Daylight Saving and Sleep: Setting Back the Clock Could Sabotage Your Schedule


The thought of gaining an extra hour of sleep at the end of daylight saving time may make you giddy with excitement—but the time switch could also be a trigger for nighttime sleep and daytime alertness problems. Whether you have an existing sleep condition or you've always gotten regular shut-eye, theres a chance you could be hurting once the clock falls back.

"The fundamental problem we have in our current 24/7 society is that everyone is already somewhat sleep deprived," says Patrick J. Strollo Jr., MD, medical director of the University of Pittsburgh's Sleep Disorder Program. "When we make even small adjustments in sleep schedules, that can have a negative impact."

driving-clock-late
The switch to darker daytime hours could lead to drowsy driving.
(GETTY IMAGES/HEALTH)
End of daylight saving sends traffic accidents soaring
Contrary to popular belief, that extra early-morning hour doesn't necessarily mean more sleep. In fact, many people use the time change as an excuse to stay out an hour later that night, says Dr. Strollo; that can translate to trouble when sleepy drivers hit the road later that day. A 2003 study by researchers at Stanford and Johns Hopkins universities analyzed a 21-year period and found a significant spike in traffic accidents on the Sunday that ended daylight saving time.

Even for a few days after the time switch, motorists should exercise extra caution behind the wheel, especially commuters who have worked a long day. Combining dark roads with end-of-day exhaustion and stress is a recipe for disaster, but preventive measures can help. A short nap is the best solution, though it's not realistic in most workplaces. "If you don't have any issues with insomnia, coffee or another caffeinated beverage can also help you with your commute home," says Dr. Strollo.

Drowsy drivers aren't the only ones who should watch out. The sudden loss of daylight in the evenings sends a pedestrian's risk skyrocketing, according to a seven-year study by researchers at Carnegie Mellon University. They found that after daylight saving ended in a typical October, the risk of pedestrian fatalities (per mile walked) jumped 186%, before dropping 21% on average in December. The researchers chalked this up not just to darker roadways, but also to drivers having a difficult time adjusting to the end of daylight saving.

(On the bright side, the fall time change may lower your risk of heart attack—at least temporarily. Swedish scientists recently found that heart attacks dropped the Monday after a time change, possibly because people were getting an extra hour of sleep over the weekend.)

'Tis the season for added fatigue
Sunday's switchover kicks off a cold, dark season, which can leave you lethargic and longing to stay under the covers, even if you've never had sleep problems in the past. Earlier sunsets and long, dark evenings can make fatigue worse, and you may find yourself dragging.

Use the end of daylight saving time to your advantage: If youve been struggling with overscheduled days and sleep deprivation, spend that extra hour in bed this weekend and use it as a chance to catch up. If you have insomnia or are prone to sleep problems, however, any change in your schedule—even an extra hour in bed—might perpetuate restlessness. Stay up an hour later than normal, suggests J. Todd Arnedt, PhD, assistant professor of psychiatry and neurology director of the Sleep Medicine Program at the University of Michigan. "If someone is used to sleeping from11 to 7, one strategy would be for the individual to stay up until 12, set the clock to 11 p.m. when getting into bed, and then get up at 7 a.m. the next day," he says.

Whatever type of sleeper you are, you can use the time change as a starting point for a more consistent schedule. Instead of hitting the snooze button relentlessly next week, drag yourself out of bed in the morning and get moving. "The benefit of the end of daylight saving is that we have more morning light," says Dr. Strollo, and that extra hour of early light can help regulate and strengthen your circadian rhythm. "Light at dawn tends to suppress melatonin, so by getting outside each morning and walking around, you can suppress your sleepiness."


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Lead writer: Kate Stinchfield
Last Updated: October 30, 2008

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