Most of us sleep the same way. Collapse into bed in the late evening, then spend the next 8 hours -- if we're lucky -- dreaming and snoring until the alarm rings. But that's not how everyone does it. Some folks break up their slumber into two or more shifts. It's called segmented sleep, and there's a lot of buzz that it's the way to go in today's fast-paced world.
But before you dive in and make plans for some middle-of-the night chores, think carefully about whether it's really suited to your lifestyle. And watch out for warning signs that this alternate sleep schedule is putting you in a funk.
How It All Got Started
Segmented sleep sounds trendy, but it's not a new idea. In pre-industrial times (and before electricity) it was normal to get up for a couple of hours in the middle of the night, according to historian Roger Ekirch, author of At Day's Close: Night in Times Past. People spent the free time praying, smoking, having sex, or even visiting their neighbors, then went back to sleep until morning.
We may be hardwired to sleep in two periods. A study by the National Institute of Mental Health looked at how people slept when they got 10 hours of light a day -- about as much as on a winter's day. Researchers found that those folks got their shut-eye in two chunks, with a few hours awake in between. That's closer to how animals sleep, too.
Some people follow that split schedule today -- using the middle-of-the-night awake period as a creative time to think, read, meditate, or work.
"There are people for whom that seems to be a productive way to live and suits them just fine," says Mary Carskadon, PhD, a sleep researcher at Brown University. "But it's hard to do if you have family and a job you have to go to every day."
Sleeping in 2 Shifts
Valerie Robin, then a graduate student in Atlanta, tried segmented sleeping for a few weeks in 2014 after reading about its history. She went to bed when it got dark, then got up in the middle of the night to read, write in her journal, or talk on the phone with friends in other time zones. She woke up on her own once the sun came up.
"I was calm," Robin says. "All day long and even at night. I had read that it was like a natural meditative state in the nighttime, but I was like that in the daytime, too."
Although she felt rested and even had extra energy, Robin got tired of missing evening parties and dates and went back to a more conventional schedule. "If everybody slept this way, I'd prefer to sleep this way," she says.
Is It Healthy?
There are mixed views on whether segmented sleeping is safe. Since there hasn't been much research on the effect sleeping in shifts can have on your health, it's best to avoid it unless there's a reason you need to sleep that way, says Clete Kushida, MD, PhD, the medical director of the Stanford Sleep Medicine Center.
"There are so many unknowns," he says. "[Is it] safe in the long term? How does it vary from individual to individual? How does age factor in, or medical conditions, or sleep disorders?"
But Carskadon says she doesn't know of evidence that sleeping in two rounds at night causes health problems, so it's OK if you naturally sleep that way. "I don't think they should worry if they otherwise feel healthy and happy and fulfilled," she says.
One thing to keep in mind if you try segmented sleeping. Artificial light in the middle of the night could have an impact on your circadian rhythms -- the internal clock that controls processes in your body.
So keep light dim at night, Carskadon suggests. And if you can, stay away from light that looks blue -- like LED bulbs -- since it has the biggest effect on circadian rhythms.
Cutting Back on Total Sleep
Some people divide their sleep into a schedule of naps around the clock, sometimes called polyphasic sleeping. It's often designed to let you get by on less total rest.
That's a bad idea, Kushida says, since adults need at least 7 hours of sleep in 24 hours. There can be major consequences if you cut back, he says. When you're sleep deprived, it can:
- Change your metabolism
- Raise hormones that make you eat more and gain weight
- Affect your learning and memory
- Raise your risk of accidents
And it won't help you get more done, either. "You might be doing more harm than good thinking your performance will improve," Kushida says.
Warning Signs
If you want to try an alternative sleeping schedule, pay attention to how you're feeling. Watch out for signals that it's not working. You don't want to put yourself and others at risk because you're short on sleep and try to stay awake when your body says it's time to get shut-eye, Carskadon says.
Look out for these signs of trouble:
- Struggle to focus
- Have a short temper
- Take risks you wouldn't otherwise take
- Feel extremely sleepy
- Fall asleep at the wrong time, like in class or while driving
