Past research has similarly pointed to the long-term health benefits of strength training, but the new analysis, published February 28 in the British Journal of Sports Medicine, considered more recent data, up to June 2021. The data suggests that 30 minutes to a full hour of weekly strength training was the amount linked with the most benefit in terms of longevity before the advantage plateaued (and with longer amounts of weekly strength training, it did actually start to decrease). “This provides a potential optimal dose of muscle-strengthening activities,” says the lead study author, Haruki Momma, PhD, a lecturer in the department of medicine and science in sports and exercise at the Tohoku University Graduate School of Medicine in Japan. Current U.S. exercise guidelines recommend muscle-strengthening workouts twice a week but don’t specify how long these workouts should be. Dr. Momma and others say the new data doesn’t warrant a time-based recommendation for strength training to update to current physical activity guidelines, but it’s a step toward doing so.
Regular Strength Training Lowered Risk of Death From Cancer, Heart Disease, and More
For the study, Momma and colleagues examined data pooled from 16 earlier studies to get a clearer picture of how muscle-strengthening and aerobic exercise might influence longevity and the risk of death from several common health problems, including heart disease, diabetes, and cancer. Many of these smaller studies followed participants for several decades to see how physical activity influenced their life span. The studies ranged in size from about 3,800 to 478,000 participants ages 18 to 98. Participants who did any type or amount of muscle-strengthening exercise had a 15 percent lower risk of premature death from all causes, the study found. Weight training was linked to a 10 to 17 percent lower chance of early death from diabetes, cancer, and cardiovascular disease. But more weight training didn’t necessarily lead to the biggest benefit. Researchers found that the most benefit — a 10 to 20 percent reduction in the risk of early death from all causes and from cancer and heart disease specifically — occurred when people did approximately 30 to 60 minutes of muscle-building workouts per week. After that first hour, there was a slight benefit for roughly one more hour per week. But beyond two hours, more weight training each week was actually associated with an increased chance of dying young. Unsurprisingly, adding aerobic exercise to weekly strength training yielded the biggest longevity benefit. Compared with being inactive, doing both aerobic exercise and strength training on a weekly basis was associated with 40 percent lower odds of premature death from all causes, the study found. This combination of workouts was also linked to a 46 percent lower risk of death from cardiovascular disease and a 28 percent lower risk of cancer death. There are some caveats to these findings. The study shows a link between these different types of exercise and mortality, but doesn’t prove that one necessarily causes the other. Factors that weren’t controlled for in the studies could be at play. And, the analysis was based on self-reported exercise habits, rather than workouts objectively measured by fitness trackers or other gadgets, making it possible people misrepresented their physical activity levels.
Still Not Enough Data for an Ideal Weekly Strength Training Dose
The results from this new review largely align with other data on the question of how much strength training is linked with long-term health benefits. A study published in 2020 in the journal Preventing Chronic Disease, for example, examined longevity and exercise data for more than 72,000 adults. That study found a 10 to 12 percent lower risk of premature death from all causes with weight training up to two hours per week; no benefit was seen with more time. The U.S. Department of Health and Human Services (HHS) Physical Activity Guidelines for Adults recommend muscle-strengthening exercises for all the major muscle groups at least twice per week (which could include lifting weights, using resistance bands, doing exercises like push-ups or sit-ups, or practicing some types of yoga). The guidelines also call for adults to get 150 minutes of moderate-intensity aerobic exercise (like walking or biking) or 75 minutes of vigorous-intensity activity (like running or lap swimming) each week. The new study adds to the evidence from earlier research suggesting there may be an optimal amount of weight training to do regardless of how much aerobic exercise people get. But it would be premature to change the guidelines, says I-Min Lee, MD, ScD, a professor of epidemiology at the Harvard T.H. Chan School of Public Health and Brigham and Women’s Hospital in Boston who studies exercise and disease prevention. “I think it is too early to have time-based guidelines; we need more research,” says Dr. Lee, who wasn’t involved in the new analysis. But she adds that two 30-minute strength workouts per week would align with the current guidelines if you’re targeting all the major muscle groups in those workouts. “Muscle-strengthening exercises lead to increased muscle mass and muscle strength, which help improve physical functioning,” Lee says. “Such exercises also improve glucose metabolism, enhance maintenance of healthy body weight, and help improve cardiovascular risk factors such as blood pressure. … All these factors lead to lower risks of cardiovascular disease, cancer, and diabetes, which lowers mortality risk.”
