Daylight Saving Time Research Articles

Short-term vascular responses to spring and fall daylight savings time shifts.

Daylight saving time (DST) is a Western biannual time transition, setting the clock back 1 h in the fall and forward 1 h in the spring. There is an epidemiological link between DST and acute myocardial infarction risk in the first week following the spring shift; however, the mechanisms underlying the effect of DST on cardiovascular function remain unclear. The purpose of this study was to explore the short-term cardiovascular changes induced by fall and spring shifts in DST in a convenience sample of healthy adults. We hypothesized that spring, but not fall, DST shifts would acutely increase central pulse wave velocity, the gold standard measurement of central arterial stiffness. Twenty-one individuals (fall: n = 10; spring: n = 11) participated in four visits, occurring 1 wk before and at +1, +3, and +5 days after spring and fall time transitions. Central, brachial, and radial pulse wave velocity as well as carotid augmentation index were assessed with applanation tonometry. Sleep quality and memory function were assessed via questionnaire and the Mnemonic Similarities Task, respectively. Neither fall or spring transition resulted in changes to cardiovascular variables (carotid-femoral pulse wave velocity, carotid-brachial pulse wave velocity, carotid-radial pulse wave velocity, heart rate, mean arterial pressure, or augmentation index), sleep quality, or cognitive function (all P > 0.05). Our findings do not provide evidence that DST shifts influence cardiovascular outcomes in healthy adults. This study emphasizes the need for further research to determine the mechanisms of increased cardiovascular disease risk with DST that help explain epidemiological trends.NEW & NOTEWORTHY The debate of whether to abolish daylight savings time (DST) is, in part, motivated by the population-level increase in all-cause mortality and incidence of cardiovascular events following DST; however, there is an absence of data to support a physiological basis for risk. We found no changes in pulse wave velocity or augmentation index during the subacute window of DST. Large multisite trials are necessary to address the small, but meaningful, effects brought on by a societal event.

The practice of Daylight Saving Time in Canada: Its suitability with respect to sleep and circadian rhythms.

Daylight Saving Time (DST) is the practice of setting the clocks one hour forward from Standard Time (ST) in the spring and back again to ST in the fall. This commentary discusses the impact of bi-annual time changes on sleep and circadian rhythms and suggests avenues to minimize negative outcomes on the well-being of Canadian citizens. Ideally, ST should be close to solar time, meaning that daylight is equally distributed before and after noon time, i.e., when the sun is at its highest point in the sky. In Canada, some provinces are proposing to opt out of DST to either return to constant ST throughout the year or to implement permanent DST. National and international associations of clinicians and researchers on sleep and biological rhythms and in health sciences have positioned themselves in favour of permanent ST. In Canada, the Canadian Sleep Society and the Canadian Society for Chronobiology have also issued such a position. This commentary focuses on the implications of previous research findings for sleep and health in Canada given its northern geographical location. It concludes with a research agenda focusing on the Canadian context.

Cambio de horario y riesgo cardiovascular

The impact of light on our society is significant, influencing our central nervous system through natural light’s role in regulating circadian rhythms. Daylight Saving Time (DST) is often justified for energy savings, particularly in residential lighting. The central nervous system’s master biological clock, located in the hypothalamus, synchronizes peripheral clocks, including those in the cardiovascular system. Desynchronization between endogenous circadian systems and environmental cycles increases cardiovascular risk. The springtime DST change exacerbates social jet lag, leading to sleep debt, sympathetic activation, and increased proinflammatory cytokines. Studies show a temporary increase in myocardial infarction rates in the week following the springtime shift. From a health perspective, there’s growing evidence of negative effects on human metabolism and physiology due to changes in lighting schedules.

Efectos del cambio al horario de verano en la salud mental de los adolescentes: una revisión

The transition to Daylight Saving Time (DST) has been associated in the general population with various negative health effects, such as an increased risk of cardiovascular and cerebrovascular problems, along with symptoms of mental health issues. These effects are directly attributed to the sleep phase delay and, consequently, the deficit of sleep hours resulting from the measure. There is les evidence regarding the effect of DST on the child and adolescent population, although it is known that in these age groups, chronic sleep deprivation and disruption of chronobiological cycles play a role in the onset and course of various disorders, such as mood disorders, anxiety disorders, and neurodevelopmental disorders. The present work aims to review the existing evidence on the potential repercussions of DST on mental health in the adolescent population. First, a general model is presented regarding risk and protective factors for chronobiological cycles in adolescence. Subsequently, results from specific studies in adolescents are presented, covering both mental health and academic performance areas. Finally, the implications of these results are discussed.

The Annual Rhythms in Sleep, Sedentary Behavior, and Physical Activity of Australian Adults: A Prospective Cohort Study.

Sleep, sedentary behavior, and physical activity have fundamental impacts on health and well-being. Little is known about how these behaviors vary across the year. To investigate how movement-related behaviors change across days of the week and seasons, and describe movement patterns across a full year and around specific temporal events. This cohort study included 368 adults (mean age = 40.2 years [SD = 5.9]) who wore Fitbit activity trackers for 12 months to collect minute-by-minute data on sleep, sedentary behavior, light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA). Data were analyzed descriptively, as well as through multilevel mixed-effects linear regression to explore associations with specific temporal cycles (day-of-the-week, season) and events. Movement patterns varied significantly by day-of-the-week and season, as well as during annual events like Christmas-New Year and daylight saving time (DST) transitions. For example, sleep was longer on weekends (+32 min/day), during autumn and winter relative to summer (+4 and +11 min/day), and over Christmas-New Year (+24 min/day). Sedentary behavior was longer on weekdays, during winter, after Christmas-New Year, and after DST ended (+45, +7, +12, and +8 min/day, respectively). LPA was shorter in autumn, winter, and during and after Christmas-New Year (-6, -15, -17, and -31 min/day, respectively). Finally, there was less MVPA on weekdays and during winter (-5 min/day and -2 min/day, respectively). Across the year, there were notable variations in movement behaviors. Identifying high-risk periods for unfavorable behavior changes may inform time-targeted interventions and health messaging.

The Effects of Daylight Saving Time Adjustments on Investor Information Processing

ABSTRACT Although daylight saving time (DST) is thought to provide economic benefits, extant research documents various adverse effects of DST adjustments. However, prior research provides little conclusive evidence about the effects of DST adjustments on capital market participants. We examine the effects of “spring forward” DST advances, which disrupt the human sleep cycle and economic activities, on investors’ processing of earnings news. We find a delayed price response to earnings news released during the first week following a DST advance. We also find that this effect is stronger among firms with investors who are more likely to be trading on earnings news and among firms with less sophisticated investors. Our findings contribute to research on the unintended consequences of DST adjustments and to the growing literature on intra-investor variation in disclosure processing costs. Our study may be of interest to legislators currently debating proposed legislation that would eliminate DST phasing. Data Availability: Data are available from the sources cited in the text. JEL Classifications: D83; G14; M41; M48.

Let me sleep on it: sleep and investor reactions to earnings surprises

We explore if sleep deprivation affects how investors react to relevant news. Using the transition to Daylight Saving Time (DST) in spring as a disruption to sleeping patterns, we show that investors underreact to a firm’s earnings surprise in the days after the transition to DST. Further, an earnings surprise in the days after the transition to DST is associated with a positive drift in the post-announcement period. Our findings are consistent with sleep-deprived investors mispricing and subsequently revisiting relevant information. Overall, our results highlight the importance of investors’ cognitive ability for efficient market pricing.

Automation and optimization in daylight analysis and life cycle assessment for automated daylight monitoring device for a metro rail station box in Ahmedabad, India

Daylight analysis and optimization are pre-requisites for energy-efficient and sustainable infrastructure. Conventional practices of designing and providing artificial lighting often ignore the consideration of the availability of natural daylight for the infrastructure. This paper aims to analyze the availability and potential of natural daylight reviewing the sky component type at a designated location, real-time sensor-based illuminance measurement on-site and BIM-based daylight simulation. Consequently, a sensor prototype was deployed to the metro rail station for automated optimization. Firstly, the sky component type of Ahmedabad was determined based on the literature review. Subsequently, sensors were integrated at the strategic grid point location covering the entire metro rail station to collect real-time Illuminance for daylight factor calculation. Furthermore, BIM-based sun path and shadow analysis and daylight simulation were carried out to suggest the possibility and potential of daylight savings. Finally, based on all the analysis and results, a newly designed sensor-based prototype was developed and equipped to enhance automated optimization for daylight savings, which resulted in 29% energy savings monthly. This approach significantly helps the project stakeholders to enhance building energy performance and lead a step closer towards sustainable infrastructure.

The welfare effects of time reallocation: evidence from Daylight Saving Time

AbstractDaylight Saving Time (DST) is a widely adopted practice implemented by over 70 countries to align sunlight with day‐to‐day activities and reduce energy demands. However, we do not have a clear knowledge of how it affects individuals' welfare. Using a regression discontinuity combined with a difference‐in‐differences design, we find that the Spring DST transition causes a significant decline in life satisfaction. By inducing a reallocation of time, the transition into DST deteriorates sleep quality and increases time stress, which in turn affects physical and emotional health. Using an event study approach, we find that such effects persist for about six days after the DST transition. Conversely, we provide evidence that the Autumn DST transition gives rise to a significant increase in life satisfaction. Finally, using a simple cost‐benefit analysis, we discuss the potential benefits of ending DST.

Daylight Saving Time Practice and the Rate of Adverse Cardiovascular Events in the United States: A Probabilistic Assessment in a Large Nationwide Study

We investigated the association of daylight saving time (DST) transitions with the rates of adverse cardiovascular events in a large, US-based nationwide study. The study cohort included 36,116,951 unique individuals from deidentified administrative claims data of the OptumLabs Data Warehouse. There were 74,722 total adverse cardiovascular events during DST transition and the control weeks (2 weeks before and after) in spring and autumn of 2015-2019. We used Bayesian hierarchical Poisson regression models to estimate event rate ratios representing the ratio of composite adverse cardiovascular event rates between DST transition and control weeks. There was an average increase of 3% (95% uncertainty interval, −3% to −10%) and 4% (95% uncertainty interval, −2% to −12%) in adverse cardiovascular event rates during Monday and Friday of the spring DST transition, respectively. The probability of this being associated with a moderate-to-large increase in the event rates (estimate event rate ratio, >1.10) was estimated to be less than 6% for Monday and Friday, and less than 1% for the remaining days. During autumn DST transition, the probability of any decrease in adverse cardiovascular event rates was estimated to be less than 46% and a moderate-to-large decrease in the event rates to be less than 4% across all days. Results were similar when adjusted by age. In conclusion, spring DST transition had a suggestive association with a minor increase in adverse cardiovascular event rates but with a very low estimated probability to be of clinical importance. Our findings suggest that DST transitions are unlikely to meaningfully impact the rate of cardiovascular events.

Increase in seizure activity is associated with change to daylight savings time as identified by an implanted thalamic neurostimulator in bilateral thalamic centrum medianum nuclei

Increase in seizure activity is associated with change to daylight savings time as identified by an implanted thalamic neurostimulator in bilateral thalamic centrum medianum nuclei

Eeny, meeny, miny, moe-Summer time and out are you? The working population in the EU would likely benefit from elimination of daylight saving time.

Daylight (saving) time (DST) is an over one century old practice to maximize the overlap between natural day light and individual active time (i.e., non-sleep time). Whether to abandon the practice is subject to an ongoing, twice ayear intensifying debate. Arequest to abandon the practice is based on the lack of benefits in terms of energy savings and potential negative health effects. We present atool that captures one key aspect of importance to the circadian system: maximizing the overlap of natural day light with human active time, focusing on early morning light exposure as the primary stimulus for our circadian system. Based on publicly available data we incorporated an approximation of the 27European Union (EU) countries' spatial population distribution into acalculation of average exposure to morning sunlight under DST or no DST conditions for each EU27 country and the entire region. An online app offers visualization of these differences on the country level alongside apopulation-weighted average for the EU27. Our findings support that the majority of the EU's working population would likely benefit from the elimination of daylight saving time if maximizing an adequate morning stimulus is the primary goal and adjusting actual time zones or biennially changing the clock is not an option.

The Alarm Clock Against the Sun: Trends in Google Trends Search Activity Across the Transitions to and from Daylight Saving Time

The human circadian timing system depends on the light/dark cycle as its main cue to synchronize with the environment, and thus with solar time. However, human activities depend also on social time, i.e. the set of time conventions and restrictions dictated by society, including Daylight Saving Time (DST), which adds an hour to any degree of desynchrony between social and solar time. Here, we used Google Trends as a data source to analyze diurnal variation, if any, and the daily peak in the relative search volume of 26 Google search queries in relation to the transitions to/from DST in Italy from 2015 to 2020. Our search queries of interest fell into three categories: sleep/health-related, medication and random non sleep/health-related. After initial rhythm and phase analysis, 11 words were selected to compare the average phase of the 15 days before and after the transition to/from DST. We observed an average phase advance after the transition to DST, and a phase delay after the transition to civil time, ranging from 25 to 60 minutes. Advances or delays shorter than 60 minutes, which were primarily observed in the sleep/health-related category, may suggest that search timing for these queries is at least partially driven by the endogenous circadian rhythm. Finally, a significant trend in phase anticipation over the years was observed for virtually all words. This is most likely related to an increase in age, and thus in earlier chronotypes, amongst Google users.

Abstract 13688: Association Between Daylight Saving Time and Acute Myocardial Infarction in Canada

Background: Recent studies have suggested an increased risk of AMI following daylight saving time (DST) transitions in cohorts of American and European patients. We aim to validate this finding in a Canadian population. Methods: We performed a retrospective cohort study of patients admitted to the Hôpital du Sacré-Coeur de Montréal, with a diagnosis of AMI requiring a PCI. Patients aged ≥18 years hospitalized between 2018 and 2022 were included. The primary endpoint was the incidence of AMI two weeks following DST transitions. The secondary endpoint was infarct size by biomarker assessment and LVEF. Results: 1142 charts were reviewed with 775 patients meeting the inclusion criteria (244 in the study group and 531 in the control group). Baseline clinical characteristics were comparable between both groups. (Table 1) The rate of AMI per day following DST transitions was 1.74 compared to 1.90 during control periods. DST was not associated with an increase in AMI (IRR = 0.92, 95% CI 0.79 - 1.07, p = 0.295). (Table 2) During the spring shift, the IRR was 0.83, p = 0.106, and during the autumn shift, the IRR was 1.01, p = 0.933. The rate of AMI was higher on the first day following DST, but it did not reach statistical significance (rate of AMI per day = 2.00; IRR = 1.05; p = 0.845). The transition to DST was not associated with a larger infarct size by CK-MB assessment, but LVEF was significantly slightly higher following DST transitions (LVEF 50 ± 11 % vs 48 ± 10 %, p = 0.038). Conclusion: In this cohort of Canadian patients, there was no significant association between DST transitions and the incidence of AMI. LVEF was higher following DST transitions, but infarct size was similar between study and control groups.

Abstract 12827: Daylight Savings Time Practice and the Rate of Adverse Cardiovascular Events in the United States: A Probabilistic Assessment in a Large Nationwide Study

Introduction: Previous studies have shown inconsistent changes in the rates of adverse cardiovascular events after daylight savings time (DST) transitions. In this large-scale, U.S.-based nationwide study, we sought to investigate the association of DST transitions with the rates of adverse cardiovascular events. Methods: The study cohort included 36,116,951 unique individuals from de-identified administrative claims data of the OptumLabs Data Warehouse®. There were 74,722 total adverse cardiovascular events during the week of DST transition and the control weeks (two weeks prior and after) in spring and autumn of 2015-2019. We used Bayesian hierarchical Poisson regression models to estimate the event rate ratios (ERR) representing the ratio of composite adverse cardiovascular event rates (acute myocardial infarction, stroke, cardiogenic shock, cardiac arrest, and sudden death) between DST transition weeks and control weeks. Results: Our results showed an average increase of 3% [95% uncertainty interval; -3% to 10%] and 4% [-2% to 12%] in the rate of adverse cardiovascular events during Monday and Friday of the spring DST transition week, respectively. The probability of spring DST transition being associated with a moderate-to-large increase in the event rates (ERR>1.10) was estimated to be <6% for Monday and Friday, and <1% for the remaining days. During autumn DST transition, the probability of any decrease in adverse cardiovascular event rates was estimated to be <46% and a moderate-to-large decrease in the event rates to be <4% across all days of the week. Conclusions: Spring DST transition week had a suggestive association with a minor increase in adverse cardiovascular event rates on Monday and Friday. The probability of this association to be of clinically meaningful magnitude was estimated to be very low. We did not observe any evidence suggestive of a change in adverse cardiovascular event rates immediately following autumn DST transition. Taken together, our findings, based on a large, diverse cohort from across the United States, suggest that DST transitions are unlikely to significantly impact the rate of cardiovascular events.

Should the Daylight Saving Time be abolished? Evidence from work accidents in Italy

Should the Daylight Saving Time be abolished? Evidence from work accidents in Italy

User behaviour in public squares after dark

This research concerns the influence of electric lighting on user behaviour in public squares and whether differences in people’s use of the square can be observed between daylight and darkness. Previous research on pedestrians suggests that lighting can support human needs for reassurance, accessibility, comfort and pleasure. While these findings are also likely to be applicable to the use of public squares, there is little empirical evidence to verify that. A field study was conducted to explore user behaviour in two differently illuminated public squares. Observations of the movements and stationary activities of people in the squares were recorded at both squares for the same times of day in the weeks before and after the daylight savings clock change, enabling a comparison of activity in daylight and after dark. 5296 observations were recorded and lighting conditions were captured with HDR-photography and aerial photos. Kirseberg square, with asymmetric luminaires and metal halide lamps, revealed a decrease in stationary activity after dark. Lindeborg square, with omnidirectional luminaires and high-pressure sodium lamps, revealed an increase in stationary activity. In conclusion, the patterns of user behaviour in the two public squares after dark seem to be differently influenced by electric lighting, pointing to a need for further understanding of users’ experience of the squares after dark.

Driving fatigue increases after the Spring transition to Daylight Saving Time in young male drivers: A pilot study

The Spring transition to Daylight Saving Time (DST) has been associated with several health and road safety issues. Previous literature has focused primarily on the analysis of historical crash and hospitalization data, without investigating specific crash contributing factors, such as driving fatigue. The present study aims to uncover the effects of DST-related circadian desynchrony and sleep deprivation on driving fatigue, by means of a driving simulator experiment.Eighteen participants (all males, age range 21–30 years, mean = 24.2, SD = 2.9) completed two 50-minute trials (at one week distance, same time and same day of the week) on a monotonous highway environment, the second one taking place in the week after the Spring transition to DST. Driving fatigue was evaluated by analysing several different variables (including driving-based, physiological and subjective indices) and by comparison with a historical cohort of pertinent, matched controls who had also undergone two trials, but in the absence of any time change in between.Results showed a considerable rise in fatigue levels throughout the driving task in both trials, but with significantly poorer performance in the post-DST trial, documented by a worsening in vehicle lateral control and an increase in eyelid closure. However, participants seemed unable to perceive this decrease in their alertness, which most likely prevented them from implementing fatigue-coping strategies. These findings indicate that DST has a detrimental effect on driving fatigue in young male drivers in the week after the Spring transition, and provide valuable insights into the complex relationship between DST and road safety.

Daylight saving all year round? Evidence from a national experiment

We study the effects of staying on daylight saving time (DST) permanently on electricity consumption, generation, and emissions. In October 2016, Turkey chose to stay on DST all year round. Employing alternative identification methods, we find a negligible overall impact on consumption. However, the policy has a strong intra-day distributional effect, increasing consumption in the early morning and reducing it in the late afternoon. This change in the load shape reduced generation by dirtier fossil fuel plants and increased it by cleaner renewable sources that can more easily satisfy peak load generation. Emissions from generation decreased as a result. A large presence of hydropower, which is a reliable provider of energy to the grid in peak times, was crucial to achieve this reduction.

The Effect of Daylight-Saving Time on Percutaneous Coronary Intervention Outcomes in Acute Coronary Syndrome Patients-Data from the Polish National Registry of Percutaneous Coronary Interventions (ORPKI) in the Years 2014-2022.

Many factors related to the switch to summer/winter time interfere with biological rhythms. This study aimed to analyze the impact of time change on clinical outcomes of patients with acute coronary syndromes (ACS) undergoing percutaneous coronary intervention (PCI). Electronic data of 874,031 patients with ACS who underwent invasive procedures were collected from the Polish National Register of Interventional Cardiology Procedures (ORPKI) between 2014 and 2021. We determined the number of patients undergoing PCI and periprocedural mortality during the day of spring or autumn time change and within the first 3 and 7 days after the time change. We demonstrated the impact of time changes on the periprocedural mortality of ACS patients within 1 day and the period of 3 and 7 days from the time change. We observed that the occurrence of all ACS and NSTEMI on the first day was lower for both time changes and higher in the case of UA and spring time change. The autumn time change significantly reduced the occurrence of all types of ACS. A significant decrease in the number of invasive procedures was found after autumn transition in the period from the first day to 7 days for ACS, NSTEMI, and UA. The occurrence of ACS and the number of invasive procedures were lower for both changes over time. Autumn time change is associated with increased periprocedural mortality in ACS and a less frequent occurrence of UA and NSTEMI within 7 days.