Finally, we were able to examine the influence of chronotype on the association between chronoactivity and CVD incidence.The study also has some limitations.Although having this information may lead to a better understanding of the observed association, according to the latest WHO report on physical activity, there is no effect difference between leisure of work-related activity on health.Fourth, accelerometer was only collected for seven days at baseline, and therefore does not take into account possible changes of physical activity timing during follow-up.Unfortunately, since these variables were collected several years before the accelerometer measurement period, we were not able to perform mediation analyses to sort this out.Therefore, they could lie in the causal pathway of the associations.Besides, given the observational nature of the study, we cannot rule out that residual confounding plays a role in our observations and we were not able to examine the causal relationship of this association.It is important to keep this in mind when interpreting the results from this study, especially those from the second adjustment model.Despite these limitations, this study adds to the rather unexplored field of research by its strengths and encourages future research on the causal relation between chronoactivity and CVD risk.When future studies are able to replicate our results as well as to demonstrate the direct health benefits of morning physical activity, societal challenges might influence the implementation of morning physical activity to benefit overall public health as previous research already demonstrated timing of physical activity influences already the participation rate in studies.When being validated and extensively metabolically characterized, these present results might suggest that time-dependent physical activity interventions might be an added beneficial behavioural factor to reach maximum health benefits and to lower the risk of CVD.contributed to the interpretation of the data.contributed to the funding acquisition.The drafting of the initial version of the paper was done by G.All authors critically revised the paper for important intellectual content.All authors read and approved the final paper.Data from the UK Biobank are available to researchers by application via the UK-Biobank online Access Management System.Prevalence and prevention of cardiovascular disease and diabetes mellitus.The physical activity guidelines for Americans.Behavioral counseling to promote a healthful diet and physical activity for cardiovascular disease prevention in adults without cardiovascular risk factors-US preventative services task force recommendation statement.The relationship between time of day of physical activity and obesity in older women.Time of exercise specifies the impact on muscle metabolic pathways and systemic energy homeostasis.Associations between timing of meals, physical activity, light exposure, and sleep with body mass Index in free-living adults.Effects of intermittent fasting on health, aging, and disease.Effects of the time of day of walking on dietary behaviour, body composition and aerobic fitness in post-menopausal women.Physiological and molecular dissection of daily variance in exercise capacity.Consistent morning exercise may be beneficial