Assessment of heat tolerance for post exertional heat stroke individuals.
BACKGROUND
The aim of this study was to evaluate the heat tolerance test, which was performed by individuals with high risk for heat injuries, for exposure duration and climatic conditions.


METHODS
Nineteen young (19+/-1 yr) post heat stroke males performed 2 separate tolerance tests consisting of identical treadmill walking (5km.h-1, 2% grade) for 120 min during hot (40 degrees C, 40%RH) and comfort (20 degrees C, 50%RH) climate conditions. Physiological monitoring included rectal temperature (Tre), heart rate (HR), skin temperature and sweat rate (msw). Concomitantly, strain evaluation was assessed by the physiological strain index (PSI) and the cumulative heat strain index (CHSI).


RESULTS
14 subjects were categorized as heat tolerant (HT) and 5 subjects as heat intolerant (HI). The comfort tolerance test was found as irrelevant for heat intolerance assessment. PSI after 60 min (PSI60) was unable to predict PSI after 120 min (PSI120) whereas there was not a high enough correlation between CHSI60 and CHSI120.


CONCLUSIONS
It was concluded that tolerance to heat must be tested during heat stress and the test duration cannot be shorter than 120 min.
Moran
Daniel S
DS
Heller Institute of Medical Research, Sheba Medical Center, Tel Hashomer 52621, Israel. dmoran@sheba.health.gov.il
Heled
Yuval
Y
Still
Lawrence
L
Laor
Arie
A
Shapiro
Yair
Y
D000328:Adult; D001831:Body Temperature; D015444:Exercise / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D018883:Heat Stroke / Q000503:physiopathology*; D006358:Hot Temperature; D006801:Humans; D008297:Male; D005082:Physical Exertion / Q000502:physiology*; D013542:Sweat