March 3, 2004 -- If weight loss is your goal, a 15-minute walk might not be enough, one study shows.
"Fifteen minutes is good for your heart and your psyche, but not if you're not going lose weight," researcher Michael Costanza, PhD, a biostatistician at the University of Geneva in Switzerland, tells WebMD.
His paper appears in the current issue of the American Journal of Public Health.
Some researchers suggest that people could battle obesity by cutting 100 calories out of their diets -- or by burning an extra 100 calories through 15-minutes a day of a moderate or brisk walking, he says.
His study provides "a more realistic look" at the calorie burn from these recommendations. People have to walk a whole lot farther to walk off those extra pounds, Costanza tells WebMD.
In his study, Costanza uses five years of lifestyle surveys completed by 6,010 Swiss adults aged 35 to 74 years old. He then projected the calories burned by following a daily physical activity recommendation that involved walking. The participants walking program involved 15 or 30 minutes of daily walking done at a pace that was either slow, moderate, brisk or athletic-brisk -- the pace followed determine what the metabolic rate was and how many calories would be burned.
If the population as a whole followed the recommendation for physical activity his findings showed that:
- The average adult who walked 15 minutes per day at a slow pace would burn only an additional 9 calories per day.
- The average adult who walked 30 minutes a day at a slow pace would burn only an addition 25 calories per day.
Assuming that the population as a whole participated in harder levels of the physical activity, the following results would be expected:
- Walking moderately for 15 minutes per day burned 36 calories per day, where as moderate walking for 30 minutes burned only 85 calories per day.
- Walking briskly resulted in an increase in the calories burned. Fifteen minutes of a brisk walk per day resulted in 60 calories burned, whereas 30 minutes a day of a brisk walk resulted in 129 calories burned.
"If your goal is to burn 100 calories a day, 15 minutes just won't do it," says Costanza. "There's very, very little calorie burn in a slow walk. Walking briskly for longer periods will provide a fairly substantial boost in calorie burn. Then you will lose weight."
That's not true, says Madelyn Fernstrom, PhD, director of the Weight Management Center at the University of Pittsburgh Medical Center.
"You can lose 10 pounds with a 15- or 20-minute slow walk -- if you do it daily -- and even if you didn't cut back on calories," Fernstrom tells WebMD. "That 100 calories you burn will give you that 10-pound weight loss in a year's time."
What gets people into trouble is eating an extra 150 calories to compensate for all that activity, she explains. People waste their weight-loss efforts.
Fernstrom dislikes public health messages that "overwhelm" people -- messages about walking 10,000 steps, or for 45 minutes or an hour every day -- for weight loss. "People end up think nothing is good enough," she says.
She advises setting realistic goals: Start with a half-mile, 30-minute walk; then do a mile in 15 minutes; then two miles in 30 minutes. "The idea is, can you get more activity into the time you have," says Fernstrom.
For faster weight loss, cutting back on calories will also help -- "but exercise allows you to barter for a little more food," she explains. "Say you're cutting back 500 calories a day to lose 1 pound a week. If you get some exercise every day, you only have to cut out 350 calories. And let me tell you, 150 calories are really precious when you're trying to lose weight."
"Sure, you can lose weight by cutting back on eating, without the physical activity component," Fernstrom says. "There are a lot of books out there that tell you how to do it. But weight loss is much easier with physical activity."