Does daylight saving time harm health?

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1. 1

   Daylight saving time, circadian rhythms, and cardiovascular health

   Internal and Emergency Medicine (Manfredini et al.)Published Jul 3, 2018Checked Oct 3, 2026

   “Very recently, the European Parliament, called to decide on possible abolition of the Daylight Saving Time (DST), approved a resolution calling the scientific community to conduct a more in-depth evaluation. The question is based on disruption of body's circadian rhythms. We review here the relationship between DST and cardiovascular health. The available evidence suggests the existence of an association between DST and a modest increase of occurrence of acute myocardial infarction, especially in the first week after the spring shift. Possible mechanisms include sleep deprivation, circadian misalignment and environmental conditions. The role of gender and individual preference in circadian rhythms (chronotype) will need further assessment.”

2. 2

   Daylight Saving Time and Health: Scoping Review with ☸SAIMSARA

   SAIMSARA Journal (SAIMSARA)Published Oct 28, 2025Checked Oct 3, 2026

   “The clearest recurrent findings include a roughly 3% increase in daily total mortality after the spring transition, a 6.25% rise in suicide rates after the spring shift, a 16% increase in deer-vehicle collisions after the autumn transition, and a median 37-minute sleep reduction among patients with delayed sleep-wake phase disorder during daylight saving time. Across topics, the pattern supports circadian misalignment and sleep loss as plausible shared mechanisms linking clock changes to cardiovascular, mental health, occupational, and traffic-related harms, while also showing that some outcomes remain null or inconsistent. These findings support practical planning by clinicians, emergency services, and policymakers around transition periods and are broadly aligned with calls to reduce biannual clock changes in favor of schedules better matched to human biology. Future research should prioritize standardized, high-validity longitudinal and quasi-experimental comparisons of seasonal clock policies, especially to distinguish the acute effects of transitions from the chronic effects of prolonged daylight saving time exposure.”

3. 3

   A systematic review of epidemiological studies into daylight-saving time & health identifying beneficial & adverse effects

   European Journal of Epidemiology (Steponenaite et al.)Published Feb 21, 2026Checked Oct 3, 2026

   “DST-Offset transitions appear associated with decreased all-cause mortality and workplace accidents, but also with increased crimes involving physical harm. Living with DST (compared to Standard Time) appears associated with decreased all-cause mortality and traffic accidents in summer. Standard Time appears is potentially associated with decreased sleep duration during winter. No clear and consistent effects on psychiatric outcomes are identified. Limited studies prevent clear conclusions being drawn regarding other sleep parameters or circadian rhythms. This review indicates that transitions and living with DST (as opposed to Standard Time) during summer months are not uniformly detrimental; however, the evidence base remains limited and heterogeneous. Rather than advocating for maintaining or removing transitions, our synthesis supports a balanced approach. We recommend recognising both adverse and beneficial patterns and prioritising strategies to mitigate risks while awaiting more robust evidence.Registration https://doi.org/10.17605/OSF.IO/R4W6M.”

4. 4

   Acute effects of daylight saving time clock changes on mental and physical health in England: population based retrospective cohort study.

   BMJ (Clinical research ed.) (de et al.)Published Dec 17, 2025Checked Oct 4, 2026

   “n spring), compared mean event rates per day in the week after the clock changes and the control period (four weeks before the changes and weeks 2-4 after).ResultsIn the week after the autumn clock change, five health conditions had fewer events: anxiety (from 17.3 events per day (per year, per region) to 16.7; incidence rate ratio 0.97, 95% confidence interval 0.95 to 0.98), acute cardiovascular disease (from 50.0 to 48.9; 0.98, 0.96 to 0.999), depression (from 44.6 to 42.7; 0.96, 0.95 to 0.97), psychiatric conditions (from 3.5 to 3.3; 0.94, 0.90 to 0.98), and sleep disorders (from 5.4 to 4.9; 0.92, 0.87 to 0.97). Little evidence was found of reductions in eating disorder diagnoses, road traffic injuries, or self-harm or of changes after the spring clock change.ConclusionThe week after the autumn clock change was associated with a reduction in events for cardiovascular disease, sleep disorders, and mental health disorders, but little evidence suggested that the spring clock change was associated with a change in the number of health events. Electronic health records contain the date that a health event is recorded by a clinician, which is not necessarily the date of symptom onset.”

5. 5

   Are there lingering effects of Daylight-Saving Time on sleep and health estimates of an Australian population?

   Sleep advances : a journal of the Sleep Research Society (Kemp et al.)Published Mar 6, 2026Checked Oct 4, 2026

   “A retrospective, cross-sectional design was used to compare subjective data of two nationwide surveys of the Australian population; one population-representative sample, and a convenience sample of those with chronic Insomnia. Respondents were categorized based on whether they were from a DST state or permanent Standard Time (ST) state. We then compared sleep behavior and tendencies in sleep health between DST and ST states. Overall, both samples consistently demonstrated that those from DST states tended to go to bed later and, particularly, rise at later clock times than those from ST states. Importantly, despite a delay in the timing of sleep we found no differences in reported Total Sleep Time nor Sleep Onset Latency; and no sign of impairment on any related health estimates. Very few sleep health variables reached significance (p less impaired than their ST counterparts. We have found no evidence of impairment associated with DST well-into the DST period. Future studies should measure sleep and associated daytime functioning longitudinally and objectively to accurately assess the possible duration of any potential acute DST effect.”

6. 6

   Implications of Sleep Health Policy: Daylight Saving and School Start Times

   CONTINUUM Lifelong Learning in Neurology (Johnson & Malow)Published Aug 1, 2023Checked Oct 3, 2026

   “ABSTRACT: Two proposed public policies, ending seasonal clock change with a transition to permanent Standard Time and moving middle school and high school start times later, are population-based initiatives to improve sleep health. Daylight Saving Time and early school start times are associated with reduced sleep duration and increased circadian misalignment, the effects of which impact not only long-term health outcomes including obesity, cerebrovascular and cardiovascular disease, and cancer, but also mental health, academics, workforce productivity, and safety outcomes. This article highlights studies that led to the endorsement of these public policies by multiple scientific and medical organizations. Neurologists should advocate at the state and federal levels and educate the population about the importance of sleep health.”

7. 7

   When the Clock Shifts: A Comprehensive Review of Daylight-Saving Time (DST), Circadian Disruption, and Neuropsychological Risk in Chronic Mental Illness.

   Brain sciences (Blank et al.)Published May 14, 2026Checked Oct 3, 2026

   “Empirical, theoretical, and mechanistic studies were included to ensure comprehensive synthesis. Across conditions, DST, particularly spring forward transitions, is associated with increased sleep disturbance, impaired executive functioning, reduced attention and working memory, heightened emotional reactivity, increased depressive symptoms, elevated risk of manic episodes, and short-term increases in suicidality. Neurobiological mechanisms include altered melatonin secretion, cortisol dysregulation, Hypothalamus Pituitary Axis (HPA-axis) activation, and clock-gene desynchrony. DST may function as a modifiable negative environmental influence capable of affecting neuropsychological functioning in vulnerable populations. These findings underscore the need for clinical awareness, preventive strategies, and policy reconsiderations, including calls to eliminate seasonal time changes. Standardizing DST-related research outcomes and expanding longitudinal, multi-site studies will be essential for advancing this emerging field.”

8. 8

   Measurable health effects associated with the daylight saving time shift

   PLoS Computational Biology (Zhang et al.)Published Jun 8, 2020Checked Oct 3, 2026

   “We found four prominent, elevated risk clusters, including cardiovascular diseases (such as heart attacks), injuries, mental and behavioral disorders, and immune-related diseases such as noninfective enteritis and colitis to be significantly associated with DST shifts in the United States and Sweden. While the majority of disease risk elevations are modest (a few percent), a considerable number of diseases exhibit an approximately ten percent relative risk increase. We estimate that each spring DST shift is associated with negative health effects-with 150,000 incidences in the US, and 880,000 globally. We also identify for the first time a collection of diseases with relative risks that appear to decrease immediately after the spring DST shift, enriched with infections and immune system-related maladies. These diseases' decreasing relative risks might be driven by the documented boosting effect of a short-term stress (such as that experienced around the spring DST shift) on the immune system.”

9. 9

   Social media analysis reflects the negative sentiments experienced at both time changes with somewhat more depressive impact in early fall.

   PloS one (Ellman et al.)Published Mar 4, 2026Checked Oct 4, 2026

   “We compare sentiment-a measure of individuals overall mood or emotions towards an event-in cities on either side of US time zones the day before and after the societal time change. We find negative shocks to sentiment following both time changes. This effect seems stronger in the fall. Given the amount of daylight relative to a fixed work schedule should be the same in each group of cities on these days, these differences suggest strong negative ceteris paribus reactions to societal time changes, which may indicate preference to abolish these adjustments, although we do not measure preference for DST versus ST. We also use regression analysis to estimate how sentiment changes over time. We find persistent negative impacts from the change to Standard Time in the fall. In contrast, individuals experience a noisy shock to sentiment that attenuates over time. These findings provide evidence that individuals have a more negative reaction to the societal time change to Standard Time in the fall than they do to DST in the Spring. This work highlights the potential that the reaction to societal time changes varies depending on whether moving to or away from DST or Standard Time.”

10. 10

    Daylight saving time (Wikipedia)

    WikipediaPublished Oct 1, 2026Checked Oct 3, 2026

    “Daylight saving time (DST), also referred to as daylight savings time, daylight time (United States and Canada), or summer time (United Kingdom, European Union, and others), is the practice of advancing clocks to (in theory) make better use of the longer daylight available during summer by having darkness fall at a later clock time. The typical implementation of DST is to adjust clocks ahead of standard time by one hour in spring or late winter, and to set clocks back by one hour in the autumn (or fall in North American English, hence the mnemonic: "spring forward and fall back"). In many countries, the part of the year when DST is observed is much longer than the part aligned to standard time. The practice of DST was first tested and widely adopted in the early 20th century, since which many countries have abandoned DST partially or entirely.”