Recent heat and cold strain predictive indices

Recent heat and cold strain predictive indices have been developed. The physiological strain index (PSI), based on rectal temperature and heart rate, is capable of indicating heat strain online and analyzing existing databases. Six studies, containing eight databases were analyzed to evaluate PSI for different climates, hydration levels, clothing, exercise intensities, gender, and aging. PSI was capable of differentiating (p<0.05) between all of these conditions and some combinations of conditions. Our cold strain index (CSI), based on core and mean skin temperatures, is able to indicate cold strain in real time and analyze existing databases. There studies containing three databases were analyzed in order to evaluate CSI for different cold air and cold-water immersion conditions. CSI differentiated (p<0.01) between the conditions for two of these three databases. However, further study is required to possibly adjust CSI for a wider range of cold air and water temperatures, and to consider the effects of physical exercise. Both PSI and CSI rate heat and cold strain on a universal scale of 0-10. Both indices have the potential to be widely accepted and used universally for many scenarios.