. "5. Water Requirements During Excercise in the Heat." Nutritional Needs in Hot Environments: Applications for Military Personnel in Field Operations. Washington, DC: The National Academies Press, 1993.
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Nutritional Needs in Hot Environments: Applications for Military Personnel in Field Operations
FIGURE 5-1 Rectal temperatures, heart rates, metabolic rates, and weight losses of four highly trained endurance runners during mild treadmill exercise in dry heat, in wet heat, and in a cool ambient temperature. Subjects consumed lunch in the test environment between 4.0 and 4.5 hours. Values are means ± SE. SOURCE: Gisolfi et al. (1977), used with permission.
and Kerslake, 1964; Collins and Weiner, 1962; Nadel and Stolwijk, 1973). These subjects were highly trained and essentially heat acclimatized as a result of their training. Untrained or unacclimatized subjects would have considerably lower sweat rates and would experience much more physiological strain than was shown by these men.
Exercise Intensity and Training
Under constant environmental conditions, skin sweating is a linear function of heat production or exercise intensity (Nielsen, 1969). Training in a neu-