Does objectively measured light-intensity physical activity reduce the risk of cardiovascular mortality? A meta-analysis

Current physical activity guidelines emphasize little on light-intensity physical activity (LPA) in terms of reducing the risk of cardiovascular mortality. This meta-analysis aimed to bridge this gap by assessing their association using objectively measured LPA data.

Databases of PubMed and Scopus were searched to April 2020 for prospective cohort studies that reported the association of LPA assessed by activity monitors with the risk of cardiovascular mortality in the general population. Multivariable-adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) were pooled using a random-effects model. Dose–response and subgroup analyses were also performed. Six cohort studies with seven datasets enrolling 13 960 participants were included. LPA was all measured by accelerometers. The HR of LPA per 30 min/day for cardiovascular mortality was pooled to be 0.80 (95% CI 0.67–0.96). This association was non-linearly shaped (P_nonlinearity < 0.01) and unaffected by sex difference. Moreover, substituting LPA for sedentary time of 30 min/day lowered the risk of cardiovascular mortality by 16% (95% CI 0.73–0.96). Results showed further that LPA was inferior to moderate-to-vigorous physical activity in reducing the risk of cardiovascular mortality when performed with an equal time-length set at 30 min/day (HR 0.83 vs. 0.54, P_comparison = 0.046), but became comparable if at an equal activity-amount set at 150 metabolic equivalents-min/day (HR 0.67 vs. 0.54, P_comparison = 0.41).

LPA shows potential in reducing the risk of cardiovascular mortality, and interventions targeting at LPA improvement are worth being encouraged.