Enhancement of cold-induced vasodilatation following acclimatization to altitude.

The present study evaluated the effect of high-altitude acclimatisation on the cold-induced vasodilatation (CIVD) response. A group of highly trained mountaineers (N = 9; Alpinists) were tested before and after a 3 week high-altitude Himalayan expedition (altitude ranging from 3,985 to 6,828 m). A control group (N = 7) with no mountaineering experience was tested at the same time points. During each test, subjects first immersed their hand to the styloid process in 37 degrees C water for 5 min and then in 10 degrees C water for 30 min. Upon completion of the hand immersion, the same procedure was repeated for the foot. Skin temperature of the pads of all immersed digits was measured throughout the immersion and for 10 min following the immersion. In the Alpinists, a significant increase in amplitude of CIVD and absolute maximum finger skin temperature during immersion was observed in the hand post-expedition. For the foot, peak time of CIVD was significantly shorter in the Alpinist group, and there were significant increases in minimum and maximum toe skin temperature during CIVD, mean toe skin temperature during immersion, absolute minimum and maximum toe skin temperature during immersion, and absolute amplitude during immersion. The results demonstrate a significant enhancement of the CIVD response as a consequence of a brief high altitude acclimatisation, and that these changes were especially prominent in the toes.