normobaric hypoxic breathing (12.8% oxygen) followed by 10 min of normoxic breathing. Ultrasound measurements of spleen volume and samples for venous hemoglobin concentration (Hb) and hematocrit (Hct) were taken simultaneously at short intervals from 20 min before until 10 min after the hypoxic period. Heart rate, arterial oxygen saturation (SaO2) and respiration rate were recorded continuously. During hypoxia, a reduction in SaO2 by 34% (P < 0.01) was accompanied by an 18% reduction in spleen volume and a 2.1% increase in both Hb and Hct (P < 0.05). Heart rate increased 28% above baseline (P < 0.05). Within 3 min after hypoxia SaO2 had returned to pre-hypoxic levels, and spleen volume, Hb and Hct had all returned to pre-hypoxic levels within 10 min. Respiratory rate remained stable throughout the protocol. This study of short-term exposure to eupneic normobaric hypoxia suggests that hypoxia plays a key role in triggering spleen contraction and subsequent release of stored erythrocytes in humans. This response could be beneficial during early altitude acclimatization.

  • 15.
    Richardson, Matt
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Lodin-Sundström, Angelica
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Schagatay, Erika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Spleen contraction in accessory spleens during apnea in elite divers2009In: Abstract EUBS Aberdeen, UK, 25-28 Aug, 2009, 2009Conference paper (Refereed)
  • 16.
    Richardson, Matt X.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Hematological changes arising from spleen contraction during apnea and altitude in humans2008Doctoral thesis, comprehensive summary (Other academic)
  • 17.
    Richardson, Matthew
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Cheung, S
    Connolly, J
    Streimer, C
    White, M
    Event-related potential amplitude and latency changes of the P300 wave in response to whole-body cooling.Manuscript (Other academic)
    Abstract [en]

    Cold exposure can result in core body temperature reductions and subsequent physiological and psychological effects. While the physiological effects of core temperature cooling have been well documented, a precise method of quantification of cognitive performance during cold stress is yet to be established. We investigated the effects of a 1oC drop in rectal temperature in male subjects at two different exposure temperatures (5oC and 12oC circulated water in a liquid-cooled garment) on the P300 event-related potential waveform during a dual modality (auditory and visual) continuous performance task. Changes in waveform amplitude and latency suggested modification of task engagement or perceived difficulty, and speed of processing, respectively. Decreases in amplitude occurred in both 5oC and 12oC conditions, and increases in latency occurred in the 5oC condition compared to control subjects. It was suggested that cognitive performance suffered in terms of task engagement as rectal temperature decreased, with speed of processing slowed in the 5oC condition. The further use of event-related potential recordings in future thermal studies is discussed.

  • 18.
    Richardson, Matthew
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    de Bruijn, Robert
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Holmberg, Hans-Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Björklund, Glenn
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Haughey, Helena
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Schagatay, Erika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Increase of hemoglobin concentration after maximal apneas in divers, skiers and untrained humans2005In: Canadian Journal of Applied Physiology, ISSN 1066-7814, Vol. 30, no 3, p. 276-281Article in journal (Refereed)
    Abstract [en]

    Apnea is physiologically stressful and can within a short time frame pose a threat to survival. To sustain prolonged apnea, oxygen use should be minimized and its storage maximized. Two mechanisms known to have this effect are the cardiovascular diving response, directing the available oxygen selectively to the heart and brain, and spleen contraction increasing the circulating erythrocyte volume and thereby gas storage capacity. Spleen contraction is also observed after maximal exercise, and is thought to enhance aerobic performance. While the cardiovascular diving response is known to be more pronounced after apnea training, spleen contraction has not been studied in conjunction with apnea training or other types of training. The aim of the present investigation is to study the hematological responses to apnea performed during rest by elite apneic divers, by elite cross-country skiers and by untrained subjects. After 20 min of rest, subjects performed 3 maximal apneas spaced by 2 min normal breathing intervals. Blood samples were drawn before, directly after, and 10 min after the apnea series and hemoglobin concentration was measured. All groups responded to maximal apneas with an increase in hemoglobin concentration, which had disappeared after 10 min of recovery. The increase in hemoglobin concentration was more pronounced in the apneic divers (4g/L) than in skiers (3g/L) and untrained subjects (2g/L; P < 0.05). All groups prolonged their apneic times through the series, but the increase was most evident for the divers versus both the skiers (P < 0.05) and untrained subjects (P < 0.01). The results suggest that these responses could be more pronounced as a result of apnea training.

  • 19.
    Richardson, Matthew
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    de Bruijn, Robert
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Pettersson, Sofia
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Reimers, J.
    Schagatay, Erika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    CORRELATION BETWEEN SPLEEN SIZE AND HEMATOCRIT DURING APNEA IN HUMANS2006In: Proceedings of the Undersea and Hyperbaric Medical Society/Divers Alert Network 2006 June 20-21 Workshop. Durham, NC, 2006Conference paper (Other academic)
  • 20.
    Richardson, Matthew
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    de Bruijn, Robert
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Schagatay, Erika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Hypoxia - A trigger for spleen contraction?2005In: EUBS 2005, 2005Conference paper (Other scientific)
    Abstract [en]

    Several mechanisms involving oxygen conservation or increased blood gas storage capacity serve to facilitate prolonged diving in mammals. Two such mechanisms present in humans are the cardiovascular �diving response� and the blood boosting spleen contraction. Repeated diving may elicit these adaptive responses by similar or different mechanisms. Increased hematocrit (Hct) attributable to spleen contraction raises blood gas storage capacity during human apneic diving or simulated diving, but the underlying mechanisms have not been clarified. The time course for development of the Hct response is slower than for the cardiovascular diving response: The development of spleen contraction is progressive across 3 serial apneas, and recovery takes 8-9 minutes. Also, while the diving response is initiated by apnea and fortified by facial chilling, the stimulus eliciting Hct increase is related to apnea alone. Thus apnea itself or its consequences appear to be the main stimulus. In this study we focused on the role of hypoxia in triggering spleen induced elevations in Hct. After horizontal rest for 20 min, nine volunteers performed 3 maximal apneas spaced by 2 min of rest, preceeded by an inspiration of normal air. The series was repeated at a different day using the same apneic durations but after 60 s of 100% oxygen breathing and oxygen inspiration prior to apneas. Relative to pre-apnea values, the post apneic arterial oxygen saturation nadir averaged 84% after the air trial and 99% after the oxygen trial. The Hct rose in both protocols, but with about twice the magnitude after apneas with air. A relative increase of 2.7% was found after three apneas with air (p<0.01), and 1.4% increase after three apneas with oxygen (p<0.05). Values returned to pre-apneic levels within 10 minutes. We conclude that hypoxia may be an important modifying factor influencing the magnitude of hematocrit increase during apnea.

  • 21.
    Richardson, Matthew
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Schagatay, Erika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Altitude attenuates apnea-induced increase in haemoglobin concentration2007In: International Conference on Environmental Ergonomics, 2007Conference paper (Other academic)
    Abstract [en]

    INTRODUCTION During apnea at sea-level, a contraction of the spleen is found in humans (Hurford et al 1990) causing a transient increase in hemoglobin concentration (Hb) and hematocrit (Schagatay et al 2001). The development of these increases is progressive across 3 serial apneas, typically resulting in Hb increases of 2% (Richardson et al, 2003), and recovery to pre-apneic values within 8-9 minutes (Schagatay et al 2005). The spleen contraction-associated Hb increase is in part triggered by the hypoxia occurring during apnea (Richardson et al 2005). The Hb increase leads to increased blood gas storage capacity which facilitates prolonged apnea in humans and may be responsible for the known prolongation of serial apneas (Schagatay et al 2001). At altitude, we suggest that the chronic hypoxia could induce splenic contraction during eupnea in humans, as previously observed in mice (Cook and Alafi 1956). Our aim was to reveal whether spleen related Hb increase occurs during eupneic altitude exposure in humans, thereby abolishing the Hb increase normally seen during apnea.

  • 22.
    Richardson, Matthew
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Schagatay, Erika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    de Bruijn, Robert
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Haughey, Helena
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Hematological response pattern associated with maximal-duration apnea series in untrained subjects: Annual Meeting of the European Underwater and Baromedical Society, Copenhagen, Denmark.2003Conference paper (Other academic)
    Abstract [en]

    Background: In addition to the human cardiovascular ‘diving response’, i.e., bradycardia and peripheral vasoconstriction during apnea, recent studies have shown that spleen contraction also occurs during repeated apneas. This latter response may serve to expel erythrocytes into the circulation to promote gas transportation. However, prospective changes in blood parameters after repeated apneas have yet to be systematically described. As is the case with diving response parameters, some individuals may have stronger haematological changes from performing apneic series than others. These variations need to be considered in future studies of the function of the spleen and blood components during apnea. The present study was aimed to describe the haematological response pattern associated with repeated maximal apneas in healthy non-divers. Methods: After 20 min of rest, 46 healthy untrained subjects of both sexes performed three maximal apneas, spaced by two minutes rest and normal breathing. Blood samples were taken before, within 1 minute after, and 10 minutes after the apneic series and analyzed for changes in haemoglobin (Hb) concentration and hematocrit (Hct). Results: Pre-apnea Hb concentration (mean±SE) was normally distributed (147.1±1.6 g/L). An increase of 2.1±0.3% in the Hb value was seen immediately post-series, followed by a decrease from this value of 1.8±0.3% at 10 minutes post-series. Pre-apnea hematocrit (41.2±0.6 percent) showed a similar increase immediately post-series of 3.2±0.8% followed by a decrease of 1.6±0.4% from this value at 10 minutes post-series. Classifying subjects as strong responders (above 75th percentile) and weak responders (below 25th percentile) resulted in mean increases in Hb and Hct above pre-apneic values of 4.7±0.4% and 7.1±2.1%, respectively for strong responders, and -0.5±0.4 and 0.5±0.6, respectively for weak responders. Conclusion: Significant increases in Hb and Hct values occur immediately after a maximal apneic series, followed by a return towards baseline values after 10 minutes. These increases may be due to the spleen contraction as demonstrated in previous research. Furthermore, some subjects appear to respond more strongly than others, and pre-screening for these types of responders may be judicious in future testing. The mechanism(s) underlying the strength of these haematological responses warrants further investigation.

  • 23.
    Schagatay, Erika
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    de Bruijn, Robert
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Richardson, Matthew
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Increase in hematocrit after short and long term apnea training2005In: Blue 2005. Human Behaviour and Limits in Underwater Environments. Abstract book: International Conference organised by: CNR Institute of Clinical Physiology, Pisa - Italy Apnea Academy - Italy University of Chieti - Italy. Pisa December 1-4 2005., Pisa: CNR Institute of Clinical Physiology , 2005, p. 57-58Conference paper (Refereed)
  • 24.
    Schagatay, Erika
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    de Bruijn, Robert
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Richardson, Matthew
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Increases in diving response, hematocrit and asphyxia tolerance after apnea training2005Conference paper (Other scientific)
  • 25.
    Schagatay, Erika
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Engan, H
    Lodin-Sundström, Angelica
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Richardson, Matt
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Increase in reticulocyte count after 2 weeks of apne training: Meeting abstract2009In: Journal of Physiological Sciences, Suppl 1, 2009, Tokyo: Springer, 2009, p. 496-496Conference paper (Refereed)
  • 26.
    Schagatay, Erika
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Lodin, Angelica
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Richardson, Matt
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Lung volume and diving performance in elite apneists2007In: Proceedings. 33rd EUBS Annual Scientific Meeting, Sharm el Sheik, Egypt, 8-15 September 2007, 2007Conference paper (Refereed)
    Abstract [en]

    Background The ability to perform extended apnea depends mainly on 3 factors: a) the total body gas storage capacity (in blood, tissues and lungs), b) the tolerable levels of hypoxia and hypercapnia, and c) the ability to restrict metabolism (work economy and diving response). To maximize lung volume is an obvious way to increase a), and large lungs with small residual volume are also beneficial for reaching great depths without risking squeeze. Negative effects of large lung volume may be increased surface buoyancy and high intra-thoracic pressure, with a negative effect on venous return, risk of syncope, and a decreased diving response, which is important for c). However, trained divers have previously been reported to have large lungs (Carey et al 1956) and the positive effects may outweigh the disadvantages. The present study evaluated if large lungs are associated with good results in competitive apneic diving. Methods Height, weight and vital capacity (VC), without lung packing, were recorded in 14 male apneic divers participating in the apnea world championship in Hurgada 2006. Their previous apnea training experience was 5.8(1.2) years. Individual total competition scores i.e. the accumulated points from dives of maximal depth, time and distance, were compared with lung volumes. Results Subject mean(SE) height was 184(2) cm, weight was 82(3) kg and VC was 7.3(0.3) L. Mean dive performance of these subjects was 75(4) m for constant weight deep diving, 5 min 53(39) s for static apnea (resting submersion) and 139(13) m for dynamic apnea (pool distance). A Pearson´s correlation test revealed that lung volume was positively correlated with the total competition score (r = 0.54; P<0.05). Individual height and weight were not correlated with performance. Conclusions We conclude that large lung volume may contribute to successful apnea performance in humans and that any negative effects are outweighed by benefits.

  • 27.
    Schagatay, Erika
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Richardson, Matt
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    de Bruijn, Robert
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Haughey, Helena
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Holmberg, Hans Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Naturlig bloddopning vid fysiologisk stress2004In: Svensk idrottsforskning, ISSN 1103-4629, Vol. 13, no 1, p. 18-21Article in journal (Other academic)
  • 28.
    Schagatay, Erika
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Richardson, Matt
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Lodin, Angelica
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Spleen and lung volumes correlate with performance in elite apnea diversManuscript (Other academic)
  • 29.
    Schagatay, Erika
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Richardson, Matt
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Lodin-Sundström, Angelica
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Engan, H
    Hypercapnia augments spleen contraction and Hb increase during apnea: Meeting abstract2009In: Journal of Physiological Sciences Suppl 1, 2009, Tokyo: Springer, 2009, p. 268-268Conference paper (Refereed)
  • 30.
    Schagatay, Erika
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Richardson, Matt X.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Lodin-Sundström, Angelica
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Size matters: Spleen and lung volumes predict performance in human apneic divers2012In: Frontiers in Physiology, ISSN 1664-042X, Vol. 3, no JUN, p. Art. no. 173-Article in journal (Refereed)
    Abstract [en]

    Humans share with seals the ability to contract the spleen and increase circulating hemat-ocrit, which may improve apneic performance by enhancing gas storage. Seals have large spleens and while human spleen size is small in comparison, it shows great individual variation. Unlike many marine mammals, human divers rely to a great extent on lung oxygen stores, but the impact of lung volume on competitive apnea performance has never been determined. We studied if spleen- and lung size correlated with performance in elite apnea divers. Volunteers were 14 male apnea world championship participants, with a mean (SE) of 5.8 (1.2)years of previous apnea training. Spleen volume was calculated from spleen length, width, and thickness measured via ultrasound during rest, and vital capacity via spirometry. Accumulated competition scores from dives of maximal depth, time, and distance were compared to anthropometric measurements and training data. Mean (SE) diving performance was 75 (4) m for constant weight depth, 5 min 53 (39) s for static apnea and 139 (13) m for dynamic apnea distance. Subjects' mean height was 184 (2) cm, weight 82 (3) kg, vital capacity (VC) 7.3 (0.3) L and spleen volume 336 (32) mL. Spleen volume did not correlate with subject height or weight, but was positively correlated with competition score (r = 0.57; P< 0.05). Total competition score was also positively correlated with VC (r = 0.54; P<0.05). The three highest scoring divers had the greatest spleen volumes, averaging 538 (53) mL, while the three lowest-scoring divers had a volume of 270 (71) mL (P < 0.01). VC was also greater in the high-scorers, at 7.9 (0.36) L as compared to 6.7 (0.19) L in the low scorers (P<0.01). Spleen volume was reduced to half after 2 min of apnea in the highest scoring divers, and the estimated resting apnea time gain from the difference between high and low scorers was 15s for spleen volume and 60s forVC. We conclude that both spleen- and lung volume predict apnea performance in elite divers. © 2012 Schagatay, Richardson and Lodin-Sundström.

  • 31.
    Schagatay, Erika
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Richardson, Matthew
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    de Bruijn, Robert
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Andersson, J.
    Cardiovascular and hematological adjustments to apneic diving in humans. -Is the 'spleen-response' part of the diving response?2006In: Breath-hold diving 2006: UHMS proceedings, Orlando, USA, June 20-24, 2006, p. 20-24Conference paper (Refereed)
1 - 31 of 31
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