Clock change raises heart risk
Health experts warn daylight‑saving clock changes can spike heart‑attack risk—Aurelio Rojas cites increases of up to 24%—so scale back high‑intensity sessions immediately after the shift. (ecoticias.com) (marca.com)
A University of Michigan analysis of PCI-treated acute myocardial infarction admissions used the Blue Cross Blue Shield of Michigan Cardiovascular Consortium registry covering March 2010–September 2013 and identified a short‑term shift in timing of presentations concentrated on the Monday after the spring clock change. (openheart.bmj.com) Researchers exploiting Indiana’s staggered history of daylight‑saving practice reported a 27.2% increase in AMI admissions after spring transitions that persisted for roughly two weeks in their dataset. (sciencedirect.com) A large 2025 cross‑sectional analysis of 168,870 patients published in JAMA Network Open found no significant difference in AMI incidence or in‑hospital outcomes during daylight‑saving weeks versus control weeks, with the exception of an anomalous 2020 spring spike. (jamanetwork.com) Systematic reviews and meta‑analyses report mixed evidence: pooled spring‑transition relative risks cluster near 1.04 with substantial heterogeneity across studies, while autumn effects are more consistently null. (di.aerzteblatt.de) Mechanistic reviews link the post‑transition signal to one‑hour sleep loss and circadian misalignment that can raise sympathetic tone and trigger pro‑thrombotic, inflammatory pathways implicated in plaque rupture and thrombosis. (mdpi.com) (uab.edu) The American Heart Association issued guidance in March 2024 urging precaution around the spring shift, and clinicians have advised pragmatic measures such as advancing bedtime by about 15 minutes on the 2–3 nights before the change for vulnerable patients. (newsroom.heart.org) (michiganmedicine.org)
