Daylight saving time is just around the corner! Millions of Americans will be changing their clocks back an hour at 2 a.m. this Sunday morning. This annual ritual comes with the popular side effect of earning you an extra hour of sleep. It triggers a cascade of physiological changes within your body, most notably impacting your circadian rhythm.
The circadian rhythm is a natural, roughly 24-hour cycle that helps determine sleepiness and alertness levels throughout the day. This internal clock—to use the scientific term, it’s a circadian clock—is shaped by external cues, particularly the light-dark cycle. When clocks fall back, the shift can disrupt this finely tuned system, especially in the first few days following the change.
Getting exposure to morning sunlight helps to reset your body’s circadian rhythm, which is essential for regular healthy sleep cycles. Getting exposure to natural light in the morning helps increase your alertness levels during the day. It helps your body produce melatonin in the evening too. Melatonin, the hormone that controls the body’s sleep-wake cycle, spikes in the evening, inducing sleepiness.
Insomnia experts advise transitioning into standard time by going to bed a little earlier each night. Try shifting your bedtime by a mere 15 minutes per night leading up to the clock change. This step-by-step transition allows communities to address unintended consequences of the move before the change is fully implemented.
Despite the benefits of an extra hour of sleep, statistics reveal that many American adults struggle to meet their sleep needs. About one in three U.S. adults do not get the recommended seven or more hours of sleep per night. Over three-quarters of U.S. teenagers do not get the recommended eight or more hours of sleep on school nights. This sleep deprivation can compound the difficulty of adjusting to changes that daylight saving time brings.
The effects of this time change can go far beyond just feeling tired. According to research, car crashes spike in the days after the daylight saving time switch. Heart attacks spike as well during this time. With millions of Americans facing such grave statistics, we need to find better and more scalable ways to cope with the transition.
While most states participate in daylight saving time, Arizona and Hawaii remain on standard time year-round, avoiding these seasonal disruptions altogether. Falling back in the fall means an hour more sleep, experts remind us. Once spring does come and we spring forward an hour, it generally makes losing that sleep much more difficult.
Jamie Zeitzer, a researcher in circadian biology, draws attention to the consequences of disrupted circadian rhythms. These disruptions have a very unique impact on each person. He puts it this way, Imagine the central clock…as the conductor of an orchestra. Each organ plays like a unique instrument unto itself in this musical orchestra. This metaphor underscores the importance of synchronization—doing the right thing at the right place and time—for our nation’s health.
To combat this, Zeitzer stresses the need for a regular sleep routine. He dives into how those irregular patterns throw off our body’s natural circadian rhythms and make us less effective at functioning.
In fact, circadian patterns are typically disrupted with age. That’s what makes our youngest children and oldest adults largely at risk to the havoc time changes can wreak. For those affected by seasonal affective disorder, time changes can be particularly difficult to manage. Their sensitivity to changes in light exposure makes this process especially difficult to overcome.
