So, back to the gym scenario. If you go to the gym with the intention of doing a high-intensity workout, but you don't have a bra, you can still find a way to get active, Dr. Moore says. "The priority is working out," she says. Your best bet is to just modify your routine and do something low key, like walking on the treadmill for 30 minutes , doing some gentle stretches , or lifting weights (yes, it's safe to lift without a bra), she says. And then when you get home, you can do some research and buy yourself an extra sports bra to have handy.