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Schagatay, Erika
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Publications (10 of 133) Show all publications
Fernández, F. d., Rodríguez-Zamora, L. & Schagatay, E. (2019). Hook Breathing Facilitates SaO2 Recovery After Deep Dives in Freedivers With Slow Recovery. Frontiers in Physiology, 10, 1-8, Article ID 1076.
Open this publication in new window or tab >>Hook Breathing Facilitates SaO2 Recovery After Deep Dives in Freedivers With Slow Recovery
2019 (English)In: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 10, p. 1-8, article id 1076Article in journal (Refereed) Published
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.

Keywords
apnea, breath-hold, respiration, hypoxia, syncope, blackout, pulmonary edema, freediving safety
National Category
Health Sciences
Identifiers
urn:nbn:se:miun:diva-37212 (URN)10.3389/fphys.2019.01076 (DOI)000483335500001 ()2-s2.0-85072732502 (Scopus ID)
Note

This article was submitted to Exercise Physiology, a section of the journal Frontiers in Physiology.

Available from: 2019-09-13 Created: 2019-09-13 Last updated: 2019-11-14Bibliographically approved
Schagatay, E. & Åman, P. A. (2019). Repeated freediving – An efficient and safe method to rescue subjects trapped in cars underwater. Safety Science, 118, 752-756
Open this publication in new window or tab >>Repeated freediving – An efficient and safe method to rescue subjects trapped in cars underwater
2019 (English)In: Safety Science, ISSN 0925-7535, E-ISSN 1879-1042, Vol. 118, p. 752-756Article in journal (Refereed) Published
Abstract [en]

A method based on repeated freediving was developed to rescue subjects trapped in cars underwater – a scenario leading to 5–6 annual deaths in Sweden, and thousands globally. We determined rescue time and whether the divers were at risk of hypoxic blackout. Cars containing 5 kg negatively buoyant rescue-dummies strapped with seatbelts were placed on 5 m and 8 m depth. Eight freediving-instructors made 230 freedives, working in pairs with one diver always at the surface. For each rescue, two freedivers, equipped with mask, snorkel, fins, weight-belt, wetsuit and a buoy with belt-cutter and glass-breaker freedived alternating in turns between the divers. They accomplished a maximum of one of the following tasks per dive; (1) Finding the car; (2) Marking car with buoy; (3) Opening door/crushing window. (4) Opening/cutting belt; (5) Retrieving dummy to surface; (6) Transporting dummy to shore. Dummies were retrieved to shore from 5 m depth within a mean (SD) duration of 4 min 16 s (1 min 36 s) and from 8 m within 6 min 22 s (2 min 13 s; P &lt; 0.05). Mean dive duration was 28(7)s (14–46 s), with 3 dives over 40 s duration. Freedivers arterial oxygen saturation (SaO2) levels were measured in dives of 30, 35, 40 and 45 s using pulse oximetry. Mean (SD) SaO2 at 20 s after surfacing was 90% for 45 s dives. This allows rapid recovery and gives a safety margin to the 50% SaO2 level when divers may risk blackout. We concluded that repeated freediving is efficient for rescuing victims trapped in cars underwater within their survival time, and following recommended methods and dive durations, rescue divers are not exposed to risk. 

Keywords
Apnea, Breath-hold divining, Education, Hypoxia, Rapid rescue, Survival, Training, Oximeters, Personnel training, Breath holds, Noninvasive medical procedures
National Category
Health Sciences
Identifiers
urn:nbn:se:miun:diva-36679 (URN)10.1016/j.ssci.2019.05.023 (DOI)000475999000069 ()2-s2.0-85067196181 (Scopus ID)
Available from: 2019-07-09 Created: 2019-07-09 Last updated: 2019-08-12Bibliographically approved
Holmström, P., Mulder, E., Lodin-Sundström, A., Limbu, P. & Schagatay, E. (2019). The Magnitude of Diving Bradycardia During Apnea at Low-Altitude Reveals Tolerance to High Altitude Hypoxia. Frontiers in Physiology, 10, 1-12, Article ID 1075.
Open this publication in new window or tab >>The Magnitude of Diving Bradycardia During Apnea at Low-Altitude Reveals Tolerance to High Altitude Hypoxia
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2019 (English)In: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 10, p. 1-12, article id 1075Article in journal (Refereed) Published
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.

Keywords
acute mountain sickness, breath-hold diving, hypoxia, prediction, cardiovascular diving response, spleen
National Category
Health Sciences
Identifiers
urn:nbn:se:miun:diva-37117 (URN)10.3389/fphys.2019.01075 (DOI)000482202400001 ()2-s2.0-85072189253 (Scopus ID)
Available from: 2019-09-05 Created: 2019-09-05 Last updated: 2019-09-24Bibliographically approved
Rodríguez-Zamora, L., Engan, H. K., Lodin-Sundström, A., Schagatay, F., Iglesias, X., Rodriguez, F. A. & Schagatay, E. (2018). Blood lactate accumulation during competitive freediving and synchronized swimming. Undersea & Hyperbaric Medicine, 45(1), 55-63
Open this publication in new window or tab >>Blood lactate accumulation during competitive freediving and synchronized swimming
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2018 (English)In: Undersea & Hyperbaric Medicine, ISSN 1066-2936, Vol. 45, no 1, p. 55-63Article in journal (Refereed) Published
Abstract [en]

A number of competitive water sports are performed while breath-holding (apnea). Such performances put large demands on the anaerobic system, but the study of lactate accumulation in apneic sports is limited. We therefore aimed to determine and compare the net lactate accumulation (NLA) during competition events in six disciplines of competitive freediving (FD) and three disciplines of synchronized swimming (SSW). The FD disciplines were: static apnea (STA; n = 14) dynamic apnea (DYN; n = 19) dynamic apnea no fins (DNF; n = 16) constant weight (CWT; n = 12) constant weight no fins (CNF; n = 8) free immersion (FIM; n =10) The SSW disciplines were solo (n = 21), duet (n = 31) and team (n = 34). Capillary blood lactate concentration was measured before and three minutes after competition performances, and apneic duration and performance variables were recorded. In all nine disciplines NLA was observed. The highest mean (SD) NLA (mmol.L-1) was found in CNF at 6.3 (2.2), followed by CWT at 5.9 (2.3) and SSW solo at 5 (1.9). STA showed the lowest NLA 0.7 (0.7) mmol.L-1 compared to all other disciplines (P < 0.001). The NLA recorded shows that sports involving apnea involve high levels of anaerobic activity. The highest NLA was related to both work done by large muscle groups and long apneic periods, suggesting that NLA is influenced by both the type of work and apnea duration, with lower NLA in SSW due to shorter apneic episodes with intermittent breathing.

Keywords
apnea, anaerobic, breath-hold diving, exercise, hypoxia, underwater, sports
National Category
Health Sciences
Identifiers
urn:nbn:se:miun:diva-33680 (URN)000431654400008 ()29571233 (PubMedID)2-s2.0-85060948755 (Scopus ID)
Available from: 2018-05-31 Created: 2018-05-31 Last updated: 2019-03-19Bibliographically approved
Patrician, A., Engan, H. K., Lundsten, D., Grote, L., Vigetun-Haughey, H. & Schagatay, E. (2018). The Effect of Dietary Nitrate on Nocturnal Sleep-Disordered Breathing and Arterial Oxygen Desaturation at High Altitude. High Altitude Medicine & Biology, 19(1), 21-27
Open this publication in new window or tab >>The Effect of Dietary Nitrate on Nocturnal Sleep-Disordered Breathing and Arterial Oxygen Desaturation at High Altitude
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2018 (English)In: High Altitude Medicine & Biology, ISSN 1527-0297, E-ISSN 1557-8682, Vol. 19, no 1, p. 21-27Article in journal (Refereed) Published
Abstract [en]

Patrician, Alexander, Harald Engan, David Lundsten, Ludger Grote, Helena Vigetun-Haughey, and Erika Schagatay. The effect of dietary nitrate on nocturnal sleep-disordered breathing and arterial oxygen desaturation at high altitude. High Alt Med Biol 00:000-000, 2017.Sleep-disordered breathing and fluctuations in arterial oxygen saturation (SaO(2)) are common during sleep among lowlanders ascending to high altitude. Dietary nitrate (NO3-) supplementation has been shown to lower the O-2 consumption in various conditions. Our objective was to investigate whether dietary NO3- could reduce sleep-disordered breathing and SaO(2) desaturation during sleep at altitude. Cardiorespiratory responses during sleep were measured in 10 healthy lowlanders at 330m and then again in the Himalayas at 3700-4900m. Each subject received two 70mL shots of either beetroot juice (BR; approximate to 5.0mmol NO3- per shot) or placebo (PL: approximate to 0.003mmol NO3- per shot) in a single-blinded, weighted order over two consecutive nights at altitude. At 2.5-4.5 hours into sleep at altitude, BR increased the SaO(2) desaturation drop (4.2 [0.1]% with PL vs. 5.3 [0.4]% with BR; p=0.024) and decreased the SaO(2) desaturation duration (14.1 [0.9] seconds with PL to 11.1 [0.9] seconds with BR; p=0.0.041). There was a reduction in breaths with flow limitation (p=0.025), but no changes in Apnea-Hypopnea Index (AHI), mean and minimum SaO(2). The study suggests BR supplementation does not improve AHI or oxygenation, but may increase fluctuations in arterial O-2 saturation during sleep at altitude in native lowlanders.

Keywords
arterial oxygen desaturation, dietary nitrate, hypobaric hypoxia, pulmonary vasculature, sleep at high altitude
National Category
Sport and Fitness Sciences
Identifiers
urn:nbn:se:miun:diva-32569 (URN)10.1089/ham.2017.0039 (DOI)000417305600001 ()2-s2.0-85044988132 (Scopus ID)
Available from: 2017-12-21 Created: 2017-12-21 Last updated: 2019-08-06Bibliographically approved
Patrician, A. & Schagatay, E. (2017). Dietary nitrate enhances arterial oxygen saturation after dynamic apnea. Scandinavian Journal of Medicine and Science in Sports, 27(6), 622-626
Open this publication in new window or tab >>Dietary nitrate enhances arterial oxygen saturation after dynamic apnea
2017 (English)In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 27, no 6, p. 622-626Article in journal (Refereed) Published
Abstract [en]

Breath-hold divers train to minimize their oxygen consumption to improve their apneic performance. Dietary nitrate has been shown to reduce the oxygen cost in a variety of situations, and our aim was to study its effect on arterial oxygen saturation (SaO2) after dynamic apnea (DYN) performance. Fourteen healthy male apnea divers (aged 33 ± 11 years) received either 70 mL of concentrated nitrate-rich beetroot juice (BR) or placebo (PL) on different days. At 2.5 h after ingesting the juice, they were asked to perform 2 × 75 m DYN dives in a pool with 4.5-min recovery between dives. Each dive started after 2-min countdown and without any warm-up apneas, hyperventilation, or lung packing. SaO2 and heart rate were measured via pulse oximetry for 90 s before and after each dive. Mean SaO2 nadir values after the dives were 83.4 ± 10.8% with BR and 78.3 ± 11.0% with PL (P &lt; 0.05). At 20-s post-dive, mean SaO2 was 86.3 ± 10.6% with BR and 79.4 ± 10.2% with PL (P &lt; 0.05). In conclusion, BR juice was found to elevate SaO2 after 75-m DYN. These results suggest an oxygen conserving effect of dietary nitrate supplementation, which likely has a positive effect on maximal apnea performance.

Keywords
Anaerobic exercise, Apneic diving, Arterial desaturation, Breath-hold, Hypoxia, Immersion, Nitrate, Sport performance
National Category
Sport and Fitness Sciences
Identifiers
urn:nbn:se:miun:diva-29605 (URN)10.1111/sms.12684 (DOI)000400610600005 ()27037996 (PubMedID)2-s2.0-84963617381 (Scopus ID)
Note

First published: 31 March 2016

Available from: 2016-12-15 Created: 2016-12-15 Last updated: 2017-07-04Bibliographically approved
Schagatay, E., Johansson, O. & Abrahamsson, E. (2017). Diving Response and Lung Capacity of Philippine Sama-Bajau Professional Breath-Hold Divers. Paper presented at Scandinavian Physiological Society Meeting in Oslo, Norway, 26-28 August 2016. Acta Physiologica, 219(S710), Article ID P-66.
Open this publication in new window or tab >>Diving Response and Lung Capacity of Philippine Sama-Bajau Professional Breath-Hold Divers
2017 (English)In: Acta Physiologica, ISSN 1748-1708, E-ISSN 1748-1716, Vol. 219, no S710, article id P-66Article in journal, Meeting abstract (Refereed) Published
Abstract [en]

INTRODUCTION: Freedivers possess several special physiological features and have been reported to have stronger diving response and larger vital capacity (VC) than non-divers. Several populations in South-East Asia live as marine hunter-gatherers dependent upon daily freediving with little equipment. One group is the Sama-Bajau in Indonesia, Philippines and Malaysia. Our aim was to investigate the diving response and lung physiology of the Sama-Bajau breath-hold diving population in the Phillipines, which has not previously been studied. 

MATERIALS AND METHODS: Nine male professional breath-hold divers were recruited from a Sama-Bajau diving community near Davao in the Philippines. Their mean(SD) age was 27(3)years, height 166(2)cm, and weight 58(2)kg. Divers made simulated dives by maximal apneas with face immersion in cool water, while heart-rate (HR) was recorded to determine the diving response by the HR reduction. Lung variables were measured using a portable spirometer, and diving time and depth of working dives in the sea were logged.

RESULTS: Mean(SE) HR-reduction was 39(3)%, at a maximal voluntary apnea of 67(7)s duration. VC was 3.9(0.6)L (96% of predicted for a Malaysian population, NS) and forced expiratory volume in the 1st second/forced VC was 89.6(3.4)% (105% of predicted, P<0.05). Maximal diving depth was 15 m, and mean depth 5(2) m. Diving shifts lasted 2-3h, with approximately 50% of the time spent underwater.

CONCLUSION: The diving response was more pronounced than in non divers but in the range typical for breath-hold divers. VC was similar to predicted for non-divers but smaller than in e.g. competition divers. FEV1/FVC was slightly higher than in the normal population. We concluded that long term daily "natural" diving to 5-15m does not increase lung volume, but may have some effects on lung function.

National Category
Health Sciences
Identifiers
urn:nbn:se:miun:diva-29759 (URN)000393916600091 ()
Conference
Scandinavian Physiological Society Meeting in Oslo, Norway, 26-28 August 2016
Available from: 2016-12-22 Created: 2016-12-22 Last updated: 2017-11-29Bibliographically approved
Schagatay, E., Patrician, A., Engan, H. & Lodin-Sundström, A. (2017). Spleen Contraction and Hb Increase after Nitrate Ingestion may Explain Enhanced Apneic Diving Performance. Paper presented at Scandinavian Physiological Society Meeting in Oslo, Norway, 26-28 August 2016. Acta Physiologica, 219(S710), 32-32, Article ID P-42.
Open this publication in new window or tab >>Spleen Contraction and Hb Increase after Nitrate Ingestion may Explain Enhanced Apneic Diving Performance
2017 (English)In: Acta Physiologica, ISSN 1748-1708, E-ISSN 1748-1716, Vol. 219, no S710, p. 32-32, article id P-42Article in journal, Meeting abstract (Refereed) Published
Abstract [en]

INTRODUCTION: Ingesting nitrate-rich beetroot juice (BJ) has been suggested to enhance physical performance by reducing the oxygen cost, which could be useful in apneic diving. We previously found that after ingestion of BJ, arterial oxygen saturation was higher after static apneas (Engan et.al, Resp. Physiol & Neurobiol, 2012) and after dynamic apneas involving exercise (Patrician & Schagatay. Scand.J.Med.Sci.Sports, 2016). Our aim was to investigate the effect of BJ ingestion on spleen contraction and the resulting Hb increase, a mechanism known to prolong apneas (Schagatay et.al, J.Appl.Physiol, 2001).

MATERIALS AND METHODS: Eight volunteers aged 24±2 years simulated diving by performing maximal apneas with face immersion during prone rest ~2.5h after ingesting 70 ml BJ (5 mmol NO3-) or placebo (0.003 mmol NO3-) on separate days in a weighted order. We measured spleen diameters for volume calculation and capillary Hb before and after "dives".

RESULTS: Baseline (mean±SE) spleen volume was 269±33 mL with placebo and 206±27 mL after BJ ingestion (P<0.05). Post "dive" spleen volumes were smaller, but similar at 168±35 mL and 193±25 mL, respectively (NS). Baseline Hb was 145.4±3.4 g/L with placebo and 149.8±2.6 g/L with BJ (P<0.05). Post "dive" Hb had increased to 152.0±4.8 g/L with placebo and 153.7±3.0 g/L with BJ (NS). 

CONCLUSION: With BJ ingestion spleen volume was reduced and Hb elevated even before the "dive". The elevated Hb at the start of apnea would likely have a positive effect on apneic duration by enhancing circulating oxygen stores. The positive effect of nitrate on performance in various sports could in part be due to its spleen-emptying effect, causing a natural blood boosting, which is a novel finding.

National Category
Health Sciences
Identifiers
urn:nbn:se:miun:diva-29758 (URN)000393916600067 ()
Conference
Scandinavian Physiological Society Meeting in Oslo, Norway, 26-28 August 2016
Available from: 2016-12-22 Created: 2016-12-22 Last updated: 2017-12-14Bibliographically approved
Schagatay, E. (2016). Diving methods of the Japanese Ama and the Sama-Bajau waterpeople in South East Asia. In: : . Paper presented at HADS workshop, UHMS Conference, Las Vegas, June 8-11, 2016.
Open this publication in new window or tab >>Diving methods of the Japanese Ama and the Sama-Bajau waterpeople in South East Asia
2016 (English)Conference paper, Oral presentation with published abstract (Other academic)
National Category
Health Sciences
Identifiers
urn:nbn:se:miun:diva-29757 (URN)
Conference
HADS workshop, UHMS Conference, Las Vegas, June 8-11, 2016
Available from: 2016-12-22 Created: 2016-12-22 Last updated: 2016-12-22Bibliographically approved
Rodríguez-Zamora, L., Patrician, A., Starfelt, V., Olander, C., Lodin-Sundström, A. & Schagatay, E. (2016). Physiological responses to apnea at sea level predict SaO2 at simulated 5300 m altitude. In: : . Paper presented at 8th European Hypoxia Symposium: High altitude and isobaric hypoxia influence on human performance: science and practice, Police, Slovenia, 8 - 11 September 2016.
Open this publication in new window or tab >>Physiological responses to apnea at sea level predict SaO2 at simulated 5300 m altitude
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2016 (English)Conference paper, Oral presentation with published abstract (Refereed)
National Category
Health Sciences
Identifiers
urn:nbn:se:miun:diva-29760 (URN)
Conference
8th European Hypoxia Symposium: High altitude and isobaric hypoxia influence on human performance: science and practice, Police, Slovenia, 8 - 11 September 2016
Available from: 2016-12-22 Created: 2016-12-22 Last updated: 2016-12-22Bibliographically approved
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