Key result
Higher circadian relative amplitude is linked to ~9% lower CVD risk per SD.
Why the study?
Disrupted sleep–wake organisation may contribute to CVD, but prospective evidence using objective, wearable-derived circadian rhythmicity measures beyond total physical activity volume and sleep duration remains limited.
Does higher wearable-derived sleep–wake circadian organisation (relative amplitude) reduce incident cardiovascular disease in adults without prevalent CVD?
Cohort (n=89,253)
Does higher wearable-derived sleep–wake circadian organisation (relative amplitude) reduce incident cardiovascular disease in adults without prevalent CVD?
Wearable-derived sleep–wake circadian organisation (relative amplitude) is independently associated with incident cardiovascular disease beyond total physical activity volume and sleep duration, and mitigates the excess risk associated with physical inactivity.
Background Disrupted sleep–wake organisation is a behavioural marker of circadian dysregulation and may contribute to cardiovascular disease (CVD). Prospective evidence using objective, wearable-derived circadian rhythmicity measures beyond total physical activity (PA) volume and sleep duration remains limited. Methods We analysed 89,253 UK Biobank participants without prevalent CVD who provided valid 7-day wrist-worn accelerometer data (2013–2015). Sleep–wake circadian organisation was quantified using relative amplitude (RA), derived non-parametrically from the contrast between the most active 10-h (M10) and least active 5-h (L5) periods. Incident CVD was ascertained via linked hospital and mortality records. Cox models estimated hazard ratios (HRs) adjusting for sociodemographic factors, lifestyle factors, cardiometabolic risk factors, self-reported sleep duration, and accelerometer-derived total PA volume. Results Over a median follow-up of 9.6 years, 5,793 incident CVD events occurred. Higher RA was associated with lower CVD risk after full adjustment (per 1-SD higher RA: HR 0.91, 95% CI 0.89–0.94). Participants in the lowest versus highest RA quartile had a 29% higher CVD risk (HR 1.29, 95% CI 1.17–1.42). RA modified excess risk associated with low PA volume (inactive) (P-interaction=0.028): inactive individuals with high RA (robust rhythm) showed no elevated risk compared with the high-PA/high-RA group (HR 1.00, 95% CI 0.91–1.09). Associations were stronger in adults aged ≥60 years (P-interaction<0.001). Conclusions Wearable-derived sleep–wake circadian organisation (RA) was associated with incident CVD beyond total activity volume and sleep duration. More robust 24-h behavioural organisation may help identify higher- versus lower-risk individuals within low-activity adults and may complement activity-based prevention strategies, particularly in older adults.Figure 1.Sleep–wake RA and incident CVDFigure 2.Joint RA–PA and incident CVD
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Zhao et al. (2026) conducted a cohort in Incident cardiovascular disease (n=89,253). Sleep–wake circadian organisation (relative amplitude, RA) vs. Per 1-SD higher RA (or lowest vs highest RA quartile) was evaluated on Incident cardiovascular disease (HR 0.91, 95% CI 0.89–0.94). Higher sleep–wake circadian relative amplitude was associated with lower incident CVD risk (HR 0.91 per 1-SD; 95% CI 0.89–0.94).
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