EXERCISING in the morning is associated with the lowest risk of heart disease and stroke, according to an observational study by Gali Albalak, Leiden University Medical Centre (LUMC), the Netherlands, and colleagues. While it is already well known that exercise is good for heart health, this new data indicates that the time a person engages in physical activity is important.
Using data from the UK Biobank, the study included 86,657 adults aged 42–78 (average age: 62) years who did not have cardiovascular disease at baseline. Participants wore an activity tracker on their wrist for 7 consecutive days and were followed for incident cardiovascular disease, defined as their first coronary artery disease- or stroke-related hospital admission or death.
The researchers categorised the participants depending on the time that they exercised as midday, early morning (approximately 8 a.m.), late morning (approximately 10 a.m.), and evening (approximately 7 p.m.). These categories were chosen according to peak times of activity in the study’s population instead of being predetermined before the study, and the midday group was used for reference during analysis.
During the follow-up of 6–8 years, 2,911 participants were diagnosed with coronary artery disease and 796 had a stroke. Participants who exercised in the early and late morning had an 11% and 16% lower risk of incident coronary artery disease, respectively, compared with the reference group. Furthermore, those exercising in the late morning had a 17% lower risk of incident stroke compared with the reference group.
Exercising in the morning appears to be particularly beneficial to females, who had a 22% and 24% lower risk to incident coronary artery disease when exercising in the early or late morning, respectively, compared with the reference group. Moreover, females exercising in the late morning had a 35% lower risk of incident stroke. Albalak admitted that, as an observational study, they cannot explain why females should be particularly affected by the time that they exercise; however, they stated: “Our study now indicates that morning activity seems to be [the] most beneficial.”
While the study indicates that females may benefit in particular, the findings were consistent regardless of the total amount of exercise or whether the participants described themselves as an ‘early bird’ or a ‘night owl’.