Covassin, Naima

Background Disruption in rest‐activity rhythm (RAR) is an emerging risk factor for cardiovascular disease (CVD) and mortality, but the strength of evidence is unclear. Therefore, we conducted a systematic review and meta‐analysis to assess associations between RAR characteristics and cardiovascular disease incidence or prevalence, cardiovascular mortality, and all‐cause mortality. Methods A systematic search was conducted in PubMed, Web of Science, Cochrane Library, and Embase for cohort or cross‐sectional studies published up to August 2025. The exposure variables were nonparametric RAR parameters, including interdaily stability (describing day‐to‐day stability of the RAR), intradaily variability (a measure of RAR fragmentation), and relative amplitude (indicating robustness or strength of the RAR). The primary outcomes were cardiovascular mortality and all‐cause mortality. The secondary outcomes included cardiovascular disease prevalence and incidence. Results Seven studies involving 109 365 participants were included. Pooled results showed that higher intradaily variability was associated with a significantly increased risk of all‐cause mortality (hazard ratio [HR], 1.05 [95% CI, 1.02–1.09]) and cardiovascular disease prevalence (odds ratio, 1.73 [95% CI, 1.21–2.47]). Lower relative amplitude was significantly associated with higher cardiovascular mortality (HR, 1.50 [95% CI, 1.13–1.98]) and all‐cause mortality (HR, 1.46 [95% CI, 1.27–1.68]). Interdaily stability showed no significant associations with any outcome. Conclusions Measures of disrupted rest‐activity rhythms were associated with increased cardiovascular mortality, and all‐cause mortality. These findings support using RAR metrics as early, noninvasive risk indicators. Future work should investigate whether appropriately timed physical activity and sleep, as well as other interventions targeting RAR can mitigate cardiovascular risk.

Background Sleep fragmentation induced by repetitive arousals is a hallmark of obstructive sleep apnea (OSA). Sleep fragmentation has been linked to hypertension in community‐based studies, but it is unclear if this association is manifest in OSA. We aimed to explore whether frequent arousals from sleep modify the relationship between OSA and prevalent hypertension. Methods and Results A total of 10 102 patients with OSA and 1614 primary snorers were included in the study. Hypertension was defined on either direct blood pressure measures or diagnosis by a physician. Spontaneous, respiratory, and movement arousals were derived by polysomnography. Logistic regression models were used to estimate the associations between arousals and prevalent hypertension in patients with OSA and primary snorers. For every 10‐unit increase of total arousal index, odds of hypertension significantly increased in both the total sample (odds ratio [OR], 1.08; 95% CI, 1.03–1.14; P =0.002) and patients with OSA (OR, 1.10; 95% CI, 1.04–1.16; P <0.001), but not in the primary snoring group. Total arousal index was significantly associated with systolic blood pressure and diastolic blood pressure in the total sample (β=0.05 and β=0.06; P <0.001) and in patients with (β=0.05 and β=0.06; P <0.01), but not in primary snorers. In addition, a greater influence of respiratory events with arousals than respiratory events without arousals on blood pressure in OSA was also noted. Results were independent of confounders, including apnea‐hypopnea index and nocturnal hypoxemia. Conclusions We conclude that repetitive arousals from sleep are independently associated with prevalent hypertension in patients with OSA.