The upside: You’ll enjoy an extra hour of sleep. The downside: The sun will set early for the next several months in the U.S.
Daylight saving time ends at 2 a.m. local time next Sunday, Nov. 3. This means you should set your clock back an hour before bed. Standard time will remain in effect until March 9, when we’ll once again “spring forward” with the return of daylight saving time.
The transition to standard time is usually easier on the body. However, it might still take some time to adjust your sleep habits. Additionally, leaving work in the dark or exercising while there’s still light may be challenging. Some individuals with seasonal affective disorder (SAD), a type of depression linked to shorter days and less sunlight during fall and winter, may also experience difficulties.
Several health organizations, including the American Medical Association and American Academy of Sleep Medicine, have advocated for eliminating time switches. They argue that sticking with standard time aligns better with the sun and human biology.
do not observe daylight saving time. For those who do — mainly in Europe and North America — the date for switching clocks varies.
Two states — Arizona and Hawaii — don’t change and stay on standard time.
Here’s what to know about the twice-yearly time change ritual.
How the body reacts to light
The brain has a master clock that’s set by exposure to sunlight and darkness. This circadian rhythm is a roughly 24-hour cycle that regulates when we feel sleepy and when we’re more alert. These patterns change with age, explaining why early-rising children often become hard-to-wake teenagers.
Morning light resets the rhythm. As evening approaches, levels of a hormone called melatonin begin to rise, inducing drowsiness. Excessive light in the evening — like the extra hour from daylight saving time — delays this surge, causing the cycle to become out of sync.
This circadian clock influences more than just sleep. It also affects factors like heart rate, blood pressure, stress hormones, and metabolism.
How do time changes affect sleep?
Even a one-hour shift in the clock can disrupt sleep schedules — especially since work and school start times remain constant.
This is concerning because many people are already sleep-deprived. Roughly 1 in 3 U.S. adults sleep less than the recommended seven-plus hours nightly, and over half of U.S. teenagers 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.
How to prepare for the time change
Some people try to prepare for a time change jolt by gradually adjusting their bedtime in the days leading up to the change. There are strategies to ease the adjustment, including getting more sunshine to help reset your circadian rhythm for healthy sleep.
Will the U.S. ever get rid of the time change?
Lawmakers occasionally propose eliminating the time change altogether. The most prominent recent attempt, a now-stalled bipartisan bill called the Sunshine Protection Act, proposes making daylight saving time permanent. However, health experts argue that standard time should be made permanent instead.