Wash or re-wear? As a minimalist millennial who loves working out, but hates buying new clothes and doing laundry, I frequently ask myself this question.
You see, I like to exercise most days of the week. But I own just a handful of sports bras, three pairs of shorts, and three pairs of leggings, and I typically do laundry only when necessary. Hence the conundrum I often face as I peel off my sweaty garb. Hamper or hanger?
More often than not, I go for option B: re-wear. I know it sounds gross, but I haven’t noticed any weird or bad side effects—health-wise, or otherwise—from this habit. That said, I know enough about science to understand that just because I haven’t observed anything sketchy doesn’t necessarily mean something sketchy isn’t going on.
So, to better inform my multiple-times-a-week decision, I asked two germ experts and a dermatologist for their take. Here’s what they said about the science of sweat, the health risks of re-wearing the same workout clothes, and the various factors that determine whether one should wash or re-wear.
Let’s talk about sweat.
You have bacteria coating all of the surfaces of your body, Philip M. Tierno, Jr., Ph.D., professor of microbiology and pathology at NYU School of Medicine Langone Health and author of The Secret Life of Germs, tells SELF. That may sound off-putting, but this plethora of bacteria, known as your natural flora, is totally normal and helps fight off outside, potentially harmful bacteria.
When your body temperature starts to rise (which happens when you exercise), your sweat glands release sweat onto the skin so that it can evaporate and cool you down. But first, the sweat mixes with the bacteria that naturally lives atop the skin, and because bacteria feed on moisture (among other things), this causes the bacteria to multiply, Kelly Reynolds, Ph.D., professor and chair of community, environment, and policy at the University of Arizona’s Zuckerman College of Public Health, tells SELF.
Some of this naturally occurring bacteria—not all of it, but some—produces an odor as it grows, explains Reynolds, which is why we typically associate sweat with body odor. Because these bacteria, for the most part, make up your natural microbiome, they don’t really pose a health risk when they multiply. “Most often, it's just kind of a nuisance, because the odor's not that pleasant,” says Reynolds. When we’re working out, these bacteria, and any resulting odor, can be transferred to our clothes.
The short answer: It’s kinda gross but not a huge health hazard for most people.
As for whether or not it’s OK to re-wear sweaty clothes, “the perfect public health answer would be to say, ‘Wash your clothes in between every use,’ but that's really not practical, and it's probably not necessary for most people,” says Reynolds. There are a lot of valid reasons why you shouldn’t re-wear workout clothes, and there are even some cases where you definitely shouldn’t, but for most healthy people, there aren’t any major health risks from re-exposing ourselves to bacteria that originated from our own bodies. So sweating in the same clothes twice before washing them is probably OK in most cases. “Even three [times], you’re not really pushing the envelope,” says Tierno.
