UF Researcher: Don't Lose Sleep Worrying About Daylight-Saving Time

March 30, 1999

GAINESVILLE — Dreading the thought of trying to stay awake at work Monday morning after setting your clocks ahead this weekend? Don’t lose sleep over it.

One of the most frequent questions UF psychologist Wilse Webb is asked as a sleep researcher — whether the change to daylight-saving time causes much sleep-loss drowsiness — gives him a big yawn and evokes little sympathy.

“My usual answer is that I can’t conceive of it making any difference at all because it’s a shift of only one hour once a year,” said Webb, a UF emeritus professor in psychology and international sleep expert. “When people say they can’t handle the change, that it knocks them for a whack, they’re deluding themselves. Sleep is a very gentle tyrant.”

Webb, author of the book “Sleep: The Gentle Tyrant,” said most people go to bed at different times anyway, so their total hours of sleep vary from night to night.

In one study he did on college students, only 3 percent went to bed within a half hour of the time they did the night before. Even though students’ schedules are highly irregular, the findings are not out of line for the general population, he said.

“In most of the United States, people go to bed when they want to and get up when they have to,” he said. “And when they want to is not the same time every night.”

Because people lose sleep on weekdays anyway, an additional hour is not going to matter, Webb said. Research shows that nearly everyone extends their sleep by about an hour on weekends, a reaction to not getting enough sleep during the week, he said.

It takes more than a loss of an hour’s sleep to cause a craving for an extra cup of coffee, Webb said. And over time, lack of sleep affects only one part of mental functioning, the ability to sustain one’s attention during routine tasks, he said.

“I never worry about surgeons or people landing airplanes because they are obviously paying attention,” he said.

But jobs that involve monitoring instruments or conditions that change only once in a while, such as operating a nuclear power plant or driving a car, are much riskier because of the tendency for a sleepless person’s attention to wander without the challenge of constant stimulation, Webb said. For that reason, long haul-truck driving, known for its back-to-back shifts, is the most dangerous occupation in the world.

Even if people think losing an hour’s sleep to daylight-saving time is going to fog their brains, there really is nothing they can do, Webb advises. Trying to catch up on sleep ahead of time by going to bed early is futile.

Because of some unknown evolutionary function, the human biological clock is actually set for a day lasting roughly 25½ hours instead of 24 hours, Webb said. As a result, people find it much simpler to prolong a day than shorten it, he said.

“It’s exceedingly easy to go to bed an hour later, but for reasons we can’t possibly figure out, it’s almost impossible to get to bed an hour earlier,” he said. “My advice is don’t try. Go to bed at the usual time.”