Effectiveness of an air-cooled vest using selected air temperature and humidity combinations

Aviat Space Environ Med. 1987 Feb;58(2):119-24.

Abstract

We evaluated the effectiveness of an air-cooled vest in reducing thermal strain of subjects exercising in the heat (49 degrees C dry bulb (db), 20 degrees C dew point (dp] in chemical protective clothing. Four male subjects attempted 300-min heat exposures at two metabolic rates (175 and 315 W) with six cooling combinations--control (no vest) and five different db and dp combinations. Air supplied to the vest at 15 scfm ranged from 20-27 degrees C db, 7-18 degrees C dp; theoretical cooling capacities were 498-687 W. Without the vest, endurance times were 118 min (175 W) and 73 min (315 W). Endurance times with the vest were 300 min (175 W) and 242-300 min (315 W). The five cooling combinations were similarly effective in reducing thermal strain and extending endurance time, although there was a trend for the vest to be more effective when supplied with air at the lower dry bulb temperature. At 175 W, subjects maintained a constant body temperature; at 315 W, the vest's ability to extend endurance is limited to about 5 hours.

MeSH terms

  • Adult
  • Body Temperature
  • Heart Rate
  • Hot Temperature*
  • Humans
  • Humidity*
  • Male
  • Military Personnel
  • Physical Endurance
  • Physical Exertion
  • Protective Clothing*
  • Stress, Physiological / prevention & control
  • Sweating