Long-term studies suggest that 90 to 120 minutes of strength (resistance) training each week may be the ideal range to reduce mortality risk. The study was published online. British Journal of Sports Medicinefollowed participants for up to 30 years.
The effects were even greater when strength training was combined with aerobic exercise. However, researchers found that doing more than 120 minutes of strength training per week did not provide any additional benefits. This level of exercise was associated with 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
Although the life-extending effects of aerobic exercise are well established, the impact of muscle-strengthening activities on overall and specific mortality is less clear. Researchers wanted to determine whether strength training alone or in combination with aerobic exercise could influence these risks.
To find out, 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). A total of 147,374 people (31,540 men and 115,834 women) participated in the study.
Every two years, participants reported how much time they spent each week doing strength training and aerobic exercise. Aerobic exercise includes brisk walking, running, jogging, swimming, cycling, tennis, squash, strenuous outdoor work, and climbing stairs. Strength training includes exercises that use weights or body weight, such as push-ups, squats, and lunges.
The average age of participants at the start of the study was 54 years. Those who reported higher levels of strength training were generally younger, weighed less, practiced a healthier lifestyle, and engaged in more aerobic exercise than those who did not strength train.
What researchers discovered
Approximately three-quarters (74%) of participants exceeded the recommended 150 minutes of moderate-intensity aerobic exercise per week, which equates to 7.5 MET hours over time. MET measures how many calories are burned during physical activity compared to resting.
Almost half of the participants (46%) reported doing some form of strength training.
During 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 influence the results, participants who did 90 to 119 minutes of strength training per week had a 13% lower risk of death from any cause. No further reduction in risk was observed beyond 120 minutes per week.
The 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 with lower amounts of strength training. Participants who exercised between 1 and 29 minutes per week had a 21% lower risk of dying from cancer, and participants who exercised between 30 and 59 minutes per week had an 18% lower risk of dying from cancer.
The power of combining cardio and strength training
Compared to people who did less than 7.5 MET hours of aerobic exercise per week and no strength training, participants who did only strength training for 1 to 59 minutes or 60 to 119 minutes per week had a 7 to 11% lower risk of death.
Aerobic exercise itself also had a significant effect. Exceeding 7.5 MET hours per week reduces the risk of death by 26-43%.
Those who combined high levels of aerobic exercise with strength training had the lowest risk of death. People who combined 30 to 44 MET hours of aerobic exercise and 60 to 119 minutes of strength training per week had a 45% lower risk of death.
Even greater reductions were observed in participants who performed 45 MET hours or more of aerobic exercise per week. In that group, the risk of death was 53% to 58% lower, regardless of the amount of strength training.
Important limitations
The researchers stressed that this was an observational study, meaning they could not prove that strength training directly caused a reduction in mortality risk.
They also pointed out some limitations. Exercise habits are self-reported and may be inaccurate. This analysis does not include specific strength training such as gymnastics or Pilates. Additionally, no information was available regarding the duration of individual training or the intensity of the strength training sessions, factors that may have influenced the results.
Despite these limitations, the researchers concluded that:
“Our findings of different dose-response relationships between all-cause and cause-specific mortality with long-term resistance training suggest that different amounts of resistance training may be required to optimize overall outcome benefits.
“The observed pattern that adding resistance training further reduces mortality risk at all levels of aerobic exercise up to 45 MET hours per week supports current recommendations to encourage both types of activity to maximize mortality benefits.”
