In a world filled with adorable athletic gear, gym-friendly underwear gets surprisingly little attention. There are thousands of reviews on Amazon pointing you toward the best sports bras 鈥 but how do you pick the right knickers for your morning spin class or lunchtime Pilates sesh? And, heck, do you even need 鈥檈m? Surely there鈥檚 enough judgment at the gym without adding visible panty lines to the mix.

As it turns out, doctors have their own criteria for determining the best underwear for your workout 鈥 and you might want to listen up. We checked in with the experts to learn how your exercise habits can affect your health *down there.*

woman doing yoga

Exercise and vaginal health

Dr. Angela Jones, an OBGYN and Astroglide鈥檚 resident sexual health advisor, points out that the sweat and heat generated by your workout can set you up for a slew of unpleasant symptoms. 鈥淭he key thing to keep in mind regarding vaginitis [inflammation of the vagina, including bacterial vaginosis, yeast infections, and trichomoniasis] is that warm plus moist is a direct setup for vaginitis,鈥 she says. 鈥淭his is what all women try to avoid.鈥

That鈥檚 because yeast and bacteria thrive in a warm, moist environment, explains Dr. Alyssa Dweck, a New York-based OBGYN who works with urinary, bladder and vaginal health brand AZO. (We apologize for repeating everyone鈥檚 least favorite m-word 鈥 it won鈥檛 happen again.)

Both docs advise getting out of your exercise gear ASAP after a workout. (This rule also applies to swimsuits, so remember to bring a spare if you鈥檙e hanging at the beach this summer.)

Picking the right pair

Dr. Dweck and Dr. Jones both suggest picking breathable, lightweight underwear for the gym. 鈥淐hoose underwear with a cotton crotch,鈥 says Dr. Dweck. 鈥淐otton is absorbent and allows the area to breathe.鈥 Less absorbent materials like nylon, lycra, silk, and lace are best avoided, according to Dr. Jones.

But if breathability is the goal, why not just go commando? 鈥淟ess is not always more,鈥 says Dr. Jones. 鈥淚f nothing else, wearing underwear may serve as an extra barrier between your vulva and whatever equipment you happen to be working with.鈥 There鈥檚 an exception to this rule, however: 鈥淲orkout clothes have completely evolved,鈥 Dr. Jones acknowledges. 鈥淵ou may not even have to wear panties, as a lot of them either have built-in wicking material in the crotch or are made of materials that are highly absorbent.鈥

One final note: if nothing else, definitely skip the Valentine鈥檚 Day lingerie. 鈥淭hongs are not only uncomfortable, but can be irritating during a workout,鈥 says Dr. Jones. 鈥淎nd [they] may serve as a conduit of spreading bacteria from your 鈥榟ind parts鈥 to your vagina.鈥 That鈥檚 a hard pass from us.

What could go wrong?

1. Bacterial Vaginosis (BV): Women鈥檚 health expert Dr. Roshini Raj works with Keep Her Awesome, a resource for understanding BV and other vaginal infections. Raj points out that BV, which develops when you have an imbalance of good and bad bacteria, is the most common gynecologic infection among patients of childbearing age (14鈥49, give or take). In the US alone, 21 million people with vaginas are afflicted annually; one in three will have at least one occurrence of BV. Since it鈥檚 not an STI, you can get it even if you鈥檙e not getting it on. It can, however, be passed to partners with vaginas.

To limit your risk of developing BV, Raj also votes for cotton undies during exercise. 鈥淐otton is a comfortable, breathable material that will help limit excess moisture and avoid trapping heat during exercise 鈥 both of which create the perfect environment for bacterial growth.鈥 And you鈥檒l want to slip into a fresh pair before you leave the gym.

鈥淏V is not a matter of poor hygiene,鈥 says Dr. Raj. 鈥淏ut it鈥檚 important to keep in mind best hygiene practices, especially after exercise, to help avoid a vaginal infection.鈥 That means showering right away 鈥 or at least changing out of that sweaty workout gear.

When you do hit the showers, remember that your fave Bath & Body Works products don鈥檛 belong *everywhere*: Dr. Raj advises that scented soaps, like douching, can change the pH level of your vagina. 鈥淧lain water usually suffices to clean your vulva,鈥 she says, 鈥淏ut if you want to use a soap, make sure it is gentle and unscented.鈥

2. Urinary Tract Infection (UTI): 鈥淭here are no good data points to show that clothing can cause a UTI,鈥 says Dr. Dana Rice, a urologist and creator of the UTI Tracker app. 鈥淭here is not a specific fabric type that is better or worse.鈥 But Rice points out that those sweaty leggings can be a source of bacteria when they鈥檙e damp, or if they haven鈥檛 been washed properly. 鈥淔or my patients, I encourage clean undergarments and regular washing of all tight-fitting pants.鈥

And there鈥檚 another important step you should take at the gym to prevent UTIs: 鈥淗ydration, both during and after working out, is key to preventing bladder irritation,鈥 says Dr. Rice. She explains that dehydration can alter the pH of your urine and irritate the lining of your bladder. 鈥淢any people have cystitis-like symptoms if they are dehydrated,鈥 she says.

If you鈥檙e worried about your bladder keeping you up all night, Dr. Rice has a pro tip: 鈥淚 encourage patients to drink enough water in the morning to keep their urine light yellow or better by lunchtime.鈥 By the time the afternoon rolls around, you can sip a La Croix as needed, or snack on your fave hydrating foods.

Speaking of bladder issues鈥

Attention, new moms: We see you. There are a lot of complicated feels around exercise post-baby. You might be keen to hit the gym to boost your postpartum mental health or just to get a moment to yourself. Or maybe separation anxiety is too real and you鈥檙e hunting for baby-friendly mama workouts you can do from home.

Or 鈥 real talk 鈥 maybe there鈥檚 a little voice in your head wondering if underwear is *enough* to get you through that gym sesh. According to a representative from Poise, one in four women surveyed was hesitant to participate in workout classes, from yoga to Zumba, because of bladder leaks.

Their solution? Wear whatever underwear you like 鈥 along with a bladder support device, which you insert like a tampon. Also called an 鈥渋nternal vaginal device,鈥 products like Poise鈥檚 Impressa basically help keep your urethra closed when there鈥檚 extra pressure on your bladder, like when you鈥檙e exercising.

Do you have a fave pair of gym-friendly undies? Tell us where to get 鈥檈m @BritandCo!

(Photo via Getty)