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| 2. |
- Engan, Harald K., et al.
(författare)
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The effect of climbing mount everest on spleen contraction and increase in hemoglobin concentration during breath holding and exercise
- 2014
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Ingår i: High Altitude Medicine & Biology. - : Mary Ann Liebert Inc. - 1527-0297 .- 1557-8682. ; 15:1, s. 52-57
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 3. |
- Lodin-Sundström, Angelica, et al.
(författare)
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Effects of warm-up on static apnea performance
- 2010
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Ingår i: Proceedings from the European Underwater Baromedical Society 36th Annual Meeting Istanbul, Turkey 14-18 Sept 2010.
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Konferensbidrag (refereegranskat)
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| 4. |
- Pernett, Frank, et al.
(författare)
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Spleen Contraction During Sudden Eupneic Hypoxia Elevates Hemoglobin Concentration
- 2021
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Ingår i: Frontiers in Physiology. - : Frontiers Media SA. - 1664-042X. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- The spleen contracts progressively during moderate normobaric hypoxia exposure of 20 min, which elevates hemoglobin concentration (Hb). However, acute hypoxia exposure could be shorter and more severe when oxygen systems fail during, e.g., high-altitude sky diving, aircraft cabin pressure drop, balloon flights, extreme altitude climbing, and in some maladies. We aimed to evaluate the speed and magnitude of spleen contraction during short exposure to extreme eupneic hypoxia and its subsequent recovery on oxygen. Eight female and seven male volunteers were exposed to normobaric hypoxia (10% oxygen) for 10 min during sitting rest, followed by 10 min on 100% oxygen. Heart rate (HR), arterial oxygen saturation (SpO(2)), and mean arterial blood pressure (MAP) were measured continuously. The spleen was measured via ultrasonic imaging every minute for volume calculations, and venous blood samples were drawn before and after exposure for hemoglobin concentration (Hb). Mean (SD) spleen volume was 279 (115) mL before exposure, 219 (75) mL (21% reduction; P = 0.005) at 3 min of exposure, and 201 (93) mL after 10 min exposure to hypoxia (28% reduction; P < 0.001). Hb was 138.8 (7.6) g center dot L-1 before and 142.9 (8.1) g center dot L-1 after 10 min of exposure (2.9% increase; P < 0.001). SpO(2) was 96.4 (1.7)% before exposure and 74.7 (8.4)% during the last minute of exposure (22.5% reduction; P < 0.001). HR increased from 80 (14) to 90 (17) bpm during exposure (12% increase, P < 0.05). MAP remained unchanged. After 10 min recovery on oxygen, values had been restored for spleen volume and Hb, while SpO(2) was higher and HR lower compared with before hypoxia exposure. We concluded that acute normobaric hypoxia of only 10 min caused significant spleen volume contraction with Hb increase. This rapid spleen response, evident already after 3 min of exposure, could have a protective effect during sudden exposure to severe hypoxia.
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| 5. |
- Rodríguez-Zamora, Lara, 1985-, et al.
(författare)
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Blood lactate accumulation during competitive freediving and synchronized swimming
- 2018
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Ingår i: Undersea & Hyperbaric Medicine. - : Undersea and Hyperbaric Medical Society, Inc.. - 1066-2936. ; 45:1, s. 55-63
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 9. |
- Schagatay, Erika, 1961-, et al.
(författare)
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Spleen Volume and Contraction During Apnea in Mt. Everest Climbers and Everest Base Camp Trekkers
- 2020
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Ingår i: High Altitude Medicine & Biology. - : Mary Ann Liebert Inc. - 1527-0297 .- 1557-8682. ; 21:1, s. 84-91
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Tidskriftsartikel (refereegranskat)abstract
- The human spleen can contract and transiently boost the blood with stored erythrocytes. We measured spleen volume and contraction during apneas in two groups, each containing 12 Caucasian participants (each 3 women): one group planning to summit Mt. Everest (8848 m; "Climbers") and another trekking to Everest Base Camp (5300 m; "Trekkers"). Tests were done in Kathmandu (1370 m) 1-3 days after arrival, before the Climb/Trek. Age, height, weight, vital capacity, resting heart rate, and arterial oxygen saturation were similar between groups (not significant). After 15 minutes of sitting rest, all participants performed a 1-minute apnea and, after 2 minutes of rest, 1 maximal duration apnea was performed. Six of the climbers did a third apnea and hemoglobin concentration (Hb) was measured. Three axial spleen diameters were measured by ultrasonic imaging before and after the apneas for spleen volume calculation. Mean (standard deviation) baseline spleen volume was larger in Climbers [367 (181) mL] than in Trekkers [228 (70) mL; p = 0.022]. Spleen contraction occurred during apneas in both groups, with about twice the magnitude in Climbers. Three apneas in six of the Climbers resulted in a spleen volume reduction from 348 (145) to 202 (91) mL (p = 0.005) and an Hb elevation from 147.9 (13.1) to 153.3 (11.3) g/L (p = 0.024). Maximal apneic duration was longer in Climbers [88 (23) seconds vs. 67 (18) seconds in Trekkers; p = 0.023]. We concluded that a large spleen characterizes Climbers, suggesting that spleen function may be important for high-altitude climbing performance.
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| 10. |
- Abrahamsson, Erik, et al.
(författare)
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A living based on breath-hold diving in the Bajau Laut
- 2014
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Ingår i: Human Evolution. - 0393-9375. ; 29:1-3, s. 171-183
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Tidskriftsartikel (refereegranskat)abstract
- 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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