Scientists found the strength training sweet spot for a longer life

The benefits were even greater when strength training was combined with aerobic exercise. However, researchers found no additional advantage from doing more than 120 minutes of strength training per week. That level of exercise was linked to a 19% lower risk of death from cardiovascular disease and a 27% lower risk of death from neurological disease.

Strength Training and Long-Term Health

While the life-extending benefits of aerobic exercise are well established, the impact of muscle-strengthening activities on overall mortality and specific causes of death has been less clear. Researchers wanted to determine whether strength training alone, or combined with aerobic exercise, could influence those risks.

To investigate, they analyzed data collected over three decades from three major studies: the Health Professionals Follow-up Study (1992-2022), the Nurses' Health Study (2002-21), and the Nurses' Health Study II (2003-21). Together, the studies included 147,374 participants (31,540 men and 115,834 women).

Every two years, participants reported how much time they spent each week doing strength training and aerobic exercise. Aerobic activities included brisk walking, running, jogging, swimming, cycling, tennis, squash, strenuous outdoor work, and stair climbing. Strength training included exercises using weights or body weight, such as press ups, squats, and lunges.

At the start of the study, participants were an average of 54 years old. Those who reported higher levels of strength training were generally younger, weighed less, followed healthier lifestyles, and engaged in more aerobic activity than those who did no strength training.

What the Researchers Found

About three quarters (74%) of participants exceeded the recommended 150 minutes of moderate intensity aerobic exercise per week, equivalent to 7.5 MET hours over the long term. METs measure how many calories are burned during physical activity compared with resting.

Nearly half (46%) of participants reported doing some form of strength training.

Over the 30-year follow-up period, 35,798 participants died. Researchers found that higher long-term levels of weekly strength training were associated with a lower risk of death.

After accounting for other factors that could affect the results, participants who performed 90-119 minutes of strength training per week had a 13% lower risk of death from any cause. No additional reduction in risk was observed above 120 minutes per week.

That same 90-119 minute range was also associated with a 19% lower risk of death from cardiovascular disease and a 27% lower risk of death from neurological disease.

Cancer-related benefits appeared at lower amounts of strength training. Participants who performed 1-29 minutes per week had a 21% lower risk of cancer death, while those doing 30-59 minutes per week had an 18% lower risk.

The Power of Combining Cardio and Strength Training

Compared with people who did less than 7.5 MET hours of aerobic activity per week and no strength training, participants who performed strength training alone for 1-59 minutes or 60-119 minutes per week had a 7-11% lower risk of death.

Aerobic exercise on its own also showed strong benefits. Any amount above 7.5 MET hours per week was associated with a 26-43% lower risk of death.

The lowest mortality risk was seen among people who combined high levels of aerobic exercise with strength training. Those who accumulated 30-44 MET hours of aerobic activity per week and 60-119 minutes of strength training had a 45% lower risk of death.

Even greater reductions were observed among participants who performed 45+ MET hours of aerobic activity per week. In that group, the risk of death was 53% to 58% lower regardless of how much strength training they did.

Important Limitations

The researchers emphasized that this was an observational study, meaning it cannot prove that strength training directly caused the reductions in mortality risk.

They also noted several limitations. Exercise habits were self reported, which can introduce inaccuracies. The analysis did not include certain forms of strength training, such as calisthenics and Pilates. In addition, information was not available on the duration of individual workouts or the intensity of strength training sessions, factors that could have influenced the results.

Despite those limitations, the researchers concluded:

"Our findings on different dose-response relationships between long-term resistance training with all-cause and cause-specific mortality suggest that different amounts of resistance training may be needed to optimize benefits across outcomes.

"The observed pattern that adding resistance training further reduced mortality risk across all levels of aerobic activity up to 45 MET hours/week supports current recommendations encouraging both types of activity to maximize mortality benefits."