Effect of post-hypoxic acclimatization on extremity temperature during exposure to acute cold stress in man.

Twelve male volunteers aged 20-28 yr, who were physically fit for high altitude duties were studied. Recordings of oral temperature, mean skin temperature, extremity temperature, O2 consumption and heart rate were taken in a thermoneutral room (26 degrees +/- 2 degrees C) and cold room (6 degrees-8 degrees C) initially; after 4 wk stay at 3353 m (502 mm Hg); again after 4 wk at 4115 m (455 mm Hg); and finally after return to Delhi (740 mm Hg). The oral temperature, mean skin temperature, oxygen consumption and heart rate did not show any significant difference from their initial sea level values recorded in the thermoneutral room or the cold room. It may be concluded that our subjects did not exhibit any degree cold acclimatization when retested at sea level. A significant elevation (P less than 0.001) of extremity temperature observed during retest in cold might be due to some degree of vasodilatation through relaxation of constrictor tone that might have taken place during exposure to hypoxia at high altitude.