It's common sense that someone who belongs to a gym may be in better shape than one who doesn’t. But just how much of a difference can ponying up for a club card really make? New research shows that people who belong to a gym are an astonishing 14 times more likely than nonmembers to meet the recommended weekly guidelines for both aerobic exercise and strength-training.
Kinesiologists from Iowa State University rounded up 405 adults ages 30 to 64 with no history of heart problems. Half belonged to a health club for at least one month prior to the study’s start; half had not held a gym membership for at least three months. The researchers measured everyone’s blood pressure, heart rate, body-mass index, waist circumference, and cardiorespiratory fitness. Next, they asked detailed questions about the participants’ exercise frequency and duration (whether in or outside the gym), how much time they spent sitting each day, and which types of everyday physical activities they engaged in, such a cleaning the house or carrying heavy loads at work.
After tabulating all the data, the researchers determined that gym members were 14 times more physically active overall and 10 times more likely to be sufficiently strength-trained. Gym members logged, on average, 484 minutes of exercise a week; nonmembers put in just 137 minutes. Looking at the findings another way, 75 percent of gym goers met the federal guidelines for both aerobic exercise (at least 150 minutes of moderate-intensity or 75 minutes of vigorous aerobic activity per week) and muscle-strengthening workouts (two or more days a week). Only 18 percent of nonmembers met these marks.
“We expected the gym members to be more physically active, but this was a much more dramatic difference than we anticipated,” says lead study author Elizabeth Schroeder, now a graduate assistant at the University of Illinois at Chicago. She wasn’t quite as surprised that members were more apt to strength-train, since they have fully stocked weight rooms at their disposal.
Besides outshining nonmembers in activity levels, the gym rats had far better cardiovascular profiles. They had lower odds of obesity, lower resting heart rates of roughly five beats per minute, and better cardiorespiratory fitness. Also, the gym-going guys’ waist circumferences were about 1.5 inches less than the men who didn’t belong to health clubs. And the longer they had memberships, the slimmer their bellies were. “Men have a tendency to carry more weight in their midsection, so in terms of overall health, this could be very beneficial,” Schroeder says.
Which all leads us to the question: Is owning a gym membership itself a motivator to exercise? Or are people who already prioritize exercise more likely to buy memberships? “I believe that people have different motivations for exercise, and for some, paying for a membership prompts them to attend the gym because they don’t want to waste money,” Schroeder says. “But I also believe that finding something you enjoy is most important and motivates you to continue that physical activity. Since gyms tend to offer a wide variety of options, such as ellipticals, weight machines, and group classes, you can find an activity you like and also, potentially, social support, which is important as well.”
Another interesting finding was that fitness center members didn’t get any less physical activity outside of the gym than nonmembers did. “We found it very interesting that members and nonmembers had very similar lifestyle physical activity levels,” says Schroeder. “This means members are not any less active outside the gym; rather, the gym provides additional physical activity, which fits in with them having better cardiovascular health outcomes. With heart disease being the number-one cause of death in America, these beneficial associations could lead to health care–cost reductions and greater quality of life.”