From Our 2007 Archives

Moderate Exercise Cuts Risk of Metabolic Syndrome

By Kathleen Doheny
HealthDay Reporter

MONDAY, Dec. 17 (HealthDay News) -- A brisk 30-minute walk most days of the week is enough to undo metabolic syndrome, a health condition that can lead to heart disease, diabetes and stroke, a new study suggests.

"What we found was a modest amount of moderate intensity exercise was very effective in improving metabolic syndrome risk," said study author Johanna L. Johnson, a clinical researcher at Duke University Medical Center's department of medicine.

At the start of the study, 41 percent of the 171 participants had metabolic syndrome; at the end, just 27 percent did. The study was published in the Dec. 15 issue of the American Journal of Cardiology.

About one-quarter of all U.S. adults have metabolic syndrome, a collection of risk factors that can eventually set you up for more serious health problems. While some experts debate the validity of considering metabolic syndrome a disease unto itself, the risk factors are potentially dangerous. They include a large waist circumference; high blood pressure; high levels of triglycerides; low levels of good (HDL) cholesterol; and high blood sugar. If you have three or more of the five risk factors, you have metabolic syndrome.

Johnson and her colleagues looked at the effects of different amounts and intensities of exercise.

The researchers assigned the 171 men and women to one of four groups. One was a control group, whose members continued to be sedentary. The other three groups included:

  • A low amount/moderate intensity group. They did brisk walking three to five days a week, aiming for about 11 miles, and typically putting in about three hours a week.
  • A low amount/vigorous intensity group. They did the same 11 or so miles but at a jogging pace, so they ended up getting about two hours of exercise a week.
  • A high amount/vigorous intensity group. They jogged at a vigorous pace about 17 miles a week, putting in about three hours.

What was a bit surprising, Johnson said, was the benefits conferred to each group.

"What we found was that modest amounts of moderate intensity exercise [the low/moderate group] were very effective in improving metabolic syndrome," she said. Those who exercised the most, jogging 17 miles a week, gained a bit more benefit in terms of lowered metabolic syndrome scores, she said.

Those in the low amount/vigorous intensity group didn't improve their scores as much as those who did less-intense exercise for a longer period of time, the low amount/moderate intensity group.

Moderate intensity activity every day, or almost every day, may be better for metabolic syndrome risk reduction than more vigorous activity a few days a week, the researchers suggested.

All three groups of exercisers did have a reduction in their waistline circumference. Waist circumferences above 34.6 inches in women and 40.2 in men are a risk factor for metabolic syndrome, the researchers said.

The high amount/vigorous intensity group had the best reduction in body mass index (BMI, a ratio of weight to height). It went from an average of 29.2 to 28.4. A BMI of 30 and higher is termed obese.

So, the bottom line for middle-age, sedentary, overweight people? "If you tell them to go out for a brisk walk 30 minutes on most days of the week, they are highly likely to improve health and metabolic syndrome risk," Johnson said.

The new research confirms advice on exercise from the American College of Sports Medicine and the U.S. Centers for Disease Control and Prevention, she added.

"It confirms that exercise is beneficial," said Kerry Stewart, a professor of medicine at Johns Hopkins University School of Medicine, who also has done research on the topic.

"It confirms the benefit of exercise for reducing metabolic syndrome and all the risk factors that make up metabolic syndrome," he said. The surprise, he agreed, was that moderate activity may be enough.

SOURCES: Johanna Johnson, clinical researcher, Duke University Medical Center, Durham, N.C.; Kerry Stewart, Ed.D., professor of medicine, Johns Hopkins University School of Medicine, Baltimore; Dec. 15, 2007, American Journal of Cardiology

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