Abstract

The method of a negative energy balance, applied at an appropriate time and with a correct weight-reducing diet, did not adversely affect the physical fitness. Non compensated effort dehydration and thermal dehydration reduced the physical fitness: prolonged sauna was particularly harmful to endurance. The drop in physical fitness was caused by losses of water and inorganic components with sweat, in the first place of the electrolytes: sodium and potassium. Immediate compensation by administration of an nutritive isotonic beverage reduced the losses of effort sweat and macro- and microelements with sweat, this resulting in positive sodium and potassium balances. Compensation for the losses of water and inorganic components permitted the competitors to retain or even to improve their physical fitness, despite application of sauna. If the method of a negative energy balance for body weight regulation cannot be used or if body weight has to be reduced immediately before the start by about 2 , then sauna can be applied, provided that at least 1 h before the start the competitor ingests 1/2 l of a nutritive isotonic beverage in several small portions. Verf.-Referat