We’ve all had it happen—you’re working out and sweating hard, and those little sweat beads roll into your eyes. Next thing you know, your eyes are burning like hell.
But other times, you’re sweating just as hard, and you barely notice the sweat droplets dripping into your eyes. In those cases, you blink them away without a second thought.
So why does sweat burn your eyes so badly during some workouts, but not with others?
Well, it has nothing to do with the kind of workout you’re doing—it has everything to do with how you’re body is prepped before you start sweating.
We mean one simple thing: hydration.
Your sweat is composed of water, salt, and other minerals, according to Rayna Habash, M.D., an ophthalmologist and consultant for TopLine MD in Miami. It’s the salt content that can be the kicker when it comes to eye irritation.
“The amount of salt fluctuates with the amount of hydration we’ve had that day, which is why our eyes burn more at times than others,” she says.
If you’re more hydrated, your sweat will have a lower salt concentration, since the water levels will dilute it more. Less salt in your sweat means less burning when it gets into your sensitive eye tissue.
On the other hand, if you’re dehydrated, or even just not at your normal level of hydration, there will be a higher concentration of salt in your sweat. That makes your sweat more irritating.
Whether your sweat burns or not can be a handy signal of dehydration—and the good thing is, even though it’s uncomfortable, the irritation isn’t really doing any damage to your eye, Dr. Habash says.
So, what can you do to stop the burn?
The best thing you can do is play the preventive game: Make sure you’re adequately hydrated before you hit the gym. One way to do that is to gauge the color of your urine—shoot for a consistent color of clear straw or lighter, hydration expert Luke Pyror, Ph.D., C.S.C.S., told us in the past.
Plus, pay attention to other markers of dehydration, too. Hydration levels also affect your skin, so if you’re lacking on H20, you might be suffering from dryness, especially in the skin around your eyes.
Dry skin around your eyes can make the burning effect more pronounced, says Shilpi Agarwal, M.D., a family medicine physician in Los Angeles. That’s because you may have micro-tears from the dryness, which can sting with salty sweat.
So if you’re dealing with dry skin too, make sure you use a light moisturizer that’s formulated for the eye area, says Dr. Agarwal, and use it at night when it can soak into your skin more effectively.
Another preventive tool: Stay consistent with your exercise program, says Daren Garb, M.D., a family medicine physician at CareMount Medical in New York.
“As you get in better shape, the body becomes more efficient and will excrete less sodium, possibly explaining a variation in burning in the eyes,” he says.
If you’re experiencing the burn already, splash your face and eyes with cool water, Dr. Garb adds, which is best for getting the salty sweat out quickly.
By Elizabeth Millard