Measure your band size and then your bust size while placing the tape at the fullest part of your bust,” says Laporte. “Subtract the band size from your bust size to find the right cup size. Every inch equals one cup size up. For example: if the band size measures 34 inches and the bust size 37 inches, your cup size is a C cup (37-34 equals 3, which equals a C cup [0=AA, 1=A, 2=B, 3=C, and so on]). The bra size would be 34C.” The impact level describes the type of activity that the bra would be suited for,'' Ferriter says. “High-impact bras will be for your higher impact movement, like running, jumping, HIIT training, and plyometric work. Lower-impact will be best for activities like walking, jogging, strength training, and even walking around town.” Medium impact is between support levels and is great for activities like cycling, barre, and studio fitness classes. While it’s tempting to simply toss a sweaty bra into the washing machine after a killer workout, “I always recommend that you hand wash your bras in a mild detergent for lingerie. A three-to-five-minute soak in the sink should do,” Laporte recommends. But that's not all there is to it. Trust us, even if you're a long-serving member of the itty-bitty committee, don't be fooled into thinking your sports bra size doesn’t matter. Bowles K-A, Steele JR. Effects of strap cushions and strap orientation on comfort and sports bra performance. Medicine & Science in Sports & Exercise. 2013;45(6):1113-1119. doi:10.1249/mss.0b013e3182808a21

The band should fit snug, and the cups of the bra should lay smooth, with all breast tissue contained inside,” Laporte says. “When you are getting the proper support from your sports bra, the fullest part of your bust should be halfway between your shoulder and your elbow,” she adds. She and Ferriter both recommend choosing a bra that has adjustable straps or a band with a hook and eye closure for a customizable fit, especially for larger breasts. If you are looking for something for large breasts, there are several brands that make the best sports bras for large breasts.

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Bowles K, Steele JR. Effects of Strap Cushions and Strap Orientation on Comfort and Sports Bra Performance. Medicine & Science in Sports & Exercise, 45(6), 1113–1119. doi:10.1249/MSS.0b013e3182808a21 What Are Hoochie Daddy Shorts? Here’s Everything You Need To Know About This Season's Short Shorts: She adds that you should ensure the bra offers full cup coverage and separation without any gaping or pinching. Before shopping, try using a tailor’s measuring tape or a bra fitting professional like Laporte to help you find your band and bust size. Then follow product measuring charts, professional recommendations, and your comfort level for the best success.

In May 2023, the Center for Environmental Health (CEH) announced that, after testing, it found high levels of BPA in certain activewear pieces containing blends of polyester and spandex, including sports bras from Sweaty Betty, leggings from Nike, Athleta, Champion, Patagonia, and Kohl’s, shorts from Champion, Nike, and Adidas, and athletic shirts from Fabletics. We may recommend some of these products or similar items from these brands in this list, as these products have not been recalled and the science on transdermal absorption of BPA is still not settled. Made for high-impact moves, the molded cups separate and support to keep bounce at bay (which can be especially helpful for larger busts). Best of all, the band, straps, and edges are soft and body-smoothing, yet don’t dig in. The bonded seams lay flat to prevent chafing while en route. We love that the Drive 3 is available in a variety of colors that pop and follows traditional bra sizing so you can get the right fit. While this bra only comes in two colors, the patterned version is designed to hide sweat, even during a tough workout. With a strong band and compressive material, it’s ideal for low- to medium-impact activities. However, it may not have enough support for those with larger busts.Choose a bra with support features that will make it comfortable for the workout you’re doing. “High-impact bras are great for running, jumping, weight training, etc., whereas low-impact sports bras are good for activities such as yoga, and Pilates,” Amanda Barton says. She adds that the support level you need usually corresponds to your activity intensity. Bisphenol A (BPA) is a chemical found in some types of plastic. Research has shown that exposure to high levels of BPA can lead to obesity, hormonal imbalances, and uterine cancer, among other health complications. You can also machine-wash most bras unless the manufacturer states otherwise. “If you put your bras in the washing machine, use a lingerie mesh bag and always hook the bra before putting it in. Place it in a delicate cycle and only place lightweight delicates in the wash with them. Never put your bras in the dryer—the heat melts the delicate fibers and elastic,” she adds. All three support levels have specially designed materials and structures appropriate to their intended use. “High-impact sports bras are designed to meet the extra demands of any active lifestyle,” Laporte says. “They have stronger, more supportive materials than low-impact sports bras and have a different construction overall that makes them more supportive to guarantee less up and down movement of the breast.”