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
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 for Metabolic Syndrome
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.
Be sure to check with your doctor before starting a new exercise program, especially if you've been on the sidelines for a while.