When it comes to sleeping, you’ve probably heard the common advice: aim to get 6 to 8 hours of sleep every night, and the hours of sleep before midnight are more valuable to the body than those acquired between midnight and rising.
Getting adequate sleep—both in quality and quantity—is essential to feeling well, being mentally sharp, preventing certain illnesses and regulating mood. But does bedtime also play a role in the sleep puzzle? Can you stay up late and still get out of bed well-rested enough to function?
Were sharing everything you need to know about sleep and how to catch the most beneficial Z’s.
Why is sleep important?
“When we sleep, the body goes into recovery mode: restoring, revitalizing and preparing for the next day ahead,” says Noah Siegel, MD, Board Certified Sleep Medicine Physician at Massachusetts Eye and Ear, Harvard Medical School and founder of Sleep Boston. “Sleep allows the brain to consolidate memories—everything from facts and figures to motor skills.” By skimping on sleep, we don’t give the brain a chance to put things together from the day. This, he explains, is why pulling an all-nighter when studying for an exam won’t help you: There’s no time to store those facts in any useful way.
The brain’s glymphatic system (think of it as the housekeeping team) uses sleep time to clean out waste products generated within the brain during the day. Sleepiness is what signals us to rest to give the system a chance to tidy things up and take out the trash. To get to the point where the brain can dispose of this accumulation, we need at least 40 minutes of sleep, which explains why you can (hopefully) rise from even a moderate-length nap feeling more mentally clear.
Can you reset your Circadian rhythm?
Circadian rhythms are the sleep/wakefulness cycles by which the body operates. It’s like an internal 24-hour clock that governs when we “should” be awake and asleep and is primarily connected to our environment. Circadian rhythms are observable in humans, animals, plants and bacteria. While the signaling for each organism differs, they tend to be related to light and the timing of daytime and nighttime in their respective environments. Ideally, we want to be asleep when it’s dark and awake when it’s light.
“Our bodies have been set up to be awake during daylight and rest at dark,” says Bill Fish, Founder of Tuck. “It was less than 150 years ago that electricity was invented, so as a species, we would wake with the sunrise to hunt or tend to the field and then retire at night.” These external cues—light and dark—signal the body to be awake or asleep, and we easily fall into rhythms in response to these.
So, if we’re thinking of natural sunlight, the body is programmed to produce melatonin as the sun sets and stop producing it when dawn breaks to wake us up. However, you can accomplish the same effect with artificial lighting, controlling your environment to mimic the sun’s schedule, thereby putting yourself on a similarly-timed but offset-from-nature rhythm.
How do you create the best sleeping environment?
“Dosing schedules,” as Dr. Siegel explains, involve intentionally exposing oneself to light (e.g. a sun lamp) during the time one needs to be awake and avoiding blue light, screens and other light sources when one needs to be asleep, even if these don’t align with what’s going on outdoors. Blackout curtains and sleep masks are effective ways to make a bright sleep environment extra conducive to rest; UV visors and lights placed throughout your home will help achieve daytime-like conditions if you’re awake during non-daylight hours.
Bill also recommends creating a bedroom environment that is conducive to sleep. “I strongly suggest charging your devices in another room,” he advises, noting that you don’t need to be woken by notifications during rest. “Make the room as dark as you can while still being safe. Find an alarm clock that emits a low light and invest in blackout shades that can block streetlights or even the sun in the morning.”
And if you have trouble staying asleep? Bill suggests a white noise machine.“For less than $30, a white noise machine can mask the sounds outside your sleeping space. Your body needs at least 90 minutes to complete the full range of the sleep cycles, so if you’re woken in the middle of the cycle, your body essentially has to start over.”
Having a comfortable, dark and quiet environment will help keep your sleep schedule on track and your rhythms in order.
Does bedtime matter?
With all of that said, does it matter if you go to bed at 10:00pm and wake before dawn, or can you get the same quality sleep if you hit the hay just before the sun comes up?
As Dr. Siegel puts it, “It matters less when you go to bed than how consistent your bedtime is. As long as you keep a regular schedule, you’re more likely to have good quality and good quantity sleep.” That said, it’s less complicated—and requires fewer gadgets—to start winding down your night as dusk settles and to rise with the sun in the morning.
“You get more deep stages of sleep in the earlier part of your sleep time,” says Dr. Siegel. “REM sleep tends to occur closer to waking time, but that has less to do with what time of day it is and more with how long you’ve been asleep.”
Because your sleep architecture—the depth of the sleep stages, lengths and number of cycles of sleep you experience in a night—can change for the worse if your schedule fluctuates too often, Dr. Siegel stresses that a regular, predictable sleep schedule is the best thing you can do when it comes to sleep hygiene. “An ideal sleep is 7 to 8 hours, consolidated into one block of time, optimally when it’s dark,” he explains. If you need to manufacture that dark to fit your life, go for it. The length of the sleep is more impactful on your wellbeing.
Bill adds, “Bedtime needs vary from person to person. While it is possible for people to work the graveyard shift, we want to aim to be at rest for 7 to 9 hours prior to the sun coming up.”
Your body wants to sleep on a schedule, so maintaining a similar bedtime and a similar waking time throughout your week is important. Sleep in alignment with your body’s internal clock. If you’re just never tired at 11:00pm, you don’t have to force yourself to lay in bed and stare at the ceiling for hours. Go to bed when you’re tired with the goal of having that time be consistent—about an hour earlier or later at most—each night.
“Protect your sleep and form good habits,” Dr. Siegel says, emphasizing the importance of prioritizing good rest.