Exercise is Key to Keeping Weight Off

Ramp Up Your Workouts to Shed Pounds, Keep Them Off, Study Shows

By Kelley Colihan
WebMD
Reviewed by Louise Chang, MD

July 28, 2008 -- How much do you have to work out in order to lose weight and keep it off? The answer is hotly debated among people who study weight loss.

A new study says that obese and overweight women need to cut calories and exercise 275 minutes a week more than their baseline physical activity -- or at least 55 minutes a day, five days a week to lose weight and keep it off.

The research was led by John M. Jakicic, PhD, of the University of Pittsburgh, and colleagues.

They tracked 201 overweight and obese women over a two-year period; 170 women completed the study.

At the start, all of the participants were sedentary. They were randomly assigned to one of four groups based on how much and how intensely they exercised and how many calories they burned.

The participants were told to eat or drink no more than 1,200 to 1,500 calories a day. Researchers tracked them by talking to them on the phone and having face-to-face talks.

Participants were encouraged to spread the exercise out over five days during a week, done in at least 10-minute chunks. The women were given treadmills to use at home and taught to monitor their own heart rates.

At the end of the two-year study, women who had lost 10% or more of their initial body weight reported that they had done more physical activity compared with those who did not lose as much weight.

After six months, women in all four groups had lost an average of 8% to 10% of their initial body weight. But the hard part was keeping that weight off. Most of them regained the weight.

Nearly 25% of the participants managed to keep 10% or more of their original body weight off over the two years.

But, those women who exercised about 275 minutes a week more over their baseline activity levels were the biggest losers.

They also got the most support, completing the most telephone calls from researchers, and said they participated in more eating behaviors recommended for weight control than those who gained the weight back.

Those who lost and kept off the weight also increased their leisure time physical activity, doing things like taking the stairs and moving about more at home and work.

A couple of limitations the study authors note are that diet alone was not included as one of the options and that the participants themselves reported what physical activity they did and how well they did it.

The study authors conclude that a relatively high level of physical activity is needed to lose weight and keep it off.

These results are likely to add fuel to the debate over how much is needed to lose pounds and keep them from creeping back.

General recommendations are for 30 minutes a day, or 150 minutes a week, of moderately intense activity most days of the week. But the debate rages on over a magic formula for sustaining weight loss.

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Intense Exercise Curbs Metabolic Syndrome

Any Exercise Is Good, but to Really Make a Difference, Try Aerobic Interval Training

By Miranda Hitti
WebMD
Reviewed by Elizabeth Klodas, MD, FACC

July 7, 2008 -- Metabolic syndrome, which makes diabetes and heart disease more likely, may have met its match in exercise -- especially when it gets intense.

People with metabolic syndrome have at least three of the following traits:

• Large waist circumference

• Low levels of HDL ("good") cholesterol

• High levels of triglycerides (a type of blood fat)

• Elevated blood pressure

• Elevated glucose (blood sugar) levels after fasting

Research has already shown that moderate exercise can help curb those risk factors.

Now, a new study from Norway shows that aerobic interval training -- in which people push their heart rate almost to its limits briefly, followed by a more moderate pace, several times during a workout -- may be even better at reining in metabolic syndrome.

"Guidelines calling for 30 minutes of exercise of moderate intensity may be too general" for people with metabolic syndrome, researcher Arnt Erik Tjonna, MSc, of the Norwegian University of Science and Technology in Trondheim, Norway, says in an American Heart Association news release.

Intense Exercise

The new study included 32 adults with metabolic syndrome. They were assigned to one of three groups: aerobic interval training, continuous moderate exercise, or no exercise.

For four months, the patients in the exercise groups walked or ran "uphill" on a treadmill for about 40-50 minutes, three times a week, while wearing heart rate monitors.

After warming up, the patients in the interval training group walked or ran for four minutes at 90% of their maximum heart rate, slowed down to 70% of their maximum heart rate for three minutes, and then repeated that cycle several times.

The patients in the continuous moderate exercise group worked out steadily at 70% of their maximum heart rate throughout each session. Session duration was adjusted between the two groups to ensure similar calorie expenditures.

Harder Exercise, Bigger Improvement

As expected, metabolic syndrome didn't budge in the no-exercise group, but both exercise groups got healthier.

Although both exercise groups lost the same amount of weight, the interval training group showed more improvements in how their bodies handled blood sugar and responded to insulin, a hormone that controls blood sugar. Also, HDL ("good") cholesterol increased by about 25% in the interval training group, but not at all in the other groups.

Larger studies are needed to confirm the findings, but "high-intensity exercise training programs may yield more favorable results than programs with low to moderate intensities," Tjonna's team writes in the advance online edition of Circulation.

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