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Don’t drink too much

It’s actually possible to drink too much fluid, although this is uncommon. More of a risk during marathons and triathlons, athletes who consume a lot of fluid (even sports drinks), but not enough sodium can develop a potentially life-threatening condition called hyponatremia. (A women died of it during the 2002 Boston Marathon.)

Symptoms include bloating, nausea, confusion, disorientation, and seizures.

But really, over hydration is “rare,” says Clark. “Most people don’t drink enough.”

Next: Pack in some protein and carbs