RESPONSES OF AUTONOMIC NERVOUS-SYSTEM DURING ACCLIMATIZATION TO HIGH-ALTITUDE IN MAN

  • 1 January 1976
    • journal article
    • research article
    • Vol. 47  (10) , 1076-1079
Abstract
Sojourners (20), between the ages of 20-30 yr were studied to evaluate responses of the autonomic nervous system during acclimatization to high altitude. The respones measured consisted of heart rate (HR), blood pressure (BP), oral temperature (Tor), mean skin temperature (Tsk), cold pressor response (CPR), orthostatic tolerance to tilt and urinary catecholamines. The subjects were tested initially at Delhi (altitude 260 m) and, thereafter, on acute induction to an altitude of 3500 m periodically for 3 wk. For comparison, the same responses were studied on 10 acclimatized lowlanders (AL) who were staying at the same altitude for more than 1 yr and on 10 high-altitude natives (HAN). The studies showed a rise in HR, BP, Tor and urinary catecholamines, and a fall in Tsk, CPR and orthostatic tolerance immediately on arrival at HA, indicating a relative hyperactivity of the sympathetic system. After a stay of 1 wk, there was a gradual recovery in all the responses, though sympathetic hyperactivity was still maintained throughout the 3 wk of stay. In AL also there was a preponderance of sympathetic activity, though of relatively lesser magnitude than that seen in sojourners. In HAN, on the other hand, there was a relative parasympathetic predomination. In lowlanders, it may take more than 1 yr of stay at altitude for complete recovery of autonomic balance.

This publication has 0 references indexed in Scilit: