The first time I teetered on the verge of dehydration was on a mid-July day in South Carolina on vacation. I was rollerblading (yes, rollerblading, don’t judge) around the neighborhood I was visiting, just cruising around, nothing crazy, so I didn’t bring any water with me. About an hour in, I suddenly felt dizzy, like, “I’m not sure I should be rollerblading” dizzy. I sat down under a tree in the shade for 15 minutes, got my bearings, and very easily rolled home to enjoy a long stretch of A/C and sweet tea.
The fact is you don’t have to be pushing hard or going long to succumb to dehydration. “It’s normal to experience mild dehydration during exercise,” says Rob Pickels, physiology director at CU Sports Medicine and Performance Center in Boulder, Colorado, especially if you’re in the heat and sweating. “However, prolonged moderate dehydration or severe dehydration can be detrimental to your health; especially your kidney function. We all know that when we’re thirsty or our mouth is parched, it’s a good time to take a drink,” he says. But there are less obvious signs that you’re well on your way to serious dehydration. Here’s what Pickels warns to watch for.
We know heart rate goes up with intensity and that it will tend to drift with long exercise, especially in the heat. However, if you’re seeing heart rates that are 15- to 20-beats higher than you’d expect, it could be your heart is compensating for reduced blood volume—dehydration—by beating faster.
You know how your head swims a bit when you suddenly stand from a sitting position? It’s called postural hypotension, and it’s the result of blood not reaching your head quickly enough as you change positions thanks to low blood volume. If you start feeling that while you’re exercising when you change positions, that could be a sign of dehydration.
Technically called “decreased skin turgor”—when the skin on the back of your hand doesn’t snap back from being pinched—saggy skin is a sign you need more fluids stat. “With normal hydration, the pinched skin should return back to normal essentially immediately,” says Pickels. With moderate to severe dehydration it will be slow to return. “Try it now (I know you are) by pinching your skin for two to three seconds and then letting go. That’s your baseline,” he says. If it’s slow to rebound during exercise, you’re dangerously dehydrated.
What’s That Smell?
If you take a nature break and it smells like you’ve wandered into a bus station bathroom, that’s another good sign to drink more says Pickels. “A strong urine smell can be a sign of dehydration.” Of course, it’s still good that you have to pee at this point, since once you hit severe dehydration urine production decreases dramatically. Avoid slipping into that next stage by boosting your fluid intake as soon as possible.
This article was originally published by our partners at Bicycling.