The human thirst mechanism is not very good at telling us we need to drink. In long-distance running, athletes know that they must drink every 20 minutes or they will lose their pace because of dehydration and overheating. There are many drinks sold as exercise-enhancing fluids, but nothing has been shown to be any better than water for exercise lasting less than about 90 minutes. It is also important to realize that drinks containing caffeine may aggravate dehydration by their diuretic effect. They increase urine flow.
Alcohol is especially bad because it impairs heart action, and also is a diuretic.
Because this is a dangerous condition, a person thought to be having a heat illness should be taken to an emergency room or to a doctor's office immediately. Non-exertional heat illness usually occurs in elderly people who allow their living quarters to become too hot. In addition, some medical conditions which are associated with impaired sweat gland function, such as cystic fibrosis, make people susceptible to heat illness. Adequate fluid intake, ventilation, and early recognition of signs of heat illness should reduce the deadly toll that heat takes every year. All Rights Reserved.