A recent study conducted by researchers at the Harvard T.H. Chan School of Public Health has identified an optimal weekly duration of resistance training associated with lower risks of premature death. The analysis suggests that spending between 90 and 119 minutes per week lifting weights correlates with the greatest longevity benefits, independent of aerobic exercise levels.

The study drew on data from nearly 150,000 men and women who participated in long-term health cohorts, primarily composed of nurses and healthcare professionals. Participants provided information about their weekly exercise habits, including aerobic activities such as walking, running, and cycling, as well as resistance training involving weight machines and free weights. Researchers then examined mortality records over an approximate 30-year follow-up period to assess links between different exercise patterns and risk of death.

Findings indicate that engaging in resistance training for 90 to 119 minutes weekly was associated with a 13 percent reduction in all-cause mortality and a 19 percent reduction in deaths related to heart disease. The study also revealed a particularly pronounced decrease—27 percent—in deaths attributed to neurological conditions such as dementia. Benefits were observed even with smaller amounts of weight training, although the protective effects were less pronounced below the identified range. Extending training beyond 119 minutes per week did not result in additional mortality reductions but did not increase risks either.

Importantly, the study controlled for levels of aerobic exercise, suggesting that the longevity advantages of resistance training are additive. Individuals who combined both aerobic activities and resistance workouts generally experienced the lowest mortality risk overall. "People who combined aerobic exercise with resistance training generally had the lowest mortality risk," said Yiwen Zhang, a postdoctoral researcher who led the study.

Despite the robust associations, some questions remain unanswered. The study does not clarify the optimal structure of resistance training sessions—whether longer, less frequent workouts surpass shorter, more frequent ones—or differentiate between lifting heavier weights versus lighter resistance or body-weight exercises such as push-ups. Additionally, the biological mechanisms underlying the protective effects are not fully understood, although previous research suggests that maintaining muscle mass supports mobility, metabolic health, and brain function, potentially reducing the risk of falls and cognitive decline.

David Scott, an exercise scientist at Deakin University in Australia not involved with the research, noted the study’s strength lies in its large sample size and extended follow-up, alongside repeated measures of individuals’ exercise habits, calling the findings “convincing.” Edward Giovannucci, professor of nutrition and epidemiology and senior author, emphasized the novelty of quantifying resistance exercise’s impact on long-term mortality, saying that “less is known about how resistance exercise relates to long-term mortality risks.”

While national physical activity guidelines recommend at least two days per week of muscle-strengthening exercises, they lack specific guidance on duration or intensity. This study contributes valuable data toward defining an evidence-based “sweet spot” for resistance training aimed at promoting longevity. Both Zhang and Giovannucci said they plan to continue resistance training themselves, reflecting their own findings.

Further research is needed to determine the best approaches to weight training and to unravel the underlying physiological pathways that mediate its benefits for lifespan extension.