Do vigorous-intensity and moderate-intensity physical activities reduce mortality to the same extent? A systematic review and meta-analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of prospective observational cohort studies
PubMed 33178440 · doi:10.1136/bmjsem-2020-000775
What was done
A systematic review (PROSPERO CRD42019138995) and meta-analysis searched three databases through April 14, 2020, for prospective studies evaluating moderate-intensity (3-5.9 METs) versus vigorous-intensity (≥6 METs) physical activity in relation to all-cause or cause-specific mortality. Studies were required to adjust for total physical activity and baseline comorbidities. Studies recruiting exclusively diseased patients or using inactive reference groups were excluded. Risk of bias was evaluated with the ROBINS tool.
What was found
Five studies (yielding seven sex-specific cohorts) were pooled. When controlling for total physical activity volume, vigorous-intensity activity was not associated with a larger reduction in all-cause mortality compared with moderate-intensity activity (HR 0.95, 95% CI 0.83 to 1.09). Excluding one study with critical risk of bias yielded a similar result (HR 0.98, 95% CI 0.85 to 1.12). Meta-analyses for cancer and cardiovascular mortality could not be conducted due to the limited number of studies.
Why it matters
These findings suggest that when total physical activity volume is held constant, vigorous exercise does not confer an additional survival benefit over moderate exercise in prospective cohort data.
Limits
Only five studies met inclusion criteria, preventing meta-analysis of cancer or cardiovascular mortality. The synthesized literature is purely observational, with one included study judged at critical risk of bias, and the authors note existing methodological flaws limit definitive conclusions.
Cited by
- supports In physical activity guidelines, moderate-intensity physical activity is defined as 3.0 to 5.9 metabolic equivalents (METs) or 5 to 6 on a 10-point perceived exertion scale.