ISSN:
1432-1254
Keywords:
Key words Heat stress
;
Rectal temperature
;
Skin temperature
;
Clothing insulation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geography
,
Physics
Notes:
Abstract This study evaluates the effect of different levels of insulation on esophageal (T es) and rectal (T re) temperature responses during and following moderate exercise. Seven subjects completed three 18-min bouts of treadmill exercise (75% VO2max, 22°C ambient temperature) followed by 30 min of recovery wearing either: (1) jogging shoes, T-shirt and shorts (athletic clothing); (2) single-knit commercial coveralls worn over the athletic clothing (coveralls); or (3) a Canadian Armed Forces nuclear, bacteriological and chemical warfare protective overgarment with hood, worn over the athletic clothing (NBCW overgarment). T es was similar at the start of exercise for each condition and baseline T re was ∼0.4°C higher than T es. The hourly equivalent rate of increase in T es during the final 5 min of exercise was 1.8°C, 3.0°C and 4.2°C for athletic clothing, coveralls and NBCW overgarment respectively (P〈0.05). End-exercise T es was significantly different between conditions [37.7°C (SEM 0.1°C), 38.2°C (SEM 0.2°C and 38.5°C (SEM 0.2°C) for athletic clothing, coveralls and NBCW overgarment respectively)] (P〈0.05). No comparable difference in the rate of temperature increase for T re was demonstrated, except that end-exercise T re for the NBCW overgarment condition was significantly greater (0.5°C) than that for the athletic clothing condition. There was a drop in T es during the initial minutes of recovery to sustained plateaus which were significantly (P〈0.05) elevated above pre-exercise resting values by 0.6°C, 0.8°C and 1.0°C, for athletic clothing, coveralls, and NBCW overgarment, respectively. Post-exercise T re decreased very gradually from end-exercise values during the 30-min recovery. Only the NBCW overgarment condition T re was significantly elevated (0.3°C) above the athletic clothing condition (P〈0.05). In conclusion, T es is far more sensitive in reflecting the heat stress of different levels of insulation during exercise and post-exercise than T re. Physiological mechanisms are discussed as possible explanations for the differences in response.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s004840050110
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