Tattoos found to increase heat stroke risk, but only if they're big

Getting a tattoo may increase your risk of suffering a heat stroke or other heat-related injury, according to a new study, but only if they're big. The issue is related to the skin's sweat glands and the damage they suffer when someone gets a tattoo, according to what is called a milestone study on the topic from the American Physiological Society. Sweating, of course, is an important part of regulating one's body temperature.

Tattooing is the process of implanting ink deeply enough into one's skin to make it permanent. Though this was traditionally done using thorns or sharpened sticks, modern tattooing involves using machines that rapidly jab the skin with sharp needles. The researchers point out that modern tattooing machines can apply up to 3,000 tiny skin punctures every minute, potentially damaging the sweat glands.

This process, according to the new study, can cause damage to sweat glands that may reduce one's ability to sweat in that part of their body. Though this may not be too big of a deal for someone who has a single small tattoo, the researchers note that people who have large tattoos may be at greater risk of suffering from a heat-related injury like heat stroke due to their body's impaired ability to regulate its temperature through sweating.

The researchers behind the study explain:

The primary new finding in the current study is that peripheral [hair follicle-containing] skin of the arm containing tattoos has reduced sweat rates, and thus potential heat loss capacity, during [whole-body heating] compared to adjacent skin without tattoos. These data indicate that the collateral effects of the tattooing process negatively impact eccrine sweat gland function and could be considered a potential long-term complication or side effect of this cosmetic procedure.

The findings were based on an experiment that involved exposing participants to heat and measuring the sweat produced on tattooed and non-tattooed skin. Though both sections of skin began sweating at the same time, the tattooed skin produced less sweat overall, hinting that sweat gland damage is behind the change.