Abstract

Fluid and thermal balance is menaced when exercise of high intensity and long duration is performed in a hot, humid environment. Plasma volume reduction depends on exercise intensity (shift into active muscles) and the water loss due to sweating is mainly derived from the tissues. Thus drinking has no direct effect on the reduced plasma volume. Training and heat acclimation enhance the capacity of the body to maintain fluid and thermal balance within physiological limits. It is important for the athlete not only to train his body but also his drinking behaviour to prevent disturbance of the water balance. One best drink for all athletes does not exist. Personal preference might have a greater impact on the intended water supply during marathon running than the scientific recommended alternative. Maybe an idea for an applied research project. More fundamental research is needed to elucidate the mechanism of the performance reduction after dehydration. Verf.-Referat