Cassandra Forsythe, Ph.D., R.D., is an exercise physiologist and author of The New Rules Of Lifting For Women.
You should also take a good look at your sneakers. If they’re over a year old and looking worn (you can tell because the soles will look thin), it’s probably time to shop for a new pair.
The surface you’re working out on could also be an issue. Most wood floors should be okay, but if you’re in a basement on a hard concrete floor, get a workout mat—they’re thicker than a yoga mat—to add some cushioning. (Torch fat, get fit, and look and feel great with Women’s Health’s All in 18 DVD!)
You could also have the start of plantar fasciitis, which is inflammation of the muscle in the bottom of your foot. The most common sign is a sharp pain in your heel right when you get up in the morning. If so, be sure to always stretch your calves before and after exercising. Two good calf stretches: 1) Put the ball of your foot up against a wall, with your heel on the floor, and lean into the stretch, and 2) Do a down dog yoga stretch while gently raising and lowering your heels one at a time. If that doesn’t help and the pain continues, see your doctor for treatment.