Coping against acute stress generally involves with sudden increased oxygen demand,which can result in transient tissue hypoxia.Successful coping against unpredictable daily environmental changes,such as tissue hypoxia,muscular work,temperature shift,and mental challenge,ensures continuation of our wellbeing and survival.Baseline plasma dehydroepiandrosterone sulfate (DHEA-S) concentration has been found to closely associate with haman longevity and fitness.This endogenous steroid is known to decline with acute altitude exposure and advancing aging.In this view,we performed a series of human works to examine the role of DHEA-S in post-challenged recovery that potentially increases oxygen demand or reduces ambient oxygen.Our recent findings suggest that DHEA-S is consumed during recovery against external challenge,and low DHEA-S involves with poor adaptation.