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.
A big caveat, however, is that if you’re going to wear your sweaty garb again, it’s important to hang it up to dry in between uses as that will limit the growth of bacteria, says Tierno. Drying alone can reduce up to 90 percent of the bacterial population that’s set up shop in your clothes, says Reynolds. Sill, that means 10 percent (or more) can remain, and because of how quickly bacteria can grow, “the higher baseline you start with, the quicker it can ramp up to really high populations that could be a health risk,” says Reynolds.
Here’s everything that could go wrong when you re-wear workout clothes.
Re-wearing dirty workout clothes isn’t 100 percent risk-free for everyone. Though most of the bacteria that resides on our skin is pretty harmless, certain types of germs, including staphylococcus bacteria (what causes Staph infections, including MRSA), can introduce more serious health consequences. To back up, staphylococcus typically isn’t a concern for the general population, says Reynolds. In fact, it’s commonly found on the skin of healthy folks, and most of the time, causes zero problems, or just relatively minor skin infections, per the Mayo Clinic. But some people, for various reasons, are prone to developing more serious Staph infections. And if you know that’s you (i.e. you have a history of Staph infections), “I would be ultra-vigilant about reducing those types of exposures like with reuse of clothing,” says Reynolds.
Also, if you are prone to inflammatory skin conditions, like acne or folliculitis (inflamed hair follicles), re-wearing the same gym clothes could increase your risk of an outbreak. That’s because these conditions often start with a pore getting clogged or obstructed with a particle, like skin cells, dirt, or debris, Jeremy Fenton, M.D., board-certified dermatologist, NYC-based medical director for Schweiger Dermatology Group, and clinical instructor at Mt. Sinai Hospital, tells SELF. When you re-wear sweaty clothes without washing them, the bacteria and particles of dirt that are clinging to your clothes can rub onto your skin and trigger the inflammatory response that causes acne and folliculitis.
There’s also the risk of yeast infections. “Naturally, we have yeast that lives on our skin and yeast really thrives in moist, warm, humid environments,” explains Dr. Fenton. “So if you wear clothing and sweat in it and that clothing sits wet for a period of time, more yeast is going to thrive on that clothing.” Then, if you put that clothing back on, especially on top of areas of the body that are more prone to growing yeast—like the groin, under the breasts, and other areas with skin folds—you are potentially introducing a higher level of yeast. These higher levels of yeast can lead to skin irritation, and various yeast-based conditions, like tinea versicolor (a harmless infection that causes skin discoloration), and pityrosporum folliculitis (also known as fungal acne), explains Dr. Fenton.
Another area for concern is if you have a bruise, cut, or break in the skin. Any type of opening provides a “major entry point into the bloodstream,” says Reynolds, and harmful bacteria can slip inside. Any break in the skin should be treated with antiseptic and bandaged well, says Tierno. If it’s not bandaged well, you definitely shouldn’t put dirty clothes on top of it.
Also, if something smells like B.O. after you worked out in it once, that likely is going to still smell like B.O. until you wash it. So definitely don’t re-wear something that smells.
Lastly, please don’t borrow or lend sweaty clothes. “If you share your clothes, that’s a whole other ball game,” says Tierno, as swapping clothes could also mean swapping harmful bacteria. Say you recently got over the flu or a stomach bug, for example. Those bacteria could still be present on your skin, and then transfer onto your clothes as you exercise. Then, by sharing those sweaty clothes with someone else, you could be exposing them to the same illness. “I recommend not sharing anything,” says Tierno.
These are the items that should always be washed after you work out in them.
While most clothing items are probably OK to re-wear (given the caveats noted above), anything directly touching the groin area—including underwear and any pants worn commando—should definitely be washed after every use, says Dr. Fenton. There’s a higher concentration of bacteria in your groin area to begin with, and it’s also a much more welcoming environment to bacteria and yeast, thanks to the warm, moist conditions and the fact that this area produces certain oils that bacteria like to feed on, he explains. On top of that, there’s more friction in that area when you’re moving, which increases the risk of depositing pathogens deeper into the skin.
Another reason to always wash your undergarments: The potential that microscopic fecal germs from your groin area could make their way to your mouth (say, you handle a pair of fecal-flecked pants and then touch your lips). Though the likelihood of this actually happening is pretty low, especially if you’re good about hand-washing and basic hygiene, there still is some risk, says Reynolds. For that reason, stick to washing your skivvies (and any pants you wear commando) after each use.
Socks are another item that should always be washed in between wears, adds Dr. Fenton. Why? If they touch the ground at the gym (for instance, you walk without shoes from the indoor cycling studio to the locker room), they could pick up fungal infections that could then get transferred to your feet the next time you re-wear ‘em.
Some final thoughts before re-wearing your workout clothes:
OK, so let’s say you’ve read all the warnings so far and are still feeling pretty good about your decision to re-wear that sports bra before washing it. Bold move—but possibly not a bad or gross one! Here are a few final questions to ask yourself:
Is this totally dry? Even if you hung it up after the last use, it may not be totally dry depending on where you live. Or, even if it’s dry now, it may have been damp for a long time. In high-humidity environments, like parts of Florida or Texas, for example, clothes will take much longer to dry than in arid places, like Colorado or Arizona, for instance. Remember, more moisture equals more bacteria, so if you live in a steamy place, you should probably wash your clothes more often.
What’s it made of? The type of material your clothing is made from also matters. If you have a material that doesn’t dry out within a few hours, “then you’re potentially incubating a lot of bacteria that could cause a problem,” says Reynolds. Clothes made with wicking, breathable material will be lower risk, she adds.
Did you sweat a lot in this? Also, consider how much you typically sweat. If you perspired profusely in this item of clothing, it’s a good idea to wash versus re-wear.
Seriously though, does it smell? Or did it smell at one time? You can also use your nose to make the call. “Once you can smell bacteria, you’ve got a lot of bacteria there,” says Reynolds, explaining that it takes a large population of bacteria before your nose will pick up on it. She suggests washing your clothes before they start smelling. So if you notice an odor after three re-uses, for example, you should probably start washing your garb after just two wears.
Are you maybe going to put your skin or health at risk by re-wearing this? If you have any health issues that impact your immune system, an open wound, or are typically prone to yeast, acne, or other bacterial skin infections, it’s best to wash your clothes after every use to avoid triggering or exacerbating health issues. If you’re unsure what’s safe for you, always talk with your doctor first.
In weighing the benefits of working out with the potential health risks of re-wearing dirty clothes, “if you’re a healthy person with a normal immune system, I would rather you re-wear your workout clothes and get a workout in than not work out at all because you don’t have any clean clothes,” says Dr. Fenton.
Just keep in mind all the tips listed above—let your sweaty clothes fully dry before you wear them again; re-wear them no more than two or three times before laundering; wash underwear and socks between every single use, etc.—and you won’t have much to fret over.
If you, like me, decide you’re going to re-wear your workout clothes occasionally, you should take off your sweaty clothes as soon as possible after your workout and hang them up in a dry place (not in the bathroom if it gets steamy whenever you shower) so they dry quickly, says Dr. Fenton. This will prevent the growth of bacteria and yeast.
To allow your clothes to dry more thoroughly before you re-wear them, you could alternate between two sets, letting one dry for an entire day or two while you wear the other, and vice versa, suggests Reynolds. Another option for combating bacteria: Spritz your clothes with a disinfecting or sanitizing spray that’s safe for fabrics and then hang them up to dry, suggests Reynolds. Or, if your clothing can go in the dryer, you could throw it in on a high heat cycle to further kill off bacteria, says Reynolds. “That would absolutely help,” she says.
With all of this in mind, I’ll happily continue with my habits, which turns out, aren’t so gross after all.