Here’s Every Gross Thing Living Inside Your Gym Bag

Your gym bag is home to an endless list of bacteria, fungi and even faecal matter. Here’s what’s living in there, and how to get rid of it.


A trip to the gym can make you feel really good about yourself. You feel stretched out, you feel energised, you feel healthy… wait, did we say healthy? Scrub that one — until you’ve scrubbed your gym bag, at least.

Despite how neat and clean a person is in other aspects of their lives, most of us are total slobs when it comes to our gym bags. They sit under your desk at work, sweaty clothes balled up in a wet towel on top of crusty sneakers, silently brewing their own dank ecosystem of nastiness for what can be days at a time. The following look at what’s actually happening in there might make you reconsider how often you wash that filthy thing out.

The Bacteria
If you surveyed 10 billion bacteria about their ideal setting for a titanic orgy, the consensus would probably end up looking a lot like the inside of your gym bag. Bacteria need four things to reproduce: Time (say, 12 hours under your desk or in the trunk of your car); food (yum, clothes covered in dead skin cells!); moisture (lots of lovely sweat!); and warmth (say, the humid interior of a dark, enclosed space).

A recent study found that 60 percent of gym bags contained “significant” bacteria contamination. Among the myriad different kinds you might encounter are Coliform bacteria (which come in several varieties, including E. coli, and are generally a good indicator of the presence of other germs that feast on faecal matter — more on that later), Micrococcus luteus (which have been associated with everything from pneumonia to meningitis); Pseudomonas aeruginosa (which will cling to your swim clothes, and love to gift hosts with such conditions as hot tub rash and swimmer’s ear); Arcanobacterium haemolyticum (rashes, sore throats); and Corynebacterium (everything from bad smells to Diphtheria); but this is really just scratching the surface… something you’ll want to avoid doing to your skin with your fingernails after handling your bag.

The Fungus
Moulds and mildews are at their happiest in warm, damp places — say, for example, the crotch of your favourite running shorts. If you’ve ever left clothes in the washing machine for too long, you’ll be familiar with the musty smell of mildew, but it’s so much worse when it comes to your gym bag, because the chances are, you don’t just have your fungus in there — you have spores from half the people in the gym. Just as a sample, your bag could well be sprouting Aspergillus, a mould that grows on clothes and can cause respiratory problems. Or perhaps it’s covered with Cladosporium Herbarum, a common mould that can trigger allergic reactions and asthma attacks.

Then there’s the shower room. You might think you’re outsmarting the various stall floor germs by wearing flip-flops, but unless you’re carefully washing them and bagging them separately, the main thing you’re achieving is taking everyone’s filth with you in your bag. Filth like dermophytes, specialised fungi that utilise keratin to infect your skin, hair and nails, leading to conditions ranging from athlete’s foot to ringworm. Hope you don’t also keep your lunch in that bag.

The Poop
If the thought of bacteria and mould seems a little too nebulous, let’s be more direct. No one would voluntarily carry a bag of poop around — dog owners in search of a trash can excepted — and yet that’s exactly what you’re doing with your gym bag. A recent study from the University of Arizona found that there is faecal matter on 30 percent of gym bags, a result, most likely, of either being placed on the floor of a public bathroom, or people walking from the bathroom and across the changing room floor your bag is resting on.

It’s not just the outside of your bag, either. As with the flip-flops, unless your outdoor running shoes are sealed off from the rest of your stuff in there, they’re spreading all manner of crap — literally. Another study from the same university found Coliform bacteria — the ones we mentioned earlier that are generally to be found in poop — on 96 percent of shoes. Dogs, birds, rats — any animal that has pooped on the street has essentially now pooped in your bag.

The street isn’t the only place you’re picking up faecal matter. Swimming pools are notoriously full of it, which means your swimwear, now damply settled in your bag, is also covered in it. Even yoga mats are often contaminated with the stuff. It just goes to show, all that straining can’t be good for us.

Keeping it Clean
So what’s the solution, besides immediately killing your gym bag with fire? Firstly, don’t leave your dirty gym stuff in there. Empty it out the first chance you get and wash your clothes. Wipe the insides of your bag down with disinfecting wipes and leave it open — and empty — to air out and dry thoroughly overnight. If it’s already a stink-fest in there, scrub it out with hot water and soap (some people also recommend putting it in the washing machine with half a cup of white vinegar). And if all else fails, throw it in the trash and vow to be better to your next unlucky stench-sack.