Go outdoors. Grass, sand, dirt, and roads are never completely level, so they work out muscles more effectively than a treadmill does, says Michele Olson, Ph.D., a professor of exercise science at Auburn University at Montgomery, in Alabama. You also burn more calories when you contend with wind, which, Olson says, “increases resistance, as if you’re walking up a small hill.” Research suggests that being in nature also improves mood.
Get creative indoors. Walking downhill is essential for building strength in the quadriceps and shins, says Olson. (Most people get sore after hiking on hills not because of the climb but because their muscles aren’t used to the descent.) So if you must walk on a treadmill, dial up the incline. And turn around, so you’re walking backward for a few minutes.
Use a pedometer. A 2007 Stanford University study reported that keeping track of your steps increases physical activity by about 27 percent, which amounts to roughly an extra mile of walking each day. Public-health and transportation consultant Mark Fenton recommends the Omron Tri-Axis pedometer ($27, amazon.com), which tracks steps taken and time elapsed. You can also download the Moves mobile app ($3, iTunes and Android Market), which requires almost zero setup and converts a smartphone into a pedometer.