I am not a fan of daylight saving time (DST). I hate springing forward. I’m not alone either. Globally, fewer than 40% of countries still change their clocks, opting instead for a permanent clock time around the year. Of nations that still do change clocks, the practice is overwhelmingly unpopular. According to a 2021 poll by The Associated Press-NORC Center for Public Affairs Research, 75% of Americans would prefer either to have standard time all year long or permanent daylight saving (AP-NORC 2021). A 2018 poll by the European Commission found that 84% of Europeans wanted to get rid of the twice-yearly clock-changing tradition as well (2018).
In terms of the science, the problem with DST seems to lie squarely in the week after the clocks jump forward in March. Springing forward is not only annoying; it is related in an increase in health and safety issues. Research has found that suicide rates and hospital admissions for cardiovascular problems rise in the weeks following the switch to DST (Zhang, Dahlén et al. 2020). Springing forward increases traffic accident risk due to drivers being more fatigued from the transitional loss of sleep and morning light exposure (Carey and Sarma 2017). Some evidence even suggests that the March clock-change may increase overall mortality risk (Poteser and Moshammer 2020). These same trends are not found during the Autumn ritual of “falling back”, or turning the clocks back an hour, and the negative effects of clock-hopping seem to dissipate after the population adjusts to their new time schedule. The take-away is that getting up an hour earlier than usual is bad for your health (and definitely your mood).
While most people are in agreement that we should stop switching the clocks, the real debate is about whether permanent standard time or permanent DST is the better option. Circadian scientists argue that light exposure in the morning is important for entrainment to the light-dark cycle, i.e., good for your health and alertness levels. However, fans of permanent DST argue that more light in the evening increases physical and economic activity, reduces energy costs, and improves road safety. The European Commission has been trying to abandon clock changes since 2018, but can’t decide which direction to choose. Last March, the United States Senate passed legislation to make DST permanent (Congress 2022) but Mexico’s Senate recently voted to stick with standard time (Rubin 2022). Hawaii and Arizona do not observe DST, but parts of Canada are already on permanent DST. The argument boils down to whether you’d rather start your day in darkness or end your day in darkness.
The argument for DST vs. standard glosses over the fact that changing work schedules would negate the difference between either condition. For example, a large percentage of the population still works from home following the COVID-19 pandemic. Individuals who work from home can sleep in later and avoid heavy traffic conditions—a one-two punch for sleep health and safety. Flexible working hours could allow employees to adapt to their own circadian preference for earlier days or later nights. Cutting back on working hours would alleviate the issue as well. Some industries are flirting with the idea of a 4-day work week on the premise that employees can be as productive in a 32-hour period as they can be in a 40-hour period (Veal 2022, Schor, Fan et al. 2023). Cutting back hours to 6 hours per day instead of 4 days per week would allow everyone to come in later and leave earlier, thus avoiding the ill effects of either dark mornings or early nights.
Of course, not everyone can work from home between the hours of 10AM and 4PM. Neither can they work from the office from 9PM-5PM. Shift workers and long-haul transportation professionals are rarely mentioned in the grand scheme of saving daylight. People who work nights or cross time zones repeatedly for work are at an elevated risk for health and alertness problems (Barger, Lockley et al. 2009, Sack 2009, Pallesen, Bjorvatn et al. 2021) that will likely not be ameliorated by either permanent standard time or permanent DST. The reason we have biomathematical modeling systems like SAFTE-FAST is because the interaction between work schedules, time of day, and human performance is too complex to boil down to a one-hour difference. We did recently use SAFTE-FAST to estimate whether permanent DST or permanent standard time would be related to more light exposure or less fatigue compared to the current system in a computational analysis using hypothetical shift work and school schedules. Under controlled hypothetical conditions, there was not a significant difference between the two permanent time options, but they were both related to less fatigue risk relative to the current system of switching the clocks twice a year (Devine 2022).
Springing forward, in my opinion, is the real menace associated with daylight saving. Setting the clocks ahead one hour on March 12th is the same as setting your alarm clock for an hour earlier that day. While we await a permanent solution, you can mitigate your risk by going to bed earlier. Instead of going to bed one hour earlier on March 11th, try going to bed 15 minutes earlier each night leading up to the change (e.g., 10pm on Tuesday; 9:45 on Wednesday; 9:30 on Thursday; 9:15 Friday; 9:00 PM on Saturday). You can also expose yourself to bright light (even artificial light) right after waking up to counteract the absence of sun, and by engaging in alertness-promoting activities like exercise, cold showers, or consuming caffeine before heading off into extra-groggy post-clock-change morning traffic. That is, of course, if you happen to be one of those people who work from an office from 9-5.
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