How To “Reset” Your Internal Clock For Deeper, More Restorative Sleep

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September 20, 2021 — 9:31 AM

During a recent trek off the grid, I swapped my cell phone for a book and bedside lamp for a campfire and was amazed by what it did for my sleep.

I tend to be more of a night owl and thought there was no way I’d be able to adjust to falling asleep at 9 p.m. and waking up at the crack of dawn, as others on the trip were doing. But by night three of sleeping in a tent, all I had to do was look up at the dark, starry sky and a wave of relaxation would wash over me immediately. Eight hours later, I’d wake up without an alarm, with the type of energy that usually only comes with a cup of coffee.

Could shifting the body’s circadian rhythm, or internal clock, be this easy? After returning to the land of cell service, I called up Steven Lockley, Ph.D., a neuroscientist at Brigham & Women’s Hospital and associate professor of medicine at Harvard Medical School, to find out.

We even have research to prove it: A pair of studies out of the University of Colorado–Boulder sent people on a weeklong camping trip during the winter and summer. Participants measured their internal clocks (via saliva samples that showed melatonin levels) before and after the excursion, and sure enough, after a week of sleeping under the stars, these clocks more closely matched the natural cycles of light and dark.

“The system is flexible. It can shift, and it can shift quite quickly,” Lockley tells me. This is important because the way society is set up right now really doesn’t do our clocks any favors. Late-night screen time and days spent in dark rooms separate us from the light-dark cycles of the sun and moon, causing our internal clocks to go a bit haywire. These clocks—housed in the hypothalamus region of the brain—serve as essential timekeepers for the entire body. If they’re irregular and out of sync, you can bet that other important processes are too; from sleep to digestion to immune function.

For this reason, Lockley says we “really need to encourage people to reduce the variability in their circadian clocks. And the way to do that is to keep a very regular light-dark schedule.” Ditching artificial light and heading to the woods is one way to do so. But it’s not the only one. Here, Lockley shares how anyone can regulate their circadian rhythm for the sake of their health, from the comfort of their own home:

Exposing yourself to plenty of light during the day and darkness at night is a huge investment in your health. But in the age of technology and artificial lighting, it’s something you have to be pretty diligent about.

If you spend a lot of time indoors, outfitting your home with the right lighting can set you up for success. Lockley has a smart hack for how to do so. In every room, aim to have two light sources. In the kitchen, it can be overhead lighting and under-cabinet lights. In the bedroom, maybe it’s a larger light and a bedside table lamp.

Designate one light in every room as the “daytime” light. It should be a bright, high-intensity light with a slightly blue hue to mimic daylight. Once sunset rolls around, you can turn that one off and switch on the room’s “nighttime” light. That one should be darker, warmer, and preferably on a dimmer. This setup will better mimic natural lighting patterns, helping you feel more alert during the day and relaxed at night.

You can further train your rhythm by limiting technology use after sunset. Our screens—particularly the ones we hold really close to our faces, like cellphones and laptops—flood our eyes with stimulating blue light, sending the not-so-subtle signal that we should stay awake.

If you need to use these devices, Lockley recommends programming them to emit a dimmer, less intense red light (here’s one free app that makes it easy). But if you can help it, he suggests avoiding them altogether for as long as you can before bed, with the goal being to shut them down two to three hours before shut-eye.

“Your natural melatonin window rises about two hours before sleep starts,” he explains of this time window. “If you see light in that time, it suppresses melatonin and tells the brain that it’s daytime.” If two hours is unrealistic for you, he says smaller increments are helpful too. Thirty minutes of screen-free time before bed is better than none!

Two people who live in the same time zone, the same city, and even the same home can actually run on totally different internal clocks. Thanks to lab studies where lighting is strictly controlled, we now know that circadian clocks exist on a continuum. On average, they can range from running on a 23.5-hour cycle to a 25-hour cycle, and the 1.5-hour gap in between explains why some people are night owls and others are morning birds.

It might not sound like much of a difference, but Lockley explains that for every shift in circadian time, there is a fourfold shift in clock time. This means that someone who has a short circadian cycle could feel six time zones away from someone with a long one—yet be expected to function on the same schedule.

As we get better at measuring individual circadian rhythms, Lockley predicts that social and workplace norms will adjust to become more accepting of people’s natural sleep-wake cycles. Until then, he suggests honoring your unique clock by tailoring your daily schedule to your natural energy levels as much as possible.

Lockley refers to the brain’s circadian rhythm as the almighty “conductor of the orchestra” but notes that it’s not the only internal clock we have. Far from it.

Most organs—from the liver to the kidneys to the pancreas—contain their own biological clocks, too. While we still have a lot to learn about these peripheral clocks, Lockley says that they seem to appreciate a consistent schedule. Eating, exercising, and of course, sleeping at similar times every day can help them tick along without a hitch.