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How Much Water Should You Drink While Running a Marathon?

Don't Overdrink It: How to Hydrate For a Long Race

If you're training for a marathon or other long race, there are many things to think about: your training schedule, your race-day outfit, which shoes are right for you. Your hydration habits also need to be closely examined, says fitness expert and Pear Sports coach Matt Fitzgerald, author of The New Rules of Marathon and Half-Marathon Nutrition. Contrary to what many runners believe, drinking too much can hinder — not help — your run.

How have runners been hydrating wrong? "In the bad old days, a lot advice that runners got was to drink as much as possible, or to drink in order to completely offset sweat losses when doing long runs," Matt explains. "That turns out to be bad advice."

Research has shown that drinking more than your body needs doesn't help you, and in fact can hurt your race, Matt tells us. "When you force yourself to drink more than you're thirsty for or are comfortable drinking, you don't get any more benefit than you would than if you just drank by thirst or by comfort. In fact, the only change that can happen is that you have a much bigger risk of gastrointestinal distress," he says.

His advice: be mindful of your thirst and hydration needs, but don't force it. "Go ahead and trust your body's signals. That way you'll get as much fluid as your body can actually use and you won't increase the risk of having your whole run ruined by GI distress," he says. And come race day, don't try to stave off dehydration by drinking a lot before the race. "Human beings are not camels," Matt says. "If we drink more than our bodies actually need at that moment, we just end up going to the bathroom." If you want to avoid the long pre-race Porta Potty line or losing precious minutes relieving yourself during the race, stick to drinking just enough water to have to go to the bathroom once in the morning (after your initial wake-up bathroom trip) — about 15-20 ounces of fluid for most people, Matt advises.

Source: Getty
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