How To Hydrate

WHEN to drink and what to drink? These concerns preoccupy the thoughts of many a distance runner and it can be baffling to decipher the mixed messages of sports drink manufacturers (who insist we should consume more fluids) and sports scientists (who often encourage us to drink less).

Confused? Don’t worry, we spell out the rules of fluid intake as determined by the leading experts:

MILD HYDRATION CAN BOOST PERFORMANCE

A report by New Zealand sport scientists suggested that a 3% drop in body weight through fluid loss doesn’t slow down athletes, while a 2012 paper in the Clinical Journal of Sports Medicine found that elite runners in the heat of the Dubai Marathon recorded fluid losses of almost 10%, yet still their finishing times were unaffected.

How is this the case? John Brewer, professor of applied sport science at St Mary’s University, Twickenham, says that “tactical dehydration” is a growing phenomenon among endurance runners, triathletes and cyclists, at club and elite level.

“Each litre of fluid lost equates to approximately 1kg of body weight,” Brewer explains. “Carrying around less weight has a positive impact on endurance performance, so people train their bodies to cope with dehydration.”

HOW MUCH FLUID DO YOU NEED?