How often should you wash your sports bra? Experts reveal the answer..and it's more often than you think

Picture the scenario: you've just completed a relatively low-key workout are changing out of your gym clothes.

Does your sports bra go in the laundry basket? If the answer is no, you'd not alone. 

According to a recent poll of 2,000 regular exercisers, just half of people wash their sports bras after a workout. 

In fact, a fifth said they wear the same one up to three times before washing it. And one in 10 said they re-wear up to six times.

But just how gross is this?

Bad news for laundry dodgers: failing to wash a sports bra and other underwear worn during exercise immediately afterwards could put you at risk of irritated skin and nasty infections, according to experts. 

Re-wearing your sweaty gym clothes can cause bacteria and fungus to grow in greater numbers on the skin, experts say

'If you're reusing them [gym clothes], not only will it probably like smell like sweat, but it's trapping bacteria and like, dirt and sebum and oils,' Dr Anthony Rossi, a professor of dermatology at Memorial Sloan Kettering in New York, told DailyMail.com.

Bacteria love water and warmth - and both get trapped under sweaty gym clothes, Dr Rossi explained. 

Warm sweat causes the bacteria, fungus and yeast on your skin to multiply, which can get into hair follicles and cause unsightly bumps or acne.

On top of the bacteria that lives naturally on your skin, there are lots of bugs that you might come into contact with at the gym, Rossi said.

A 2020 study from researchers at University Hospitals Cleveland Medical Center found evidence of two types of drug-resistant bacteria and flu virus on 25 percent of all the gym surfaces they analyzed. 

Those researchers identified one particularly frightening drug-resistant bacteria, called Methicillin-resistant Staphylococcus aureus (MRSA), which live on gym equipment for hours, days or weeks, according to the CDC.

Drug resistant bacteria can live on gym equipment for weeks, according to the CDC

MRSA, a drug resistant bacteria, under the microscope. Though skin infections with this bacteria are often treatable, if it gets into your blood stream, it can cause septic infection and death

If MRSA gets into a cut or scrape, you can develop large, red boils on your skin that fill with puss, according to Dr Mark Fisher, a plastic surgeon at Johns Hopkins.

Usually, these skin infections are treatable, Fisher said on a University Q&A. But in rare cases, if you don't seek help for the condition, it's possible for the bacteria to get into your blood stream, which can cause severe disease, according to the NIH. 

'If you spend time in locker rooms, schools, gyms or even prisons, be very careful to avoid cuts and scrapes, and if you get a skin injury in any of these environments, wash it thoroughly,' Dr Fisher said.  

Despite this gross reality, only 46 percent of people polled by UK firm Live Football Tickets reported that they worried about the presence of germs when considering whether to wash their undergarments after the gym. 

Instead, 55 percent said they just paid attention to its scent- and let their clothes be recycled until they were stinky. 

If for some reason, you're not able to get a full wash of your gym clothes, Rossi has some tips. 

If you're travelling, you can at least run your sweaty clothes under some hot water in the hotel, ring them out and then hang them to dry. He tells his patients that this can help, because 'it at least allows the water to evaporate,' which can at least partially stymie bacterial growth. 

Also, Rossi said some fabrics are more susceptible to harboring bacteria than others.

For example, natural materials like cotton might have a looser knit that allow for better air than synthetic fibers.