Effect of Cold Exposure,Exercise and High Altitude on Plasma Endothelin-1 and Endothelial Cell Markers in Man

Abstract

The aims were to examine the effect of cold exposure, exercise and high altitude on plasma concentrations of big endothelin-1, endothelin-1, von Willebrand factor and serum e-selectin in twenty five healthy male volunteers. Clinical evaluation and venesection were performed before and after 24 hours of low altitude mountaineering, exposure to temperatures of −18°C and +4°C and whilst ascending from sea level to an altitude of 5000m in the Karakoram. Plasma big endothelin−1, plasma endothelin−1 and serum soluble e-selectin concentrations were significantly elevated after two hours at −18°C (p<0.05, p<0.05 and p<0.01 respectively). At +4°C, plasma big endothelin-1 and endothelin−1 concentrations rose significantly after 5 hours (p<0.005 for both) but not after 2.5. hours. Low altitude mountaineering did not alter circulating marker concentrations. At high altitude, big endothelin−1 and endothelin−1 (p<0.01 for both) rose significantly at 2500m and initially at 5000m but returned to sea level values after prolonged exposure to 5000m. Serum e-selectin rose at all altitudes greater than sea level (p<0.05). In conclusion, exposure to high altitude, moderate cold or freezing temperatures, but not exercise, selectively activates endothelial cells increasing endothelin-1 production. Cold exposure may contribute to the observed increase in plasma endothelin- 1 in mountaineers at high altitude.