Saying Goodbye to Daylight Saving Time, and Hello to Better Sleep

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Most people do not welcome the end of Daylight Saving Time. The change brings earlier sunrises, but it also means the sun sets sooner and winter feels closer.

There is, however, one upside: the switch to Eastern Standard Time gives people an extra hour of sleep. Even so, the shift can still throw off the sleep cycle. Compared with the springtime change, though, this transition is usually less disruptive.

"It’s a lot easier going from Daylight Saving Time to Eastern Standard Time because we’re actually pushing back the clock and people can get an extra hour of sleep if they want it," says sleep medicine specialist Dr. Robert Satriale, who sees patients at Temple Health-Chestnut Hill Hospital.

The opposite change in spring, when clocks move forward, tends to be harder on the body. "When you’re suddenly forcing yourself to wake up an hour earlier, your body’s circadian rhythm has not adjusted to that," Satriale says, referring to the body’s internal clock.

That internal alarm is controlled by a structure in the brain called the suprachiasmatic nucleus, he explains. It sits above the point where the optic nerves cross, so morning light helps signal that it is time to wake up. In general, the brain begins to want sleep again about 16 to 17 hours after you first open your eyes.

The body’s "clock" starts sounding when you usually wake up and the light is still dim. As the day goes on and the light grows stronger, alertness rises too. Then, shortly after lunch, usually between 1 and 2 p.m., the light dips and many people feel sleepy in the afternoon. The cycle then picks up again until around 8 p.m., when the drive to sleep returns.

"Wakefulness is not light like a light switch," he says. "It’s sort of like a light on a dimmer. When you wake up in the morning, the light is shining dimly, and it gradually gets brighter and brighter as the day goes on. And that correlates to your level of alertness. You’re not just asleep or awake. There’s lots of transition time that has to occur."

The extra hour of sleep can be helpful in a society that is already short on rest, Satriale says. But the change is not without drawbacks.

Some groups are more vulnerable, including older adults. As people age, they often go to bed earlier, wake earlier, and sleep less overall.

"So, suddenly you’re pushing the clocks back and instead of them waking up at 5 o’clock, they’re waking up at 4 in the morning, and they’re just not happy with it," Satriale says. "And many times, when they try to stay up later, that little alarm clock in their brain is still going to go off at the same time, and they’re going to wake up at the same time. So they have a hard time adjusting to it."

People with psychiatric conditions such as anxiety or depression may also have trouble coping with the time shift, and their mood can worsen, Satriale says.

For those who struggle with the adjustment, there are several possible ways to help.

Exercise is always beneficial for sleep, he says, and working out later in the day does not appear to interfere with falling asleep. "We used to think that exercising later in the evening would impair your body from falling asleep, but that doesn’t appear to be true."

Using a phone, spending time online, or watching TV at night can interfere with the circadian rhythm, Satriale says. "All of these things can interrupt the sleep cycle."

Research also indicates that blue light from screens reduces melatonin, the hormone that helps people feel sleepy and ready for bed. Experts recommend limiting blue-light exposure for at least an hour before bedtime.

Another helpful step is getting natural light after dinner, Satriale says.

One option is a light box or light therapy lamp used after dinner. The light output of these devices is measured in lux, and 30 minutes of exposure to a lamp that delivers 10,000 lux is considered ideal.

Light glasses are another option, delivering up to 10,000 lux through small LED lights built into the frame.

Or there is always a simpler approach.

"Many times, all I’m really prescribing is telling people to go out for a walk after dinner," Satriale says. "Get that light and it will help you sleep a bit later the following morning. Light is the most powerful entrainer in the circadian rhythm."