Intensity of Physical Activity and Cardiovascular Events in Adults: A Systematic Review and Meta-Analysis

Objective: To determine whether the cardiovascular protective effects of physical activity (PA) differ between moderate and vigorous intensities in adults without pre-existing cardiovascular disease (CVD).Material and Methods: A systematic search was performed in PubMed, Scopus, and Web of Science for studies published between 1990 and 2024. Eligible studies were prospective cohorts that examined the association between PA intensity—expressed in metabolic equivalent tasks (METs)—and incident CVD outcomes. PA was categorized as moderate (3–5.9 METs) or vigorous (≥6 METs). Studies included adult populations without prior CVD. Pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using a random-effects model. Heterogeneity was assessed using the I² statistic, and sensitivity analyses were conducted to evaluate result robustness. Results: A total of 1,057,895 participants were included, with a mean follow-up of 10.4 years. Moderate-intensity PA was associated with a pooled HR of 0.84 (95% CI: 0.73–0.98), while vigorous-intensity PA had a pooled HR of 0.84 (95% CI: 0.78–0.91), suggesting similar cardiovascular benefits. Moderate heterogeneity was present (I²=66.4%), potentially due to varying definitions of intensity and adjustment factors across studies. Sensitivity analyses supported the stability of results, and publication bias was minimal.Conclusion: Both moderate and vigorous physical activity are associated with comparable reductions in CVD risk. These findings reinforce the current public health guidelines recommending either 150–300 minutes of moderate or 75–150 minutes of vigorous PA per week for cardiovascular prevention.