Association of the time of day of peak physical activity with cardiovascular mortality: Findings from the UK Biobank study

ABSTRACT

Cardiovascular physiology and pathophysiology display pronounced circadian rhythms. The study is designed to examine whether the time of day of physical activity is associated with cardiovascular mortality. We analyzed 94,489 UK Biobank adults with objectively measured physical activity, including 53,328 morning-type participants and 30,962 evening-type participants based on self-reported chronotypes. The time of day of peak physical activity was categorized using a machine learning algorithm: early morning (n = 18,477), late morning (n = 25,700), midday (reference) (n = 27,803), and night (n = 22,509). Hazard ratios of cardiovascular mortality were examined using the Cox proportional hazards model. During a median follow-up of 6.9 years (interquartile range, 6.3–7.4 years), we identified 629 cardiovascular deaths. The hazard of cardiovascular mortality was elevated in the early morning group (hazard ratio = 1.56, 95% Confidence Interval [1.23–1.98]) and night group (1.49, [1.18–1.88]) but not in the late morning group (1.21, [0.98–1.47]) compared to the referent midday group. In the chronotype-stratified analysis, the increased cardiovascular mortality in the morning group was only observed in the evening-type participants, while the increased cardiovascular mortality in the night group was only observed in the morning-type participants. In conclusion, optimizing the timing of peak physical activity according to cardiovascular circadian rhythms and individual chronotypes could be a potential therapeutic target that brings additional health benefits.

KEYWORDS:

• Cohort study
• timing of physical activity
• chronotype
• circadian rhythm
• cardiovascular physiology
• machine learning
• accelerometry

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data underlying this article were provided by the UK Biobank Access Management Team by permission. Data are available for approved researchers with permission of the UK Biobank Access Management Team. https://www.ukbiobank.ac.uk/enable-your-research/apply-for-access.https://www.ukbiobank.ac.uk/enable-your-research/apply-for-access

Authors’ contributions

TM conceived the idea, obtained funding, and conducted the data analysis with full access to the dataset and full responsibility of data integrity and analysis. TM and LJ developed the first draft of the paper. JRS and CDL provided important suggestions on study design and statistical analysis. JRS, CDL, and YJX did the literature review and contributed critically to revising the manuscript. All co-authors approved the final manuscript.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/07420528.2023.2170240

Additional information

Funding

This work was supported by the NH-INBRE (New Hampshire – Institutional Development Award (IDeA) Networks of Biomedical Research Excellence), P20GM103506, from the National Institute of General Medical Sciences of the NIH. https://www.nigms.nih.gov/research/drcb/IDeA/Pages/INBRE.aspx.