Strain Evaluation in Cold Climates During Exercise by the Cold Strain Index (CSI)

摘要

A new cold strain index (CSI), based on rectal temperature and skin temperature was recently suggested (Am. J. Physiol. 277:R556-R564, 1999). The purpose of this study was to validate CSI for exercising volunteers exposed to cool (0.0%) and moderately cold (-12.3 deg C) conditions. Eight volunteers walked on a level treadmill at a speed of 1.34 m/s for 15 min followed by sifting for 70 min. CSI evaluated all the exercise periods with negative calculated values, whereas the sifting periods were correctly assessed with positive values ranging from 0-10. Despite the cold exposure in this study, increased metabolic heat production masked the cold stress causing an elevation in core temperature and consequently negative values for CSI. Cold strain evaluation by CSI should be restricted to sedentary exposures, because during exercise in a cold environment, rectal temperature is the limiting indicator for cold strain assessment.