Why does sweat remove the oil from my face?

Question

my skin is kinda oily but when i sweat in the heat, mt skin becomes oil free why?

Answer 1

The oil on your skin is from oil glands in your skin. It is the body's way of protecting the outer skin layer. The oil lubricates your skin so that it is water proof and doesn't dry and crack. when you sweat, the body is working to cool itself. The water emitted thought your sweat glands evaporates. The evaporation disperses heat by transferring the heat to the water which becomes vapor.

The oil is removed because it runs off of your body with the beads of sweat. The oil is absorbed with your sweat into your clothing, and a towel if you are drying yourself. After you have sweated, your skin is free of oil and the sweat has also evaporated or left.

Note: By-the-way, if you have oily skin, your hair dryness (your other question) can be solved by frequent but gentile brushing which spread the oil along the shafts of your hair.

On Wikipedia there is a great drawing which shows a hair follicle and sebaceous gland (oil gland).

Answer 2

Sweat contains a certain amount of urine which is acidic. (this is also why sweat is salty)

The acidity of the urine cuts through the fatty acids that make up the natural oils on your face.