Many studies have suggested that regular physical activity, including walking for just 30 minutes a day at a moderate pace, may improve health. But the new research says it’s the intensity, rather than the duration, that makes the difference.
Specifically, fast walkers and joggers who exercised for two to four hours per week were up to 50% less likely to develop what's called metabolic syndrome. Participants who walked at a casual pace for about an hour a day made no difference in their risk to develop the syndrome.
Metabolic syndrome is the name for a cluster of risk factors that give rise to diabetes or heart disease. These risk factors include high blood pressure, high blood sugar, a high triglyceride (blood fat) level, a low HDL (good cholesterol) level, and belly fat.
The new study included more than 10,000 adults aged 21 to 98 from Copenhagen, Denmark. All the participants were quizzed on the amount of physical activity they did when the study started and were monitored for up to 10 years.
When the study began, 1 in 5 women and slightly more than 1 in 4 men had metabolic syndrome. Among women, close to 1 in 3 with metabolic syndrome was inactive. By contrast, 1 in 10 of the women who were extremely physically active had metabolic syndrome. The findings were similar among men in the study.
After 10 years of follow-up, about 15% of participants without metabolic syndrome developed it.
The risk was much lower among those who reported doing vigorous exercise than their counterparts who reported being inactive or doing light exercise, the study shows.
“Our results confirm the role of physical activity in reducing [metabolic syndrome] risk and suggest that intensity rather than volume of physical activity is important,” the study authors conclude.
The study did have some limitations. Namely, researchers did not look at participants' diets. Nutrition also plays a role in developing metabolic syndrome.