We drink 50/50 Gatorade and water on summer hikes precisely to avoid getting sick. A hard-learned lesson as early on in our Shenandoah hiking adventures a friend and I each drank a gallon of water on a steep 9-mile hike on a 90-degree humid day.

We were sweating so much we didn't pee any of that water out.

Afterward, she was quite nauseous and had a severe headache. I was fine but we learned about hyponatremia and, as I noted, ever since we go 50/50 on pure water and Gatorade.

We also carry a salty snack.