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Acute Mountain Sickness, Hypobaria, Hypoxia and Exercise Duration All Differentially Affect Fluid Balance Hormones
Author(s) -
DiPasquale Dana,
Strangman Gary,
Harris N Stuart,
Muza Stephen
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.859.3
Subject(s) - hormone , hypoxia (environmental) , balance (ability) , affect (linguistics) , medicine , physiology , physical medicine and rehabilitation , chemistry , psychology , oxygen , organic chemistry , communication
Prior studies show that normobaric hypoxia (NH), hypobaric hypoxia (HH), and exercise (EX) contribute to acute mountain sickness (AMS) development. Body fluid changes are implicated in AMS etiology. While the role of fluid regulatory hormones has been intensively studied, we examined the effect of NH, HH, AMS and exercise on these hormones. Thirty‐six subjects participated in a partial repeated measures study, completing 2 of 6 conditions: 8 h exposure to HH (4400 m), NH, or normobaric normoxia (NN) crossed with moderate EX for 10 or 60 min. AMS symptoms (Environmental Symptoms Questionnaire) were measured during exposure. Venous samples were collected pre‐ and post‐exposure. We tested whether AMS+ (AMS‐C蠅0.7), NH, HH and EX duration predicted the change in plasma antidiuretic hormone (ADH), aldosterone (ALDO), Na and K in separate multiple linear regression analyses, accounting for variations in SpO 2 . Chi square analysis was used to determine if NH and HH differed from each other. See Figure.AMS+ was associated with changes in fluid balance hormones suggestive of fluid retention. This may have been driven by ADH since plasma sodium was lower in AMS+ compared to AMS‐. HH produced greater increases in ADH and ALDO suggesting a role for fluid retention in AMS severity. Paradoxically, long EX—which produces more severe AMS than short EX—did not suggest fluid retention caused by the ADH or ALDO. These results suggest that NH and HH produce different physiological responses and long EX may produce more severe AMS by mechanisms other than fluid retention. Supported by DoD W81XWH1020199. Author's views not Army or DoD.