It has been hot and humid in Southern California! This weather is not making my daily run easier, but nevertheless I push through the heat, the hard to breath air and the excessive sweating stoically. Have you ever wondered why we sweat and what sweating does to our skin? There are a couple of misconceptions about the unglamorous act of sweating during exercising and how this affects our skin health.
Why do we sweat?
Science Spiel™: The thermoregulatory center in the hypothalamus (1) controls body temperature by regulating eccrine sweat output and blood flow to the skin. Both skin blood flow and product of sweat increased enormously in hot conditions and while exercising. Sweating increases in proportion with the intensity of thermal challenge: the hotter it is, the more we sweat! Sweating is the most powerful thermoregulator in the human body as evaporation of sweat provides the largest potential for heat loss maintaining heat balance and a stable internal temperature.
Beauty Spiel™: sweating allows water evaporation that cools the body down.
(1) Hypothalamus also respond to hormones, endogenous pyrogens (fever producing molecules) and emotions. That is the reason why we sweat when we see our special one or under stressful conditions.
How is sweat produced?
Science Spiel™: Sweat production results from the integration of afferent neural information from peripheral and central thermoreceptors, leading to an increase in skin sympathetic nerve activity. At the neuroglandular junction, binding of acetylcholine to the muscarinic receptors stimulates the secretion of a primary fluid by the eccrine glands. This fluid subsequently travels through a duct where ions are reabsorbed, resulting in hypotonic (lower concentration of electrolytes in comparison to sweat glands cells) sweat being released to the skin surface.
Beauty Spiel™: increase in temperature is sensed by our nervous system which activates the production of sweat. Sweat is mainly water, minerals (sodium, potassium, magnesium and calcium), lactate and urea.
Interestingly, sweat composition changes between individuals as depends on eating and drinking habits and external conditions such as air humidity and time of exposure to the stimuli (why and for how long we are sweating). Sweat may also help to get rid of toxins (*) and waste products, which is the reason why our ancestors love sweat lodge as a purifying experience.
(*) the most important detox function in our body are performed by liver, kidney and guts. Sweating may help but is not the driving force behind toxin removal.
Does sweat make me breakout?
Science Spiel™: Sweating is a natural process. As it is produced, sweat is sterile and odorless (**) with a composition similar to plasma and therefore our skin is cool with it. Sweat by itself does not cause breakouts. Most of the time breakouts are related to exercising with unclean skin (no make at the gym please!). The dirt or makeup left on our skin can clog pores resulting in pimples. Post-exercise body (chest and back) and forehead breakouts are mostly linked to an increase secretion of oil due to the friction between the skin and workout gear (a condition known as acne mechanica). Rarely, people can develop exercise-induced urticaria, in which you can break out in hives due to an allergic reaction to your own sweat.
Beauty Spiel™: sweat does not produce breakouts.
To avoid breakouts, make sure your skin is clean before and after exercising (I use alcohol-free gentle facial wipes). As I exercise 7 days per week (try at least) I like to exfoliate on a regular basis to remove cell debri and other impurities … I do not use physical exfoliants (do not like them at all!). I prefer to use cleansers with glycolic acid alone or in combination with phytic acid and I always always always moisturize body and face after running. I use breathable gear to minimize friction while running (this made a huge difference in my performance and look :)). If your have acne-prone skin these are key steps to prevent breakouts while enjoying exercising.
(**) Bacteria near the apocrine glands (armpits and groin which produce 7 times more sweat than eccrine glands) are responsible for breaking down the seat and produce the nasty distinct odor.
When sweating is too much for no reason - This is a condition called hyperhidrosis and may affect everyday activities. Diabetes, menopause, hyperthyroidism and tumors may increase sweating too. There are several in-office treatments for excessive sweat like neurotoxins and Miradry (non-sponsored).