Here's Why You Should Never Re-Wear Your Workout Clothes Before Washing

Even the most organized people can have an off day that demands cutting corners. Maybe you wake up late, forget your lunch, and realize that you've got no clean exercise gear left for your trip to the gym. So, what do you do? You skip half of your morning routine, get takeout on your lunch break, and grab yesterday's already-worn gym outfit for a quick reprise. But it turns out that this last shortcut may be more trouble than it's worth.

When it comes to re-wearing dirty workout clothes, your first concern may be the stink. And you're right! When old sweat and skin oils build up in exercise gear — say, in the padding of that sports bra or jockstrap — they can cause lingering funkiness. This can be especially true with any moisture-wicking materials, which may continue to trap contaminants even after washing (via The Washington Post).

But while unpleasant odor may be bad enough — after all, you don't want to be the smelly kid in your spin class — it's unfortunately not the worst that can happen if you re-wear soiled workout clothes. General hygiene aside, donning your exercise gear more than once between washes can set you up for some persistent health and skin issues.

When you complete a workout, your outfit has probably absorbed a fair amount of sweat. But that sweat brings other impurities with it, such as skin oil and bacteria. So, if you leave on your exercise gear for hours or re-wear it for multiple days, you're exposing your skin to some less-than-fresh conditions.

When reintroduced to your skin from dirty clothes, trapped bacteria can proliferate, causing irritation, rashes, and sweaty acne breakouts. Bacteria can even cause infections in your follicles or any open cuts or scrapes. "Dirty, sweaty gym clothing is a breeding ground for pathogens such as bacteria and viruses, and their use can increase risks for superficial skin infections," dermatologist Deanne Mraz Robinson, M.D., tells The Healthy.

In some cases, this trinity of sweat, heat, and bacteria can also cause conditions like heat rash by clogging your sweat glands or intertrigo, a form of skin inflammation (via Runner's World). And for anyone with a vagina, there's another notorious consequence of bacterial imbalance: yeast infections. Re-wearing dirty exercise bottoms or underwear can be especially dangerous in the naturally damp and high-temperature conditions around the genitalia, triggering an unpleasant bout of bacterial vaginosis (via Health Shots).

All in all, the situation is pretty dire. So, the next time you're doing laundry, how can you make sure you're washing all the right workout clothes to keep your skin clean, dry, and protected?

In an ideal world, you should treat every piece of exercise gear to laundering between workouts. But if that's not feasible, here's how to prioritize washing your clothes — and which pieces to avoid re-wearing at all costs. First, ask yourself: how much did I sweat in this garment? If you were doing high-impact exercise or something extremely sweat-inducing like hot yoga, your clothes have probably soaked up more impurities than if you'd just taken a walk around the block. The sweatier your workout was, the more vital it is to wash your outfit pronto.

Your next question should be: was this item touching my bare skin? Workout clothing like sports bras, leggings, or tight-fitting shorts and tank tops often have a lot of skin contact, allowing them to thirstily soak up sweat, oils, and bacteria. As such, these can be highly unhygienic to wear a second time. If it was something loose and layered like a sweatshirt, you may have a little more leeway. "Re-wearing a running windbreaker is totally different than re-wearing your socks," dermatologist Elizabeth Nieman, M.D., tells Livestrong. "The clothing you wear closest to your body gets the most sweat into it and has the most contact with skin, so it's very important to wash after each use."

If you've considered both of these factors and still aren't sure whether an item can be safely re-worn, it's probably safest to consign it to the laundry. When in doubt, better to unnecessarily wash your workout clothes than risk exposing your skin to nasty contaminants and potential infection.