Daylight saving time (DST) is a biannual event that affects millions of people around the world. The transition from daylight saving time back to standard time in the fall may seem like a small adjustment—gaining an extra hour of sleep sounds like a welcomed change—but in reality, this shift can have significant effects on both physical and mental health. The “fall back” change impacts our sleep cycles, cognitive functioning, and general well-being. While many are aware of the difficulties associated with the spring transition, the fall shift has its own set of challenges.
In this article, we’ll explore what daylight saving time is, its origins, the health impacts of the shift back to standard time, and practical strategies to prepare your body and mind for the change.
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What is Daylight Saving Time?
Daylight saving time is the practice of moving the clocks forward by one hour in the spring to make better use of daylight during the evenings, and then turning the clocks back by one hour in the fall to return to standard time. The main goal is to conserve energy and make better use of natural daylight. However, research shows that the energy-saving benefits may be minimal, and the disruptions to circadian rhythms—the internal body clock that regulates sleep—can lead to a variety of health issues.
When Does Daylight Saving Time End?
Daylight saving time in 2024 ends on Sunday, November 3, at 2 a.m. local time. When the clocks “fall back,” most people will gain an extra hour of sleep, but the darker evenings and earlier sunrises may throw off the body’s natural rhythm. This switch back to standard time can take days, or even weeks, for the body to fully adjust.
When Does Daylight Saving Time Begin AgDain?
In 2025, daylight saving time will begin again on Sunday, March 9. At that point, the clocks will move forward, and people will lose an hour of sleep while gaining an extra hour of daylight in the evening. Both transitions—spring and fall—have distinct effects on health, although the “spring forward” is often associated with more acute negative outcomes like sleep deprivation and increased accidents.
The History of Daylight Saving Time
Daylight saving time has been around for more than a century. It was first introduced in the United States in 1918, primarily as a wartime measure to conserve energy during World War I. The belief was that by making better use of daylight hours, less electricity would be needed for lighting homes and businesses. Despite these intentions, several studies in modern times have suggested that the actual energy savings are marginal.
Contrary to popular belief, daylight saving time was not introduced to benefit farmers. In fact, agricultural groups were some of the strongest opponents of the practice. Farmers argued that the biannual clock changes interfered with their schedules, particularly during harvesting seasons. After initial resistance, the Uniform Time Act of 1966 created a standardized system for daylight saving time across the country, although states were allowed to opt out.
States and Territories that Don’t Participate in Daylight Saving Time
While most U.S. states observe daylight saving time, there are a few exceptions. Hawaii, Arizona (except for the Navajo Nation), and several U.S. territories, including Puerto Rico, Guam, and the U.S. Virgin Islands, have chosen to remain on standard time year-round. These states and territories cited various reasons, such as geographic location and minimal energy savings, for opting out of the practice.
Health Impacts of the End of Daylight Saving Time
Many assume that the “fall back” shift, which provides an extra hour of sleep, is easier on the body than the “spring forward” shift. However, the transition back to standard time still carries a variety of health risks and challenges. Below, we explore several ways the time change can impact your physical and mental health.
Disruption to Sleep Patterns
Even though we gain an extra hour of sleep when we fall back, this shift can still disrupt normal sleep patterns. According to Shelby Harris, a psychologist and director of sleep health at Sleepopolis, an extra hour of sleep can lead to early awakenings or difficulties falling asleep at night. Disruptions to sleep cycles, particularly for those who already struggle with sleep disorders or insomnia, can affect overall sleep quality and daytime functioning.
Increased Stroke Risk
Research has shown that both the spring and fall transitions of daylight saving time are associated with an increased risk of stroke. A Finnish study in 2016 found that there was a higher incidence of ischemic strokes—caused by blood clots—shortly after the time change. The body’s circadian rhythms, which are responsible for regulating many essential functions including sleep, blood pressure, and metabolism, are thrown off by the shift, potentially leading to cardiovascular issues.
Higher Rates of Depression
The end of daylight saving time also correlates with an increase in depression, particularly in the days following the shift back to standard time. A Danish study from 2016 found a rise in depression diagnoses in the immediate aftermath of the time change. This is likely due to the sudden reduction in daylight hours, as shorter days and longer nights can contribute to the onset of Seasonal Affective Disorder (SAD). SAD is a form of depression triggered by changes in daylight exposure and is estimated to affect about 5% of the U.S. population.
Increased Car Accidents
Driving in darker conditions can also be hazardous. After the clocks shift back and the sun sets earlier in the afternoon, there is an uptick in car accidents due to reduced visibility during the evening commute. The earlier onset of darkness can also contribute to fatigue and inattentiveness behind the wheel, making it more dangerous to drive during these times.
How to Prepare for the Time Change
While the health impacts of the end of daylight saving time may sound alarming, there are steps you can take to minimize the disruption to your routine and well-being. Here are some tips from experts to help you adjust to the time change and support your physical and mental health during the transition.
Gradually Adjust Your Sleep Schedule
One of the best ways to ease into the time change is to gradually adjust your sleep and wake times. Natalie D. Dautovich, an assistant professor at Virginia Commonwealth University and environmental scholar at the National Sleep Foundation, suggests shifting your bedtime and wake-up time by 15 minutes each day leading up to the time change. This will allow your body to acclimate slowly, reducing the shock of losing or gaining an hour.
Establish a Bedtime Routine
Creating a consistent and calming bedtime routine can help signal to your body that it’s time to wind down. A bedtime ritual could include putting away electronic devices, which emit blue light and interfere with the production of melatonin, the hormone that regulates sleep. Judy Ho, a licensed clinical and forensic neuropsychologist, recommends avoiding heavy meals, caffeine, alcohol, and intense exercise close to bedtime. Instead, engage in relaxing activities such as reading, meditation, or light stretching to prepare your body for sleep.
Increase Exposure to Natural Light
Exposure to natural light is crucial for regulating your circadian rhythms. Jamie Zeitzer, a professor of psychiatry and behavioral sciences at Stanford University, advises getting plenty of sunlight, especially in the morning, to help your body adjust to the new time. Sunlight in the morning helps reset the body’s internal clock and can improve mood and alertness. If natural sunlight is limited during the fall and winter months, consider using light therapy or sun lamps, which can help alleviate symptoms of depression and support sleep quality.
Stick to a Consistent Sleep Schedule
After the clocks have shifted, it’s important to maintain a consistent sleep schedule. Go to bed and wake up at the same time every day, even on weekends. This will help reinforce your body’s circadian rhythm and promote better sleep. Avoid napping during the day, as this can interfere with your ability to fall asleep at night.
