A subtle stretch you can do anytime you're standing will help keep your calves limber and feet pain-free. "Most women who wear high heels will have tightening of the two calf muscles that join the Achilles tendon in the back of the heel," says Jaleh Hoorfar, DPM, a podiatric surgeon at New York–Presbyterian Hospital. That tendon can actually shorten over time, leading to heel pain and difficulty wearing flats. Hoorfar suggests this simple exercise to stretch your Achilles, increase circulation, and improve posture. While standing, shift your weight to your left foot and bend your right knee slightly. Lean back on your straight left leg while simultaneously digging your heel into the ground and pulling your left toes toward your shin. Hold for a few seconds, then return to a normal standing position. Do ten repetitions and then switch legs. Hoorfar recommends continuing the stretch, which will also help prevent varicose veins, for as long as you're standing. And you can do the stretch barefoot, in gym shoes, even in pumps.