Proceedings of The Physiological Society

University of Oxford (2011) Proc Physiol Soc 23, PC339

Poster Communications

Effect of duration-of-stay at high altitude on plasma hormones and psychological variables

M. Sachidhanandam1, S. Arumugam2, S. Singh1, A. Salhan1, U. Ray1

1. Physiology, Defence Institute of Physiology and Allied Sciences, Delhi, India. 2. Defence Institute of Psychological Research, Delhi, India.

  • Plasma hormone levels in lowlanders and HA-natives.<\#13>

    Values are mean ± S.D. Level of statistical significance is p < .05. (*) LL at sea-level versus 1-month; (<\@>) LL at HA (1-month versus 6-month); (&) LL at sea-level versus 6-month at HA [General Linear Model -Multivariate analysis], ($) LL (1-month) versus HAN [unpaired t test], (#) LL (6-month) versus HAN [unpaired t test]. LL-lowlanders.

Acclimatization to hypobaric hypoxia of high-altitude (HA) is a complex process. Endocrine changes precede and bring about the necessary physiological changes. Lowlanders exposed to the ‘new’ HA environment also experience psychological changes - a stress that is known to affect plasma hormone concentrations. The aim of the study is to examine: plasma hormone and psychological changes in lowlanders during short- (1-month) and prolonged-stay (6-month) at HA in comparison to sea-level, and with HA-natives at HA. Correlation between psychological variables and plasma hormone levels at HA was also examined. Subjects were male volunteers between 20-50years of age. Lowlanders (n=25) were studied at sea-level, after 1-month stay at ~4500m, and after 6-month stay at ~3600m. HA-natives/Ladakhis (HAN, n=21) were studied at HA only. Psychological tests include: Memory(Digit-symbol); Depression(Beck-Depression-Inventory); Hopelessness(Beck-Hopelessness-scale); Loneliness(UCLA-Loneliness-scale). Plasma hormone levels were measured by enzyme immunoassay/enzyme-linked immunosorbent assay. Short-stay at HA causes changes in certain plasma hormone levels (cortisol, prolactin, T3, fT3, T4) and is associated with depression, loneliness and fear-of-death. Further stay at HA results in an increase in plasma T4. Memory, hopelessness and plasma TSH remain unaffected by HA stress in lowlanders. Variation in plasma hormone levels is present between lowlanders and HAN at HA. However, depression is present in both the groups at HA. Significant correlation was observed between depression/prolactin (r=-0.44); loneliness/freeT3 (r=-0.44) in HAN. The HA environment; rather than psychological factors appear to influence plasma hormone changes in lowlanders at HA. Also, short-stay at HA is associated with emotional stress and major hormone changes.

Where applicable, experiments conform with Society ethical requirements