# Why Does Sweat Sting Your Eyes? **URL:** \ **Category:** Factual Questions\ **Created:** [August 10, 2008, 8:22pm UTC](https://boards.straightdope.com/t/why-does-sweat-sting-your-eyes/459524 "2008-08-10T20:22:44Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![ralph124c](https://avatars.discourse-cdn.com/v4/letter/r/8797f3/32.png) [@ralph124c](https://boards.straightdope.com/u/ralph124c)\ **Post date:** [August 10, 2008, 8:22pm UTC](https://boards.straightdope.com/t/why-does-sweat-sting-your-eyes/459524/1 "2008-08-10T20:22:44Z")
Isn’t sweat essentially the same salt content of tears? Why does sweat make your eyes sting so bad? I s sweat more concentrated? ---
**Author:** ![Marley23](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Marley23](https://boards.straightdope.com/u/Marley23)\ **Post date:** [August 10, 2008, 8:28pm UTC](https://boards.straightdope.com/t/why-does-sweat-sting-your-eyes/459524/2 "2008-08-10T20:28:34Z")
I’m moving this over to GQ. Not to speculate, but I have been told that sweat is chemically similar to urine - the same thing, really - so with that amount of salt I think the stinging is no surprise. ---
**Author:** ![Patty\_O\_Furniture](https://avatars.discourse-cdn.com/v4/letter/p/96bed5/32.png) [@Patty\_O\_Furniture](https://boards.straightdope.com/u/Patty_O_Furniture)\ **Post date:** [August 10, 2008, 9:35pm UTC](https://boards.straightdope.com/t/why-does-sweat-sting-your-eyes/459524/3 "2008-08-10T21:35:16Z")
[QUOTE=Marley23] Not to speculate, but I have been told that sweat is chemically similar to urine - the same thing, really - so with that amount of salt I think the stinging is no surprise. [/QUOTE] If true, eww. ---
**Author:** ![levdrakon](https://avatars.discourse-cdn.com/v4/letter/l/49beb7/32.png) [@levdrakon](https://boards.straightdope.com/u/levdrakon)\ **Post date:** [August 10, 2008, 9:38pm UTC](https://boards.straightdope.com/t/why-does-sweat-sting-your-eyes/459524/4 "2008-08-10T21:38:14Z")
I’ve tasted my own sweat, and it doesn’t taste saltier than sea water. You can open your eyes in sea water. ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [August 10, 2008, 9:43pm UTC](https://boards.straightdope.com/t/why-does-sweat-sting-your-eyes/459524/5 "2008-08-10T21:43:32Z")
[QUOTE=levdrakon] I’ve tasted my own sweat, and it doesn’t taste saltier than sea water. You can open your eyes in sea water. [/QUOTE] …and it _stings_ when you do it. So I’m not sure what point you’re trying to make. ---
**Author:** ![levdrakon](https://avatars.discourse-cdn.com/v4/letter/l/49beb7/32.png) [@levdrakon](https://boards.straightdope.com/u/levdrakon)\ **Post date:** [August 10, 2008, 10:15pm UTC](https://boards.straightdope.com/t/why-does-sweat-sting-your-eyes/459524/6 "2008-08-10T22:15:00Z")
[QUOTE=Frylock] …and it _stings_ when you do it. So I’m not sure what point you’re trying to make. [/QUOTE] Uh, I guess my point would be it doesn’t sting my eyes, but sweat does. ---
**Author:** ![kniz](https://avatars.discourse-cdn.com/v4/letter/k/c37758/32.png) [@kniz](https://boards.straightdope.com/u/kniz)\ **Post date:** [August 10, 2008, 10:23pm UTC](https://boards.straightdope.com/t/why-does-sweat-sting-your-eyes/459524/7 "2008-08-10T22:23:19Z")
Urine and sweat both are mostly water and contain salt. This is also true of sea water. It is the salt that stings your eyes. Perhaps sweat contains more salt than sea water. 😛 ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [August 10, 2008, 10:25pm UTC](https://boards.straightdope.com/t/why-does-sweat-sting-your-eyes/459524/8 "2008-08-10T22:25:02Z")
[QUOTE=levdrakon] Uh, I guess my point would be it doesn’t sting my eyes, but sweat does. [/QUOTE] Ah, I see. I didn’t realize you were trying to imply that seawater doesn’t sting your eyes.\* I get it now. -FrL- - :eek: It _fhurts_ when I do it. Like enough to make me useless to the world for a few minuts. ---
**Author:** ![lawoot](https://avatars.discourse-cdn.com/v4/letter/l/35a633/32.png) [@lawoot](https://boards.straightdope.com/u/lawoot)\ **Post date:** [August 11, 2008, 6:04am UTC](https://boards.straightdope.com/t/why-does-sweat-sting-your-eyes/459524/9 "2008-08-11T06:04:47Z")
Perhaps the stinging isn’t from the sweat itself, but from the contaminents that may be on the skin - dirt, makeup, etc - that end up IN the sweat. ---
**Author:** ![cainxinth](https://avatars.discourse-cdn.com/v4/letter/c/7bcc69/32.png) [@cainxinth](https://boards.straightdope.com/u/cainxinth)\ **Post date:** [August 11, 2008, 6:06am UTC](https://boards.straightdope.com/t/why-does-sweat-sting-your-eyes/459524/10 "2008-08-11T06:06:42Z")
Tears and sweat are mostly just water and salt with trace amounts of urea and other compounds and minerals, but not the same salts and not in the same amounts. The composition of tears protects your eyes by lubricating them and keeping them moist. When a liquid covers your eyes that doesn’t closely match that composition your eyes aren’t properly protected and irritation can occur. The lack of protective mucus and proteins and other ingredients is part of the cause of irritation, but mostly it’s due to changes in the salts. Some people can open their eyes in the ocean or even swimming pools or get sweat in them without any problems, others can’t. I suppose it all depends on the health and sensitivity of your eyes and the particular composition of your ocean, pool, or sweat. ---
**Author:** ![Siam\_Sam](https://avatars.discourse-cdn.com/v4/letter/s/d78d45/32.png) [@Siam\_Sam](https://boards.straightdope.com/u/Siam_Sam)\ **Post date:** [August 11, 2008, 6:14am UTC](https://boards.straightdope.com/t/why-does-sweat-sting-your-eyes/459524/11 "2008-08-11T06:14:55Z")
[QUOTE=levdrakon] I’ve tasted my own sweat, and it doesn’t taste saltier than sea water. You can open your eyes in sea water. [/QUOTE] This is a question I’ve always had. Myself, I simply cannot open my eyes in any water – seawater, fresh water, swimming pools, nowhere. But I’ve always wondered about all of these movies and TV shows where the actors are able to do it seemeingly effortlessly. Are my eyes just overly sensitive? They are in general, so maybe regarding water, too? I see **cainxinth’s** post above, but I see so many people who can do it, I have to wonder. ---
**Author:** ![Capt.Ridley\_s\_Shooting\_Party](https://avatars.discourse-cdn.com/v4/letter/c/cc9497/32.png) [@Capt.Ridley\_s\_Shooting\_Party](https://boards.straightdope.com/u/Capt.Ridley_s_Shooting_Party)\ **Post date:** [August 11, 2008, 1:29pm UTC](https://boards.straightdope.com/t/why-does-sweat-sting-your-eyes/459524/12 "2008-08-11T13:29:19Z")
It takes a few hours of swimming for my eyes to properly adjust to seawater. It’s agony at first. ---
**Author:** ![Pedro](https://avatars.discourse-cdn.com/v4/letter/p/919ad9/32.png) [@Pedro](https://boards.straightdope.com/u/Pedro)\ **Post date:** [August 11, 2008, 1:57pm UTC](https://boards.straightdope.com/t/why-does-sweat-sting-your-eyes/459524/13 "2008-08-11T13:57:21Z")
I’ve noticed that seawater spray or droplets on the eyes stings a lot but opening them underwater in the sea is not painful after some initial discomfort. But I wonder if it’s healthy because it does tend to make the eyes feel sensitive and sore.