To the Editor.—
Regarding the article "Losing Weight Through Exercise" (1980;244:377), in the authors' disparagement of "effortless weight reduction" by methods that cause increased water loss, they make the often repeated misleading statement that "body weight may be temporarily reduced until rehydration occurs." This implies that there is no caloric consumption involved in the water loss. The same statement could be made for the weight loss incurred by a marathon runner during a race and his subsequent "weight gain" after rehydration.The fact overlooked by most people who attempt to debunk saunas and other devices that cause enhanced sweating is that the water does not just "leak out" of the body. Sweating is a part of the complex thermoregulatory process of the body involving substantial increases in heart rate, cardiac output,1,2 and metabolic rate,3-4 and consumes considerable energy.In a sauna, heat is absorbed by the subject from