A small study suggests that having tattoos may affect how much you sweat, and could have health implications.
The study, led by Alma College in Michigan, involved just 10 healthy men aged around 21. Each had a tattoo on one side of their upper body (such as an arm), but not the other.
The researchers chemically stimulated the sweat glands, using pilocarpine nitrate, which initiates sweating. Small discs were then used to absorb the sweat that was produced.
After 20 minutes, the researchers found that the tattooed skin generated about half the amount of sweat as the non-tattooed skin. It also had a different composition, containing about twice as much sodium as the non-tattooed side. The findings, published in Medicine and Science in Sports and Exercise, were the same if the tattoos were young or old.
“To our knowledge, this is the first study of its kind to document alterations in sweating function associated with tattooing,” said lead author Maurie Luetkemeier in a statement. “However, we are somewhat cautious about our results. The process we used for stimulating sweat glands differs from the normal process, which involves cooling yourself following a rise in body temperature.”
They noted, though, that this study could provide a proof of concept for other studies. Heavily tattooed people may be more at risk of heat-related injuries, as their bodies are not able to expel heat as quickly.
“There is a maximum sweat rate that can be obtained,” Dr Angela Smith from Thomas Jefferson University in Pennsylvania, who was not involved in the study, told Healthline. “If you’re a marathon runner in the heat, a firefighter, or a soldier in a very hot climate you may already be sweating at your absolute maximum. So if you’re already at your maximum and now you lose your ability of a certain portion of your skin to sweat, all of a sudden you have a lower maximum than you did before... so now you could be at greater risk than if you didn’t have a tattoo.”
As mentioned, this was an extremely small study, so it’s certainly too early to jump to conclusions. Hopefully, further studies will illuminate whether this is something to be concerned about or not.