Science confirms the obvious about fitness, health and gym usage.

Joining a gym is a good thing. Everyone gets that, right? The benefits gym­-goers get might make non-gym-goers sign-up at their local fitness centers (or reactivate those memberships that slipped their minds).

Need research? Iowa State University scientists recruited 405 healthy adults, half gym-goers for at least 30 days, and half non-gym-goers for at least three months. Subjects had resting blood pressure, heart rate, and body mass index measured, and chronicled time spent exercising, sitting, and doing various lifestyle activities weekly.

After analysis, researchers identified which participants met national recommended physical activity guidelines: 150 minutes of moderate or 75 minutes of vigorous aerobic activity each week, including at least two days of muscle-strengthening activities.

The difference was “pretty dramatic and surprising,” says corresponding author Duck-chul Lee, an assistant professor of kinesiology. Non-gym-goers only exercised an average of 137 minutes weekly, while gym-goers logged a weekly average of 484 minutes. Only 18% of non-gym-goers met guidelines for both physical activity and strength training, compared to 75% of members.

Overall, the researchers calculated, a gym membership was related to 14 times higher odds of meeting weekly physical activity guidelines. The results were similar in both men and women and were adjusted for health issues like high cholesterol, arthritis, and asthma.

Not only did regular gym-goers exercise more, they were less likely to be obese and had better cardiovascular readings. Regular gym-goers tended to have lower resting heart rates, higher cardiorespiratory fitness, and smaller waistline measurements than non-gym-goers.

Before the study, Lee and his colleagues suspected that gym members might be more sedentary outside the gym than non-gym-members. “We thought maybe they’d be more tired, or be satisfied they’d done enough for the day.”

According to their findings: nope. “Physical activity outside of the gym was the same for both groups,” he says, “For non-members, joining a gym really may increase overall activity levels.”

Lee says the study’s cross-sectional design suggests it’s also possible that people who are more active are simply more likely to join a gym. And while the study covered a city with many gym options, people in rural areas may find it more difficult to visit a gym regularly.

But you gotta go! “It’s true that some people with a gym membership do not go regularly, just as some people who don’t have memberships still go out and run or bike and still meet the guidelines,” Lee says. Some measurements were taken at gyms, assuring that memberships were in use during this research study.

But Lee says the study supports the idea that joining a gym can help people who aren’t getting enough exercise on their own. Only half of Americans get the recommended amount of aerobic activity, the study reports, and only about 20% meet the guidelines for strength training.

“At the gym, you can use the weights or the resistance machines,” Lee says. “In real-life, there aren’t a lot of day-to-day activities that improve muscle.” (The researchers did not ask participants if they had weights or other fitness equipment at home.)

The researchers report no conflicts of interest and no financial stake in any health clubs or fitness clubs. The study is published in the journal PLOS ONE.

Elizabeth Schroeder lead researcher and a former Iowa State grad student, says gym memberships can have more benefits than just weight loss, and she hopes these findings prompt people to join a gym or fitness studio to fit their needs.

“Some people may enjoy being at a gym and doing their own workout routine, while others may desire group classes that potentially foster a social aspect, fun environment, consistent schedule, and a workout designed for you,” says Schroeder. “Either way, they both involve accumulating physical activity, and that’s the goal.”

 
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