. "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
There are influences from increments in plasma volume and tonicity but compared to an elevation in core body temperature, they are rather small.
DR. GISOLFI: I wanted to make a comment back on sweating, though, on how sweating changes with acclimatization. You must be careful in your interpretation of the literature because if you just look at total body sweating, you get very misleading results.
The magnitude of sweating is related to the rise in body temperature. So if you heat acclimatize a soldier, you will observe increases in sweating early in the process. However, at the end of acclimatization, if you are looking at just total body sweating, you are actually looking at a small rise in body temperature and the same sweating response. The important point is that for a given rise in core temperature, you do have more sweating.
PARTICIPANT: I would like to go back to this prediction equation briefly. That did not take into account obesity or any kind of differences in adiposity amongst individuals; is that right?
DR. GISOLFI: That's correct. The heat required term is based on metabolic rate, which takes body weight into account. Adiposity is not specifically addressed by this equation.
PARTICIPANT: This was done in a military population?
DR. GISOLFI: This was done in the military population, to my knowledge. It is only body weight that is taken into consideration.
PARTICIPANT: So this is a specialized group, then, so it would not necessarily fit across the board; is that what you are saying then?
DR. GISOLFI: Yes. I would also say that I am not familiar with any literature that has indicated that an increase in adiposity reduces the sweating response.
PARTICIPANT: In fact, you showed your men had half the body fat of women and yet their ability to lose heat was equal so adiposity may or may not make any difference, probably not.