Predicting sweat loss response to exercise, environment and clothing

Y. Shapiro, Kent B. Pandolf, R. F. Goldman

Research output: Contribution to journalArticlepeer-review

Abstract

Metabolic heat production (M), clothing heat transfer characteristics, and the environment dictate a required evaporative cooling (Ereq) from the body to maintain thermal balance. However, the maximal evaporative capacity (Emax) is dictated by vapor transfer properties of the clothing and environment. Relationships between metabolic load, environmental conditions, clothing and sweat loss were studied in 34 heat-acclimatized males categorized into four groups (eight, eight, eight, and ten subjects) and exposed to various environmental conditions (ambient temperature, 20-54‡ C, and relative humidity, 10-90%), three levels of metabolic rate (resting; walking 1.34 m·s-1, level; or walking 1.34 m·s-1, 5% grade) while wearing various clothing ensembles (shorts and T-shirts, fatigues, fatigues plus overgarment, or sweat suit). Individual groups were not exposed to all combinations. Exposures lasted 120 min: either 10 min rest - 50 min exercise - 10 min rest - 50 min exercise, or 120 min at rest. Physiological measurements included heart rate, rectal temperature, mean skin temperature, energy expenditure and sweat loss (δmsw). Emax and Ereq were calculated from environmental conditions, metabolism, clothing insulation and permeability. The ratio Ereq/δmsw was found to correlate with Emax and not with M. The predictive equation for sweat loss was: δmsw=18.7×Ereq×(Emax)-0.455 within the limits 50<Ereq<360; W·m-2 and 20<Emax<525; W·m-2. This formula predicts sweat loss for specific work loads, climates and clothing ensembles.

Original languageEnglish
Pages (from-to)83-96
Number of pages14
JournalEuropean Journal of Applied Physiology and Occupational Physiology
Volume48
Issue number1
DOIs
StatePublished - Feb 1982
Externally publishedYes

Keywords

  • Heat transfer
  • Humid and dry heat
  • Maximal evaporative capacity
  • Required evaporative cooling
  • Sweat loss

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