Is your tattoo changing the way you sweat?

Go to any CrossFit box, group run, or trendy downtown yoga spot and it’ll immediately become clear that the most popular fitness accessory isn’t some chic BPA-free water bottle or studio-specific tank—it’s fresh ink.

Tattoos have become a very visible part of the fitness world, from the recreational gym level to professional athletes. While tats used to be something you’d discreetly cover up for a black-tie wedding, they’re now considered more than just socially acceptable: they’re wellness world-approved.

But whether you already have a tattoo or are thinking of getting inked on your next Whole Foods run, you may want to consider this PSA. According to a new study published in Medicine & Science in Sports and Exercise, having a tattoo is probably changing the way you sweat.

What does this mean for the butterfly you got tattooed on your hip when you turned 18?

The small study looked at 10 healthy, tattooed men over the age of 21 to determine if there were any lasting side effects of having all that ink on your body. The scientists placed discs on tattooed skin and an un-tattooed part of the body before chemically inducing sweat (whoa) to compare the results. The result: Not only did the tattooed area sweat less than half as much as its counterpart, but it also contained twice as much sodium.

Although the researchers aren’t yet sure exactly what’s causing this change, they said it could be because the ink blocks the sweat glands or because the tattooed area creates an altered chemical environment, which could cause your body to steal sodium from nearby cells.

What does this mean for the butterfly you got tattooed on your hip when you turned 18? Not much. Maurie Luetkemeier, lead study author and professor of integrative physiology and health science at Alma College, tells The New York Times it’s unlikely that this would have any major effect on your LEFKit class sweat sesh since the body is intelligent enough to sort its own stuff out.

Unless you’ve got head-to-toe tattoos and very little visible un-inked skin, you should be good to go without any concerns. (So don’t worry, that little butterfly is not your new nemesis.)

Intrigued by the sweat talk? Read more about the relationship between your workout and sweating, and then learn how to DIY your own detoxifying sweat session.