In a small study, researchers say tattoos may change the way we sweat. This could have implications for athletes who have a lot of tattoos.

The tattoo on your body may be much more than a decorative statement.

It could be changing the way you sweat.

That was the finding from a small study at Alma College that examined changes in sweating function in tattooed areas of the body.

The researchers were led by Maurie Luetkemeier, PhD, a professor of integrative physiology and health science at Alma College in Michigan.

The researchers recruited 10 young men with tattoos on one side of their upper body but not on the other.

The researchers then used chemical patches containing a substance that induces sweating to stimulate the sweating process on both the tattooed and non-tattooed skin.

“This study is the first study of its kind to look at tattoos and sweating function. As such, we need to be cautious with interpretations, but we demonstrated that sweat production was about half in tattooed skin compared to non-tattooed skin. That may be very significant,” Luetkemeier told Healthline.

Luetkemeier has taught skin physiology, as well as the location and function of the skin glands, for years.

“I realized that the sweat glands were at the same approximate depth as the deposition of ink for a tattoo. It got me wondering if the tattooing process interfered with sweat function,” he said.

Luetkemeier said further study is needed to determine the potential ramifications of the findings, and to see if the same results would occur after exercise.

“In our study we used a chemical stimulant to stimulate the sweat glands. We did not heat anybody up nor did we have the subject perform any physical activity,” he explained. “Future studies need to be conducted to look at the risk of overheating when individuals are actually getting hot due to high environmental temperatures or heavy physical exercise.”

Sweating is the primary mechanism the body uses to cool itself, particularly in high temperatures.

As such, Leutkemeier’s work and follow-up studies could be of significant interest to athletes with tattoos who train in the sun and are at risk of overheating.

Others who may also be impacted include firefighters and soldiers.

“Military personnel have a high incidence of tattoos and are often exercising vigorously with heavy equipment in a hot environment,” Luetkemeier said.

Dr. Angela D. Smith, a past president of the American College of Sports Medicine and a clinical professor of orthopedic surgery and pediatrics at Thomas Jefferson University in Pennsylvania, said if the results of the study were also replicated following exercise, the consequences could be significant.

“This could well be a problem. There is a maximum sweat rate that can be obtained,” she 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.”

This could potentially not only pose problems for overall health but also in sports performance.

“The endurance athlete is already exercising at maximal capacity and that maximal capacity usually is going to include that they’re sweating at their maximal rate so if they now reduce their ability to produce sweat, say by tattooing 10 percent of their body, they can no longer achieve their same maximum,” Smith said.

Leutkemeier suggested that it’s unlikely individuals with limited amounts of tattooed skin performing moderate physical activity will be at risk of any negative consequences.

But the case may be different for heavily tattooed people who engage in vigorous physical activity in high heat, especially given the role sweat plays in preventing heat illness.

“Sweat rate is really critical to controlling the body temperature. The exercising body produces heat, the muscles are producing heat as they work and, exercise alone increases blood flow to the skin to help dissipate that heat through sweat,” Smith said.

Even elite athletes can succumb to heat illness and the consequences are significant.

“Heat illness causes muscle death. It causes kidney injury. It causes brain injury. It probably causes injures in other areas of the body we just don’t know about,” Smith said.

As for whether those with tattoos are more at risk of such heat illness remains to be seen.

“One would think that the risk would be in proportion to surface area covered,” Ollie Jay, PhD, a professor of thermoregulatory physiology at the University of Sydney, told Healthline.

“It is certainly very conceivable that tattoos impair local sweating responses, but the overall impact will be determined by the proportion of surface area covered by tattoos,” he added. “We also do not know if one has compensatory sweating in non-tattooed areas to account for the lower sweating over tattooed skin.”

So should those with tattoos be concerned? Maybe not.

Leutkemeier said his team has further investigations planned that will determine if the same result can be applied to exercise.

But Smith said the work has already raised some important questions.

“It’s one of those things where you think why didn’t anybody think of this before? Even though it’s a small group, a small sample size, it’s enough difference that we have to wake up and take a look at this,” she said.