What’s the sweatiest part of your body? Nope – it’s NOT your armpits. According to a new study, it’s your upper back. Why? Because sweat keeps you cool. Your upper back has the biggest expanse of sweat-producing skin and your arms and hunched-over body can’t get in the way of cooling evaporation.

Scientists say that when you do anything that’s physically demanding, your internal temperature starts to rise. To cool off, your body starts sweating. And when the liquid on your skin evaporates, it takes heat away with it. So, here’s how to take advantage of the sweat-evaporation cycle to keep yourself cool.

First: Don’t wipe yourself down! Sweat only helps cool your body when it evaporates off your skin so, wiping it off is counterproductive. But experts say it’s okay to towel off your forehead to keep the sweat from dripping in your eyes. Because the small amount of forehead sweat won’t do much to cool you off as it evaporates.

Another tip: Tuck in your shirt. Creating a gap between your shirt and skin creates a pocket of air which helps the sweat evaporate faster. And faster evaporation equals faster cooling.

Also: Drink enough water to replace what you sweat out. You should always drink enough water to keep your urine a light color.  The more dehydrated you are, the darker it’ll be. But if you usually exercise heavily, you need to estimate how much water you’re losing. Just hop on the scale before and after your exercise session.  That’ll give you an idea of how much replacement water you need to drink. Just remember: One pound is about 16 ounces of fluid.

Finally, if the most-sweaty part of the body is your upper back, what’s the least-sweaty? Your hands, fingers, and feet.