Abstract Background Population aging is a pressing global challenge, with approximately 700 million individuals aged 65 or older worldwide. Compared with younger adults, older adults face an elevated risk of cardiovascular disease and stroke. Existing research demonstrates that PA reduces all-cause mortality in older adults and favor health outcomes including cardiovascular disease, cognitive function, and fall prevention. However, many middle-aged and older adults change their physical activity (PA) intensity over time. Assessing the impact of PA on health outcomes based on a single measurement of PA intensity is inaccurate. This study aims to explore the relationship between changes in PA intensity and the incidence of stroke and heart disease (CVD), and to explore the mediative mechanisms. Methods Data were from the 2004/05 English Longitudinal Study of Ageing (ELSA) cohort (N=3035), participants aged ≥ 50 years and older, with CVD data tracked through 2019 and a second PA measurement conducted after 6 years. PA intensity in this study was assessed using self-reported measures and categorized into four levels according to the previous research: inactivity, low, moderate, and vigorous. Total cumulative PA intensity was calculated by summing the numerical values representing PA intensity across all three waves(Wave 2, Wave 4, and Wave6). Results Increased PA intensity (inactive/low to vigorous) is followed by a reduction in incident of CVD compared with those with constantly inactive/low PA intensity (HR= 0.43; 95% CI, 0.23-0.80), whereas a substantial decrease (vigorous to inactive/low) in PA was associated with higher risk of incident CVD (HR= 1.77; 95% CI, 1.11-2.83). An inverse association was observed between cumulative PA intensity and incident CVD, mediated by improvements in lipid metabolism, insulin resistance, and depressive symptoms. The HRs for cumulative high-intensity PA vs cumulative low-intensity PA were 0.78 (95% CI, 0.66-0.93) for incident CVD. Conclusions This study showed that the benefit of increasing PA intensity on incident CVD is significant, particularly for those who were physically inactive at baseline The reduction in incident CVD risk associated with cumulative PA intensity was mediated through improvements in lipid metabolism, insulin resistance, and depressive symptoms.Figure 1 Figure 2
Li et al. (Sat,) studied this question.