Good news awaits: you’ll gain a glorious extra hour of sleep. The downside: it will be dark as a pocket by late afternoon across the U.S. for the next few months. Daylight saving time ends at 2 a.m. local time next Sunday, Nov. 3, so don’t forget to set your clocks back an hour before bed. Standard time continues until March 9, when we “spring forward” again with the return of daylight saving time.
This spring time shift can be rough on your body. Darker mornings and lighter evenings can throw your internal clock into disarray, making it challenging to fall asleep on time for weeks or longer. Studies even show a spike in heart attacks and strokes following the March time change.
“Fall back” is typically easier. However, it might still take some time to adjust your sleep habits. The additional challenge of leaving work in the dark or finding enough daylight to exercise remains. Those with seasonal affective disorder, a form of depression linked to shorter days and reduced sunlight in fall and winter, may also find this period tough.
Several health groups, including the American Medical Association and the American Academy of Sleep Medicine, argue it’s time to do away with time changes. They advocate for sticking with standard time, which better aligns with the sun and human biology.
Most countries do not observe daylight saving time. Those that do, mainly in Europe and North America, vary in the dates they adjust their clocks.
A couple of U.S. states – Arizona and Hawaii – do not change their clocks and remain on standard time year-round.
Our brains contain a master clock influenced by exposure to light and darkness. This circadian rhythm, roughly a 24-hour cycle, dictates when we become sleepy and when we are alert. The rhythm changes with age, explaining why early-rising children turn into hard-to-wake teens. Morning light resets this rhythm, while evening darkness triggers the release of melatonin, inducing drowsiness. The extra evening light from daylight saving time delays this melatonin surge, disrupting the circadian cycle.
Moreover, this circadian clock affects more than just sleep, influencing heart rate, blood pressure, stress hormones, and metabolism. Even a one-hour change can throw off sleep schedules, as work and school start times remain unchanged. This is problematic, considering many people are already sleep-deprived. About one in three U.S. adults sleep less than the recommended seven-plus hours nightly, and more than half of U.S. teens don’t get the recommended eight-plus hours on weeknights. Sleep deprivation is linked to heart disease, cognitive decline, obesity, and numerous other health issues.
To prepare for the time change, some suggest adjusting bedtimes gradually in the days leading up to it. Increasing exposure to sunlight can help reset your circadian rhythm for healthier sleep.
Lawmakers occasionally propose eliminating the time change altogether. The most notable recent attempt, the now-stalled bipartisan Sunshine Protection Act, aimed to make daylight saving time permanent. Health experts argue the opposite should happen; they believe standard time should be permanent.