Adults who were most physically active in the late morning had a 16% decreased risk of coronary artery disease (CAD) and a 17% decreased risk of stroke compared to those who were most active midday, according to a new study.
The findings—which were consistent regardless of total mean daily physical activity level—were published in the European Journal of Preventive Cardiology.
“It is well established that exercise is good for heart health, and our study now indicates that morning activity seems to be most beneficial,” said first study author Gali Albalak, PhD candidate, Leiden University Medical Center, Netherlands, in an ESC press release. “The findings were particularly pronounced in women, and applied to both early birds and night owls.”
Albalak and colleagues used data from the UK Biobank to examine the association between intraday patterns of physical activity and cardiovascular disease (CVD) incidence. Included in the study were 86 657 adults aged 42 to 78 years who did not have a prior diagnosis of CVD at baseline. Mean age was 61.6 years and 58% were women.
Participants wore an activity tracker on their wrist for 7 consecutive days and were followed for a period of 6 years for incident CVD, which was defined for the purpose of the study as the first hospital admission or death related to CAD or stroke.
During the follow-up period, 2911 participants developed CAD and 796 had a stroke, according to researchers. After comparing peak physical activity times across 24 hours, investigators observed that being most active between 8 am and 11 am was associated with the lowest risks of both CAD and stroke.
In a second analysis, the team divided participants into the following 4 groups based on the peak time of physical activity:
Associations between peak time and incident CVD were analyzed using midday as the reference group, according to investigators.
After adjusting for age and sex, results showed that participants who were most active in the early morning (group 2) or late morning (group 3) had 11% and 16% lower risks of incident CAD, respectively, compared to the reference group (group 1). Also, adults in group 3 had a 17% decreased risk of incident stroke compared with the reference group. These effects were more pronounced in women (P-value for interaction=.001).
The results were consistent regardless of the total amount of daily physical activity and whether participants described themselves as a morning person or evening person, according to the study.
“This was an observational study and therefore we cannot explain why the associations were more marked in women,” stated Albalak. “Our findings add to the evidence on the health benefits of being physically active by suggesting that morning activity, and especially late morning, may be the most advantageous. It is too early for formal advice to prioritize morning exercise as this is quite a new field of research. But we hope that one day we can refine current recommendations simply by adding one line: ‘when exercising, it’s advised to do so in the morning.’”
Reference: Albalak G, Stijntjes M, van Bodegom D, et al. Setting your clock: Associations between timing of objective physical activity and cardiovascular disease risk in the general population. Eur J Prev Cardiol. Printed online ahead of print November 14, 2022. doi:10.1093/eurjpc/zwac239.