If you work out in the gym or you're a regular jogger, you probably drink a lot of fluids during and after exercise. It's seems a natural thing to rehydrate the body and replace the fluids lost during exercise - but, if done to excess, it could be dangerous practice. At least seven athletes have died after drinking too much liquid, and another 250 have needed hospital treatment.
The practice is more to do with fashion rather than science; in fact, there is no science at all to support it. Until the late 1960s, athletes were advised not to drink during exercise, as it would impair performance. Then, in 1969, a landmark study, entitled 'The danger of an inadequate water intake during marathon running', was published - even though it neither looked at the dangers, nor did it base its findings on marathon races. Indeed, the article confirmed the ancient lore that the dehydrated runners won the race.
But the ill-titled piece was enough to spawn an industry of articles and papers that extolled the importance of drinking plenty of fluids - water or sports drinks - during and after exercise. Most were funded by a growing sports-drinks industry.
So what to do? As usual, common sense should prevail, and you should drink if you're thirsty, but don't try to replace your lost body weight with liquid, as is suggested - it just might kill you.
(Source: British Medical Journal, 2003; 327: 113-4).