Muscle-strengthening activities are associated with a reduced risk of CVD, cancer and all-cause mortality independent of aerobic activity
Participating in muscle-strengthening activities, independent of aerobics, is associated with a lower risk of cardiovascular disease (CVD), total cancer and all-cause mortality. This was the conclusion of a meta-analysis by researchers from the Department of Medicine and Science in Sports and Exercise, Tohoku University Graduate School of Medicine, Miyagi, Japan.
The importance of increasing muscle strength is well-recognised and the World Health Organization recommends regular muscle-strengthening activity for all age groups. The importance of muscle-strengthening activities was highlighted in a 2018 review which concluded that higher levels of upper- and lower-body muscular strength are associated with a lower risk of mortality in the adult population, regardless of age and follow-up period. Moreover, grip strength, which is a marker for overall strength, has also been found to be an independent predictor of all-cause mortality and cardiovascular diseases.
Although the importance of aerobic activities for reducing CVD risk and all-cause mortality has been widely accepted for many years, the relationship with muscular strength has been less well studied. For the present analysis, the Japanese team focused on the association between muscle-strengthening activities and the risk of CVD, cancer and mortality in adults. However, they were also interested trying to determine the dose-response relationship with health outcomes and whether there were synergistic benefits from combing muscle strengthening and aerobic activities.
The team searched all the major databases from inception to 2020 for studies which considered the health outcomes from muscle strengthening activities in those without severe health conditions such as cancer at baseline.
Muscle strengthening activities and health outcomes
A total of 16 studies were included in the final analysis which covered all-cause mortality (8), CVD (9), total cancer (7), type 2 diabetes (5) and site-specific cancers (2). The number of participants varied between 3809 to 479,856 and the median duration of follow-up was 25.2 years and included patients 18 to 97 years of age.
Among studies which considered all-cause mortality, muscle-strengthening activities were associated with a 15% reduced risk of death (Relative risk, RR = 0.85, 95% CI 0.79 – 0.93, p < 0.001). With respect to the duration of activities, the lowest RR was seen at 40 minutes/week (RR = 0.83, 95% CI 0.79 – 0.86). Combing muscle and aerobic activities led to a 40% lower mortality risk (RR = 0.60, 95% CI 0.54 – 0.67) compared to no activity.
For CVD, there was a 17% lower risk from undertaking muscle-strengthening exercises (RR = 0.83, 95% CI 0.73 – 0.93) and the lowest relative risk occurred with training for at least 60 minutes/week (RR = 0.82, 95% CI 0.76 – 0.90).
Finally, muscle-strengthening activities led to a 12% lower risk of total cancer incidence (RR = 0.88) and a 17% lower incidence of diabetes (RR = 0.83).
Discussing their findings, the authors noted that there was a J-shaped relationship between muscle-strengthening activities and all-cause, CVD and total cancer mortality, with the greatest benefit (i.e., highest risk reduction) after 30 to 60 minutes/week of activities.
They concluded that the greatest benefit was accrued from combining muscle and aerobic activities although added the caveat that since the available data are currently limited, further studies are required to increase the certainty of the evidence.
Momma H et al. Muscle-strengthening activities are associated with lower risk and mortality in major non-communicable diseases: a systematic review and meta-analysis of cohort studies Br J Sports Med 2022