LAUSR

Cardiovascular diseases (CVD) are highly prevalent conditions that carry one of the highest morbidity and mortality burdens worldwide. Physical activity is a known protective factor for prevention of noncommunicable diseases such as CVD, and for allcause and cardiovascular mortality. Implementing prevention strategies to promote a physically active lifestyle should therefore be a public health priority. A recent systematic review suggests that patients with coronary heart disease who maintain or engage in physical activity can significantly reduce mortality risks compared to those inactive over time. Changes in physical activity describe trajectories that have the potential of better defining individual risk profiles compared to singletime assessments. Recently, growing interest has been drawn to the possibility of achieving cardiovascular benefits by engaging in physical activity also in latelife. 4 For most noncommunicable disease risk factors, longer duration of exposure is associated with higher chances of developing the disease. Similarly, if the exposure to a protective factor is too short, this may not exert any relevant beneficial effect. This could be the case of beginning physical activity in latelife. Numerous studies have shown that increasing physical exercise in midlife is associated with a significantly lower mortality risk, also among patients with CVD, 6 but evidence in latelife remainsscarce. Given the presence of ageing populations with a high prevalence of CVD, examining this association has great clinical and public health significance. A new study by Kang and colleagues published in this journal suggests that increasing physical exercise habits after an incident cardiovascular event in latelife can significantly reduce mortality risks. The authors selected data from 558 147 individuals, a 10% sample of the 5.5 million people aged ≥60 years present in the Korean National Health Insurance database, and included only those with clinical assessments between 2003 and 2012. Incident CVD was defined as any first occurrence of acute myocardial infarction, heart failure, or ischaemic stroke. Only people with a physical activity assessment within 2 years before and after CVD onset were included, and were categorised as persistent nonexercisers, exercise dropouts, new exercisers, and exercise maintainers. The final cohort comprised 6076 individuals, 50.6% men, with a median age of 72 years (IQR 69–76) and 3.8 years of followup (IQR 2.2–5.7). Allcause mortality rates and hazard ratios (HR), compared to persistent nonexercisers (incidence rate (IR) 4.8 per 100 personyears), were significantly lower for new exercisers (IR 3.5 per 100 personyears; HR 0.73, 95% CI 0.58 to 0.91) and exercise maintainers (IR 2.9 per 100 personyears; HR 0.53, 95% CI 0.38 to 0.73). Exercise dropouts had a similar allcause mortality rate (IR 4.6 per 100 personyears) and a nonsignificant risk difference compared to persistent nonexercisers (HR 0.92, 95% CI 0.70 to 1.22). The same association was present for cardiovascular and noncardiovascular deaths. When stratifying by age, this association was also found among participants younger and older than 75 years, and regardless of sex or baseline Charlson Comorbidity Index. Figure 1 reports some of the most relevant cardiovascular and mortality risk factors to outline part of the complexity of lifetime cumulative exposures. This study has focused on latelife exposures, examining physical activity trajectories before and after an incident cardiovascular event, but physical activity patterns, cumulative risk and protective factors could be affected by previous unmeasured earlyand midlife exposures. Nevertheless, these findings suggestthat regardless of what occurred earlier in life, among elderly cardiovascular patients, becoming or maintaining physically active can reduce allcause mortality by, respectively, 27% and 47%, compared to those inactive over time. This finding is of great public health importance as it suggests physical activity could contribute to significantly reduce the mortality burden among older cardiovascular patients. Several mechanisms could underlie the benefits of physical activity in latelife and contribute to explain the observed association; these include improved endothelial function and antiatherosclerotic effects. Endothelial dysfunction results in impaired nitric oxide production, abnormal vasoconstriction, inflammation and oxidative stress. Physical activity can promote the production of nitric oxide, and consequent vasodilation. Exercise is also associated with reduced atherogenic lipid profiles, lower blood pressure, and decreased risk of insulin resistance. These are all wellknown protective factors for CVD, although their benefits are not only limited to reducing the incidence of the disease, but also improve prognosis. However, an indepth understanding of the underlying pathophysiological mechanisms is still missing. There are, nonetheless, some limitations inherent to this study. First, the absence of an assessment of the severity of patients’