5 months ago

Drink up?


FEATURE In the middle of summer we’re advised to drink plenty of water, but some of us — especially dieters — can end up swigging between two to three litres of water a day. So is there a golden number? Louise Wates writes If you read my ‘from the editor’ column, you’ll know that I recently plodded the Race for Life 5 k. What I failed to mention was that from around 2.5 k — right up until the end — I had felt like throwing up. After crossing the finishing line, I was whisked away to the ambulance, retching loudly, where I was given water. The assumption was that I was dehydrated, even though overhydration can also be a problem for some runners (although more likely marathon runners than plodders like myself). But nobody asked me if I had drunk anything during the run. To be fair, my nausea probably was caused by dehydration and exertion. Not only had I cut my 5 k time by three minutes (woohoo!) but in the three hours before the run, I’d only taken a few sips of water — because I had suddenly, irrationally become nervous about needing the loo. It was a hot, muggy day, too. So, yes, I was foolish. But it did get me wondering about hydration and whether being told to drink can be a bit like being told to breathe. The NHS says we should all be drinking “plenty of water”, citing the Eatwell Guide in recommending six to eight glasses of fluid — albeit without specifying the size of a glass. It is also commonly said that by the time we feel thirsty we are already dehydrated and that, if exercising, just -2 per cent of body mass from fluid loss decreases performance — so no wonder that a bottle of water is considered essential gym gear. Dehydration and sporting performance Yet in 2013, when it comes to sports and performance, an Australian study concluded otherwise. Cyclists who were kept ‘blinded’ to their hydration status (i.e. they were given fluids intravenously and so could not tell if they were fully hydrated or not) experienced no drop in performance even when they were dehydrated to -3 per cent body mass. 1 Most of us, however, are sitting at a desk and are not elite athletes. So should we be glugging away to meet a two-litre target? 44 OPTIMUM NUTRITION | SUMMER 2018