Half an hour of muscle strengthening activity such as lifting weights, push-ups or heavy gardening each week could help reduce the risk of dying from any cause by as much as a fifth, according to a new global analysis of studies conducted over three decades.
Health guidelines recommend muscle strengthening activities, primarily because of the benefits for musculoskeletal health. Previous research has indicated a link to a lower risk of death, but until now experts did not know what the optimal “dose” might be.
To try to find out, researchers in Japan scoured databases for relevant studies that included adults without major health issues who had been monitored for at least two years. The final analysis included 16 studies, the earliest of which was published in 2012. Most were carried out in the US, with the rest of England, Scotland, Australia and Japan. The maximum monitoring period lasted 25 years.
The analysis found that 30 to 60 minutes of muscle strengthening activity every week is linked to a 10% to 20% lower risk of death from all causes, and from heart disease and cancer. The results were published in the British Journal of Sports Medicine.
The findings were independent of aerobic exercise. But the analysis pointed to a J-shaped curve for most outcomes, with no conclusive evidence that more than an hour a week of muscle strengthening reduced the risk any further.
UK physical activity guidelines say muscle strengthening activities can include carrying heavy shopping bags, yoga, pilates, tai chi, lifting weights, working with resistance bands, doing exercises that use your own body weight such as push-ups and sit-ups, heavy gardening such as digging and shovelling, wheeling a wheelchair or lifting and carrying children.
It is recommended for adults to do strengthening activities working all the major muscle groups at least two days a week as well as doing at least 150 minutes of moderate intensity activity each week. The researchers found people reap the most benefits when they regularly do both.
The analysis included studies with participant numbers varying from about 4,000 to 480,000, and ranged in age from 18 to 97. It showed that muscle strengthening was associated with a 10% to 17% lower risk of death from any cause, heart disease, cancer and diabetes.
Researchers said the maximum risk reduction of between 10% and 20% was found at 30 to 60 minutes a week of muscle strengthening activities for death from any cause, heart disease and cancer. An L-shaped association was observed for diabetes, with a large risk reduction up to 60 minutes/week of muscle strengthening activities, after which there was a gradual tapering off.
Joint analysis of muscle strengthening and aerobic activities showed the reduction in risk of death from any cause, heart disease and cancer was even greater when these two types of activities were combined: 40%, 46%, and 28% lower, respectively.
The researchers acknowledged limitations to their findings, the main one of which was that data from only a few studies were pooled for each of the outcomes studied. “Given that the available data are limited, further studies – such as studies focusing on a more diverse population – are needed to increase the certainty of the evidence,” they concluded.