The athlete's guide to water

Drinking plenty of water can help you function at your best because when you're dehydrated, "the blood is more viscous, which means less oxygen is reaching your muscles," explains Matt Berenc, CSCS, director of education at the Equinox Fitness Training Institute. Here, what you can (and cannot) expect from you next tall glass.

It can keep headaches at bay.

One study found that drinking more H20 daily improved head pain and quality of life in migraine sufferers.

It can prevent cramps.

Sip water two hours pre-workout to avoid sidelining stitches and muscle spasms.

It’s not a weight loss elixir.

The energy required to sink cold water to body temperature can increase metabolic rate, but even chilly sips will likely have no effect on weight loss, says Marie Spano, RD, a sports nutritionist based in Atlanta.

It’s not always enough.

If you’re exercising in the heat or for long periods of time, you’ll sweat out both water and electrolytes. Eating foods rich in minerals like magnesium, potassium, and calcium will keep your muscles feeling strong throughout the entire session.

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