When I pick out underwear to wear before a workout, it feels like choosing which pair of panties I’m willing to sacrifice. Which brave soldier will stand up to sweating and stretching, only to be unceremoniously discarded onto the pile of laundry after just an hour of use. I’m sorry, underwear!

But the sacrifice always felt like a necessary one. I was curious, however, whether wearing underwear to work out was, in fact, a non-negotiable. To Maria Sophocles, MD, an OB/GYN at Princeton Gynecology who deals with the gynecological concerns of athletes like ballerinas and the National Women’s Rowing Team, it is. But it’s really a matter of comfort.

“Underwear is a good barrier,” Dr. Sophocles says. “Some workout wear has seams that can chafe different parts of the body. So in general, I recommend you wear underwear.” More than that, however, Dr. Sophocles emphasized that, whether you go wear it or go commando, the most important thing when it comes to maintaining good vaginal health and working out is that you don’t let your lady bits stew in sweat any longer than they absolutely must.

“The longer you allow moisture to stay against the skin, you’re tempting fate,” Dr. Sophocles says. “You are allowing bacteria to grow or yeast to grow and odor to form.” (Same goes for soggy swimsuits, just FYI.)

Most people may not think of the vagina as, um, sweaty, but the labia majora have sweat glands. So when you exercise, you are producing sweat from your vagina. Dr. Sophocles did not give a specific amount of time it’s okay to wear wet bottoms, but she did say you should swap your underwear (or leggings if you go commando) before leaving the gym or studio. She recommends throwing any extra pair of undies in your purse for this purpose.

And choosing the right pair is important, too. Dr. Sophocles suggest opting for sweat-wicking ones to reduce the amount of moisture collecting around your vagina. Here are options in four different styles.

Moisture-Wicking Underwear for Working Out

Icebreaker Siren Bikini Underwear, $16.83-$35

This bikini cut wicks moisture through a fabric made from nylon and (itch-free!) merino wool.

Parade Sweat-Wicking Workout Thong — $13.00

The lining of this workout thong is made from organic cotton, so the pair will both wick sweat and let you breathe.

Lululemon UnderEase Mid-Rise Hipster Underwear 5 Pack — $74.00

A five-pack of Lululemon’s modal and lycra blend has got your workout covered for every weekday.

Girlfriend Collective Sport Brief — $18.00

This pair is moisture wicking and made from 80 percent recycled plastic bottles. Nice!

So whether you’re going commando or prefer panties, the same golden rule applies: Get that sweaty garment off as soon as possible!

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