Yes, you do sweat when you swim. Even though you’re surrounded by water, your body still produces sweat to regulate its temperature. You just don’t notice it because it mixes instantly with the water.
Why Do You Sweat When You Swim?
Sweating is your body’s natural cooling system. Whenever you exercise, whether running, cycling, or swimming, your muscles generate heat. To stop your core temperature from rising too high, your body releases sweat. This process is called thermoregulation, and it happens in water just like it does on land.
Why You Don’t Feel Sweat in the Pool
There are two main reasons:
1. Water washes sweat away instantly
In a pool or open water, sweat doesn’t build up on your skin—it dissolves immediately into the surrounding water.
2. Water cools your skin
Water conducts heat away from your body much faster than air, so you feel cooler, even when your body is still producing sweat.
Do Swimmers Sweat as Much as Runners?
Usually, swimmers sweat slightly less, but still a significant amount. Water helps cool the body faster, so the body may not need to sweat as aggressively, but during intense sessions, sweat loss can still be high. Some athletes can lose litres of fluid per hour through sweat during exercise.
Can You Get Dehydrated From Swimming?
Yes, and this is where people get caught out. Because you don’t feel sweaty, it’s easy to underestimate fluid loss. Many swimmers don’t drink enough during sessions, and so they finish their workouts dehydrated, only realising afterwards when they feel thirsty, tired or have a headache.
Does Water Temperature Affect Sweating?
Absolutely. Warm pools will give you more sweating. Cool water means sweating less noticeable, but still happens. When you train harder, that increases the amount of sweat regardless of the temperature of the pool. Even in cold water, your body still produces heat internally and needs to regulate it.
Do You Sweat More in a Pool or the Sea?
There’s no huge difference in sweating itself, but saltwater can make dehydration feel worse. You’ll also find that open water swims often last longer so you may experience more total fluid loss.
FAQ Section
Do you sweat in cold water?
Yes. Even in cold water, your body produces heat during exercise, so sweating still occurs.
Why don’t I feel sweaty after swimming?
Because sweat mixes instantly with water, so it never builds up on your skin.
Can you sweat while underwater?
Yes. Sweat glands still function underwater, but the sweat just disperses immediately.
Should swimmers drink water?
Definitely. Even if you don’t feel sweaty, you’re still losing fluids.
Are pools dirty from sweat?
Sweat as a substance is a mixture of salt, sugar and ammonia. Fortunately, chlorinated water is more than capable of neutralising bacteria that can form as a result. As we mentioned in other blog posts though, if your pool smells too strongly of chlorine, it is likely a dirty pool. Clean pools rarely smell of anything at all.
There you have it. We hope we’ve made a good attempt at explaining this rather unusual but valid question.