Treadmill Vs. Outdoor Walking

Outdoor walking offers benefits that indoor treadmill walking doesn't, including the opportunity to combine exercise with your everyday chores and a more interesting experience if you want to observe scenery and people. From a physical fitness perspective, though, treadmill walking and outdoor walking can be equally valuable because treadmills can be very sophisticated.

Explanation

Most treadmill walking machines are powered by a motor. Consequently, many people assume that you burn more calories walking outdoors because it is more difficult, wrote "The Complete Guide to Walking" author Mark Fenton. However, Fenton reports that walkers exert most of their energy by lifting and putting down their legs and swinging their arms and legs back and forth. Consequently, you work "just about as hard" outdoor walking and treadmill walking and burn approximately the same amount of calories, wrote Fenton. Differences occur when there are surface irregularities. Outdoor walking surfaces are more apt to have bumps and cracks. These irregularities often compel walkers to exert "a little bit of extra muscular effort" and, thus, burn more calories, according to Fenton.

Weight-loss Stats

Speed and effort determine how much weight walkers lose. Walking a 13-minute mile, a pace of about 4.5 mph, burns 444 calories per hour if you weigh 185 lbs., 372 calories per hour if you weigh 155 lbs. and 300 calories per hour if you weigh 125 lbs., according to a 2004 "Harvard Heart Letter" study. The statistics reflect outdoor and indoor walking. Walking a 15-minute mile, a pace of about 4 mph, burns 400, 334 and 270 calories per hour if you weigh 185, 155 or 125 lbs., respectively. Walking a 17-minute mile, a pace of about 3.5 mph, burns 356, 298 and 240 calories per hour if you weigh 185, 155 or 125 lbs., respectively.

Inclines

Many treadmill walking machines offer adjustable inclines that allow walkers to give themselves a greater challenge, exercise more intensely and burn more calories. Outdoor walkers can find similar challenges by looking for hills or hiking in areas with rough terrain, but they're less likely to be able to switch back and forth from straight surfaces to inclines. Fenton suggests buying a treadmill that allows you to walk up a 10 percent or greater incline. Walking up a 10 percent incline indoors or outdoors increases the amount of calories you burn by 52 percent. Inclines of 6, 15 and 20 percent, which is considered a steep incline, increase your weight loss by 16, 67 and 70 percent, respectively, according to "The Complete Guide to Walking."

Considerations

Outdoor walking is one of the least expensive exercises. "Guide to Walking" author Mark Fenton recommends that novice walkers spend $50 to $75 for a good pair of walking shoes, either athletic shoes or light hiking shoes, but says no other special equipment is needed. Treadmill walking machines, however, can cost more than $2,000. Fenton recommends buying a treadmill with a calorie counter and heart-rate monitor if you intend to use it regularly. The price seems exorbitant, but Fenton reports that people on a six-month weight-loss program lost an average of six more pounds if they had a home treadmill.