Strength training exercise may lower disease risks

Middle aged adults who do even a small amount of regular strength training exercise may be lowering their risk of so-called metabolic syndrome - itself a risk factor for both heart disease and diabetes, a recent study suggests.

People with at least three unfavorable health stats from a list that includes large waist size, high blood pressure or triglycerides, high blood sugar or low “good” cholesterol are said to have metabolic syndrome, and are at increased risk of going on to develop diabetes, heart disease or both.

But researchers found that when generally healthy people did strength-building exercise for less than an hour a week they had 29 percent lower odds of developing metabolic syndrome than their peers who did no resistance exercise at all.

“You already get health benefits with even a low amount of resistance exercise per week, which is good news for people with a very busy lifestyle,” said lead author Esmee Bakker of Radboud University Medical Center in Nijmegen, The Netherlands.

Although previous studies have reported how aerobic exercise, such as running, walking and swimming, reduce metabolic syndrome, few studies have looked at resistance exercise alone.

The US government’s Physical Activity Guidelines for Americans suggest that adults should do “muscle-strengthening activities that are moderate or high intensity and involve all major muscle groups on 2 or more days a week” and aerobic exercise 150 or more minutes each week.

“A modest amount of resistance exercise, such as two 30-minute sessions per week, has beneficial effects,” Bakker said. “We think that resistance exercise, in addition to aerobic exercise, should be included in standard medical recommendations to prevent metabolic syndrome.”

Bakker and colleagues analyzed data on more than 7,400 people who participated in medical examinations at the Cooper Clinic in Dallas, Texas, between 1987 and 2006. They ranged in age from mid-30s to mid-50s at the time of their examinations.

The research team found that 1,147 participants, or 15 percent, had developed metabolic syndrome during the follow-up period. Meeting the resistance exercise guideline of two or more days per week reduced risk of metabolic syndrome by 17 percent overall, compared to doing no resistance exercise. Those who met both aerobic and resistance training guidelines had a 25 percent lower risk of developing metabolic syndrome.

“This result was independent of other healthy behaviors, such as not smoking,” Bakker said. “It also made little difference if people did resistance exercise only on weekends or spread throughout the week.”

Bakker and colleagues plan to study the effect of resistance training on other health outcomes, such as the heart health benefits of a one-year resistance exercise training program. They also want to examine the long-term effects of different types and intensities of strength training on metabolic syndrome.

“The real next step is to see how we can get people to exercise,” said Paul Thompson of the University of Connecticut in Hartford, who wasn’t involved with the study.

“We can talk about the right dose and intensity, but it’s clear that in most studies, doing something is better than nothing,” he told. “Most people do nothing, and the key is to get them to do anything.”

One limitation of the study is that it relies on self-reported survey data, which could bias the results. Thompson also cautions that some patients of the Dallas clinic are relatively more affluent than the rest of the country, so the results might not apply more generally.

“The increasing American girth has increased metabolic syndrome, which leads to insulin resistance and makes it harder for insulin to work,” he noted.

Thompson is studying how exercise affects people who have a tendency toward metabolic syndrome and ways they can work against a genetic disposition toward diabetes and hypertension, for example.

“Everybody should have some exercise,” he said. “Play with the dog or grand kids, do yard work or go for a walk. Just do something for 30 minutes every day.”