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The effect of climbing mount everest on spleen contraction and increase in hemoglobin concentration during breath holding and exercise
Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande. LHL Health Röros, Norwegian Heart and Lung Patient Organization, Oslo, Norway.
Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande.
Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande.
Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
2014 (Engelska)Ingår i: High Altitude Medicine & Biology, ISSN 1527-0297, E-ISSN 1557-8682, Vol. 15, nr 1, s. 52-57Artikel i tidskrift (Refereegranskat) Published
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.

Ort, förlag, år, upplaga, sidor
2014. Vol. 15, nr 1, s. 52-57
Nyckelord [en]
Acclimatization, Apnea, Hematology, Hypobaric hypoxia, Red cell volume
Nationell ämneskategori
Idrottsvetenskap Hematologi Fysiologi
Identifikatorer
URN: urn:nbn:se:miun:diva-22041DOI: 10.1089/ham.2013.1061ISI: 000333464100008Scopus ID: 2-s2.0-84897141698OAI: oai:DiVA.org:miun-22041DiVA, id: diva2:720684
Anmärkning

Language of Original Document: English

Tillgänglig från: 2014-06-02 Skapad: 2014-05-30 Senast uppdaterad: 2018-01-11Bibliografiskt granskad
Ingår i avhandling
1. Cardiovascular, hematological and dietary means to cope with environmentally induced hypoxia in humans
Öppna denna publikation i ny flik eller fönster >>Cardiovascular, hematological and dietary means to cope with environmentally induced hypoxia in humans
2015 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Ort, förlag, år, upplaga, sidor
Östersund: Mid Sweden University, 2015. s. 87
Serie
Mid Sweden University doctoral thesis, ISSN 1652-893X ; 213
Nationell ämneskategori
Idrottsvetenskap Fysiologi
Identifikatorer
urn:nbn:se:miun:diva-25016 (URN)978-91-88025-01-2 (ISBN)
Handledare
Tillgänglig från: 2015-06-01 Skapad: 2015-06-01 Senast uppdaterad: 2018-01-11Bibliografiskt granskad
2. Initiation of spleen contraction resulting in natural blood boosting in humans
Öppna denna publikation i ny flik eller fönster >>Initiation of spleen contraction resulting in natural blood boosting in humans
2015 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

The spleen has been shown to contract in apneic situations in humans as well as in other diving mammals, expelling its stored red blood cell content into circulation. This natural blood boosting may increase the circulating hemoglobin concentration (Hb) by up to 10%, which would enhance the oxygen carrying capacity and likely increase performance. However, the triggers of this response in humans have not been fully clarified. Study I was therefore focused on the effect of hypoxia as a trigger of spleen contraction. It was found that 20 min of normobaric hypoxic breathing evoked a substantial reduction in spleen volume showing that hypoxia is an important trigger for spleen contraction. Knowing the role of hypoxia, Study II compared two different hypoxic situations – a 2 min apnea and 20 min normobaric hypoxic breathing – which resulted in the same level of arterial hemoglobin desaturation. Apnea evoked a twice as great spleen volume reduction, implying that variables other than hypoxia were likely involved in triggering spleen contraction. This may be hypercapnia which is present during apnea but not during normobaric hypoxic breathing. Study III therefore investigated the effects of breathing gas mixtures containing different proportions of CO2 prior to maximal apneas. Pre-breathing mixtures with higher percentages of CO2 resulted in greater spleen contraction, thus demonstrating hypercapnia's likely role as a trigger in addition to hypoxia. Study IV explored whether an all-or-nothing threshold stimulus for triggering spleen contraction existed, or if contraction was graded in relation to the magnitude of triggering stimuli. Exercise was therefore performed in an already hypoxic state during normobaria. Rest in hypoxia produced a moderate spleen volume reduction, with an enhanced spleen contraction resulting after hypoxic exercise, with a concomitant increase in Hb. This implies that spleen contraction is a graded response related to the magnitude of the stimuli. This could be beneficial in environments with varying oxygen content or work loads. Study V examined the possibility that spleen contraction is part of the acclimatization to altitude, during an expedition to summit Mt Everest. The long-term high altitude exposure, combined with physical work on the mountain, had no effects on resting spleen volume but resulted in a stronger spleen contraction, when provoked by apnea or exercise. This indicates that acclimatization to altitude may enhance the contractile capacity of the spleen, which may be beneficial for the climber. From these studies I concluded that hypoxia is an important trigger for spleen contraction but that hypercapnia also contributes in apneic situations. The spleen contraction likely provides a graded expulsion of erythrocytes in response to these stimuli, causing a temporary increase in gas storage capacity that may facilitate activities such as freediving and climbing. The storage of erythrocytes during rest serves to reduce blood viscosity, which would also be beneficial for the climber or diver. The human spleen contraction appears to become stronger with acclimatization, with beneficial effects at altitude. Such an upgraded response could be beneficial both in sports and diseases involving hypoxia.

Ort, förlag, år, upplaga, sidor
Östersund: Mid Sweden University, 2015. s. 87
Serie
Mid Sweden University doctoral thesis, ISSN 1652-893X ; 217
Nyckelord
Acclimatization, altitude, apnea, breath-hold diving, hemoglobin, hypercapnia, hypoxia, triggers
Nationell ämneskategori
Hälsovetenskaper
Identifikatorer
urn:nbn:se:miun:diva-25518 (URN)978-91-88025-10-4 (ISBN)
Handledare
Tillgänglig från: 2015-07-13 Skapad: 2015-07-13 Senast uppdaterad: 2017-06-15Bibliografiskt granskad

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