Trail Running Tips for Staying Hydrated in the Heat

It’s beginning to feel a lot like summertime, and the trails are beckoning. But in a rush to play outside it’s easy to overlook preparation for running in high heat.

When the body’s temperature rises above 103 degrees, power and performance drop, and outdoor adventure can quickly turn into scary heat-related exhaustion or stroke if you’re not thinking ahead.

To learn what runners can do to stay hydrated and healthy before, during and after a summer run, we talked to Dina Griffin, a board-certified sport dietitian who works with endurance athletes of all ages in Boulder, Colorado. These tips are especially important on the trail, where runners can get dangerously far from necessary aid.

First, sodium: If you lose too much via sweating that’s not good. Sodium is responsible for controlling the total amount of water in the body. It also regulates blood volume and helps maintain muscle and nerve function.

But it’s important to note that your body’s sodium concentration can vary greatly from your buddy’s. Griffin tests her athletes and has found a large variance in the “saltiness” of athletes’ sweat.

“Then when we factor in one’s sweat rate [or how heavily a person perspires], this can dramatically affect hydration strategies,” she says. “It’s not usually possible to replace all fluid losses from sweat, especially for heavy sweaters, but a general fluid intake range is 16 to 32 ounces per hour.”

If you really want to fine-tune your hydration, learning your personal sweat rate in a variety of conditions is a great place to start.