Water and electrolyte balance in workers exposed to a hot environment during their work shift∗

Abstract

We have investigated water and electrolyte balance in naturally heat-acclimatized workers having free access to water and performing light to moderate work in a warm environment during their regular 8 hour work shift. The study was conducted at the metal workshops of two plants located in the south of Israel in midsummer. Thirty-two workers were studied in Sdom, an extreme desert, and 13 in Beer Sheva, a semi-arid zone. The average WBGT at the work area ranged from 26°C at the beginning of the work shift to 29°C at the end in Sdom, and 24°C to 25°C, respectively, in Beer Sheva. Venous blood samples and body weights were taken before and after the work shifts. Three times during the work shifts, oral and skin temperatures were measured. The mean weighted skin temperatures increased 3.8°C in Sdom and 1.4°C in Beer Sheva during the work shifts, with a slight increase in oral temperatures. No weight loss was detected at the end of the work shifts. Haematocrit values decreased at the end of the work shifts while the other variables measured in the blood and serum were unchanged. Blood and plasma volumes increased during the work shifts. The data indicate that water and electrolyte balance was maintained. We conclude that when a naturally heat-acclimatized individual performs light to moderate work (choosing his own work regimen) during his work shift in a warm environment, while having free access to drinking water and electrolytes, he maintains water and electrolyte balance.

Keywords:

• Water
• Electrolytes
• Dehydration
• Acclimation

Notes

∗ This study was part of A. Gertner's Ph.D. research dissertation.

Additional information

Notes on contributors

A. GERTNER

Present address: The Johns Hopkins University, Division of Environmental Physiology, 615 N. Wolfe Street, Baltimore, Maryland 21205, U.S.A.