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Daylight Saving Time
- Daylight saving time (DST) starts on the second Sunday in March and ends on the first Sunday in November.
- The transition into and out of daylight saving time can temporarily disrupt your circadian rhythm, making it harder to fall asleep, wake up, and stay alert.
- Healthy sleep habits, including gradually adjusting your sleep schedule and getting morning light exposure, can help your body adapt more quickly after the clocks change.
The idea behind daylight saving time (DST) is to adjust our clocks by an hour so that there’s more daylight in the evening. In this way, proponents of DST see it as a way to “save” natural light. And while adjusting the time by one hour may not seem like a drastic change, sleep experts have noted troubling trends that occur during the transition between Standard Time and DST, particularly in March.
Furthermore, DST can cause sleep problems by disrupting the body’s internal clock. Abrupt clock changes alter the daily patterns of exposure to natural light, which is the main driver of circadian rhythms. Some people also experience insomnia symptoms around the spring time changes.
Below, we explore how daylight saving time affects sleep, why the spring transition is especially challenging, and what you can do to adjust more easily.
What’s New (July 2026): The U.S. House has passed legislation that would make daylight saving time permanent nationwide. The bill must still pass the Senate and be signed into law before it takes effect. Many sleep medicine organizations, including the American Academy of Sleep Medicine, continue to recommend permanent standard time as the healthier long-term option, as it better aligns with the body’s natural circadian rhythm.
When Is Daylight Saving Time?
Daylight saving time (DST) is the yearly practice of setting clocks forward one hour between the months of March and November. DST is often referred to as “Spring Forward, Fall Backward” because of when these time changes occur.
- When does daylight savings time start? For the start of DST, we set our clocks forward one hour at 2 a.m. on the second Sunday in March, which often results in one less hour of sleep that night. In 2026, that was on Sunday, March 8.
- When does daylight savings time end? At 2 a.m. on the first Sunday in November (in 2026, that’s November 1), we set our clocks back one hour.
How Does Daylight Saving Time Affect Sleep?
Humans and other mammals are guided by circadian rhythms, which are 24-hour cycles that regulate sleep and other key bodily functions such as appetite and mood. These rhythms are largely dependent on light exposure, synchronizing with natural light-darkness cycles to promote healthy, high-quality sleep.
Transitioning twice a year between standard time and daylight saving time changes the hours when we are exposed to natural light. This can interfere with your sleep-wake cycle and may throw off your ability to feel alert in the morning and sleepy at night.
In this way, circadian misalignment can contribute to sleep loss and sleep debt, which refers to the cumulative effect of not getting enough sleep over a period of days or weeks.
Humans are most vulnerable to sleep loss during the spring clock change. One study found that the average person receives 40 minutes less sleepon the Monday after “springing forward.”
In addition to sleep loss, studies have found that people are at greater risk of mood disturbance, suicide, and being involved in traffic accidents around both bi-annual clock changes. That said, daylight saving time may reduce some traffic accidents as more people drive home from work in daylight.
Major sleep disruptions are less likely to occur in November when daylight saving time ends. In fact, for many, this clock change is an opportunity to get an extra hour of sleep from “falling back.” However, some people have difficulty adjusting to a new wake-up time.
For most people, the effects of springing forward or falling back gradually subside over a few days or weeks. But some studies suggest that certain people never fully acclimate to clock changes and daylight saving time. For them, circadian misalignment may become a chronic condition. This can lead to more serious health problems, especially for those who have to cut sleep short because of work or school.
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Should We End Daylight Saving Time Permanently?
Many sleep experts advocate for abandoning the system altogether in favor of single, year-round time. They argue that permanent standard time better suits circadian rhythms and would benefit public health and safety.
On the other side of the argument, people in favor of daylight saving time argue that it decreases energy consumption, reduces car accidents, and facilitates more commerce and after-work activity. They also cite evidence that crime rates decrease when daylight saving time is in effect.
For now, federal law prohibits the adoption of permanent daylight saving time in the United States. States can use permanent standard time, but only a few states, including Hawaii and Arizona, actually do so.
In recent years, legislation has been introduced in Congress to authorize states to adopt permanent daylight saving time. But these bills have stalled, and there are no indications that federal legislative change is imminent.
Many state legislatures have passed laws that would observe permanent daylight saving time contingent upon a change in federal laws. In this way, clock changes continue to be a matter of debate at the state level, but unless federal regulations change, the effect of state action is limited.
Sleep Tips for Daylight Saving Time
In the days and weeks leading up to clock changes, various tips can help limit negative impacts on your sleep.
- Avoid alcohol before bed: While drinking alcohol can cause sleepiness, it leads to sleep disruptions and lowers sleep quality.
- Establish a consistent sleep routine: Going to bed and waking up at the same time each day – including the weekends – can promote more consistent sleep before and after changes between standard time and daylight saving time.
- Gradually alter your bedtime: Two to three daysbefore the transition to DST in early March, it may help to wake up 15 to 20 minutes earlier than usual. Adjusting your sleep schedule in advance may help you have a smoother transition to DST.
- Spend time outdoors: Since natural light is a driving force behind our circadian rhythms, exposure to sunlight can alleviate feelings of tiredness in the morning. Natural light can also help reorient your circadian rhythm to minimize sleep disruptions.
- Nap in moderation: If you feel sleepy, a short nap may give you a boost of energy. These naps should last for 20 minutes or less to avoid waking up groggy.
- Don’t consume caffeine too close to bedtime: Caffeine consumed in the afternoon can throw off your sleep. To prevent problems, be mindful of when and how much caffeine you consume.
Frequently Asked Questions
When does daylight saving time end permanently?
As of now, daylight saving time has not been made permanent in the United States. In July 2026, the U.S. House of Representatives passed a bill that would make daylight saving time permanent, but the legislation must also pass the Senate and be signed by the president before it can take effect.
When did daylight saving time start?
Daylight saving time was first adopted in the United States in 1918 during World War I as a way to conserve fuel by making better use of daylight. Although it was repealed after the war, daylight saving time returned during World War II and was later standardized nationwide with the Uniform Time Act of 1966, which established the schedule followed by most states today.
Why do we have daylight saving time?
Daylight saving time was created to shift an hour of daylight from the morning to the evening during the warmer months of the year. Supporters say it encourages outdoor activities, reduces energy use, and benefits businesses by providing more evening daylight. However, many sleep experts argue that the twice-yearly clock changes disrupt circadian rhythms and sleep, and some advocate for adopting permanent standard time instead of permanent daylight saving time.
What states don’t have daylight saving time?
Hawaii, certain areas of Arizona, and the U.S. territories of American Samoa, Guam, the Northern Mariana Islands, and the U.S. Virgin Islands do not implement DST. But the rest of of the United States has officially observed DST since 1966.
Who created daylight saving time?
No single person invented daylight saving time. Benjamin Franklin famously suggested shifting schedules to make better use of daylight in a satirical 1784 essay, but he did not propose changing clocks. More than a century later, New Zealand entomologist George Hudson and British builder William Willett independently promoted the idea of moving clocks forward during the summer. Their proposals helped inspire the modern daylight saving time systems that many countries use today.
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Eric Suni has over a decade of experience as a science writer and was previously an information specialist for the National Cancer Institute.
Dustin Cotliar, MD, holds a medical degree from the State University of NY (SUNY) Downstate College of Medicine, and a master’s in public health from Columbia University, where he focused on healthcare policy and management. He is board-certified in Emergency Medicine, with over eight years of practice that includes emergency medicine, urgent care, and telemedicine.
Learn more about our medical advisory boardReferences7 Sources
American Academy of Sleep Medicine (AASM). (2014, March 3). Saving daylight, losing sleep: Insomnia Awareness Day is March 10. American Academy of Sleep Medicine – Association for Sleep Clinicians and Researchers.
https://aasm.org/saving-daylight-losing-sleep-insomnia-awareness-day-is-march-10/Rishi, M. A., Cheng, J. Y., Strang, et al. (2024). Permanent standard time is the optimal choice for health and safety: an American Academy of Sleep Medicine position statement. Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine, 20(1), 121–125.
https://pubmed.ncbi.nlm.nih.gov/37904574/Barnes, C. M., & Wagner, D. T. (2009). Changing to daylight saving time cuts into sleep and increases workplace injuries. The Journal of applied psychology, 94(5), 1305–1317.
http://doi.apa.org/getdoi.cfm?doi=10.1037/a0015320Doleac, J. L., & Sanders, N. (2015, December 8). Under the Cover of Darkness: How Ambient Light Influences Criminal Activity.
https://www.mitpressjournals.org/doi/abs/10.1162/REST_a_00547American Academy of Sleep Medicine. (2016, March 3). Health Advisory: Daylight Saving Time [Press release].
https://aasm.org/resources/pdf/pressroom/daylight-saving-time-sleep-health-advisory.pdfNational Conference of State Legislatures. (2025, March 4). Daylight saving time: State legislation.
https://www.ncsl.org/transportation/daylight-saving-time-state-legislationBryner, J. (2025, March 3). Daylight saving time 2025: When does the time change, and why? Live Science.
https://www.livescience.com/56048-daylight-saving-time-guide.html
