The guy next to me on the bike yesterday morning was working like Lance Armstrong in training; he had laid towels on the floor to absorb the impressive perspiration he was generating.
He shouted over to me: “I’m hitting it hard to cleanse out the toxins from last night. Too much Captain Morgan and Buffalo wings, ya know?”
“Really,” I said.
“Actually, I’m a dermatologist, and sweat does not contain any toxins,” I said to myself so that he could not hear. (Gym decorum dictates men do not correct men in the middle of a workout — especially if prefaced by “Actually, I’m a dermatologist”). I left him to his aerobics and wrote this post in my head while I finished mine.
You might not want to believe me, but it’s fact: you cannot sweat out toxins. Sweat is composed of 99% water and a tiny percent of salt, urea, proteins and carbohydrates. Salt, proteins and carbohydrates are natural. Urea is a by-product of protein metabolism and is non-toxic. It’s regulated to keep your blood at a healthy pH. Most excess urea is eliminated in urine (hence the name) and a small amount is in sweat.
Toxins like mercury, chemicals, alcohol, drugs, and spicy BBQ sauce are eliminated by your liver and intestines.
Sweat glands, all 2.6 million of them, regulate your temperature — they’re not designed to expel toxins.
The primary ingredient in sweat is pure water. The water evaporates from your skin, cooling you. Excess sweating doesn’t eliminate excess salt or help hangovers. By forcing your body to copiously perspire, you’re only forcing your kidneys to save water (and ironically actual toxins) elsewhere. The water that ends up in the towel on the floor is the precious water you needed to stay hydrated, not a puddle of poison.
In some ways sweat is the opposite of toxic, it’s a vital fluid. When you are working out hard, replace it. I recommend water, not Captain Morgan Rum.