Sleep Lessons from Our Ancestors
Sleep scientists say our modern lifestyles often work against the natural sleep/wake cycles of our brains—and the past two years have given them a unique opportunity to learn more. Studies showed that during the pandemic, people who could work remotely were often able to adjust their work schedules to more closely match their personal sleep cycles, and many were more productive because of it.
Night owls and early risers. This was especially noticeable among “night owls,” who prefer to go to bed and get up later—and who are often at a disadvantage in the 9 to 5 world. Why are some people morning people and some night owls? Sleep experts point to evolution. In ancient days, people who were night owls would keep an eye on things on their shift, and then the early risers would take over. These different “chronotypes” kept their villages safe. While we modern humans can change our patterns, it’s challenging to overcome our biology.
Wakeful seniors. Evolutionary biologists also offer the “poorly sleeping grandparent hypothesis,” theorizing that older adults are lighter sleepers because this allowed them to be watchful while hunters slept. “Mismatched sleep schedules and restless nights may be an evolutionary leftover from a time many, many years ago, when a lion lurking in the shadows might try to eat you at 2 a.m.,” say sleep experts from University of Nevada Las Vegas. “A lot of older people go to doctors complaining that they wake up early and can’t get back to sleep, but maybe there’s nothing wrong with them. Maybe some of the medical issues we have today could be explained not as disorders, but as a relic of an evolutionary past in which they were beneficial.”
Waking in the night. Before the Industrial Revolution, people didn’t necessarily sleep in a single block of eight hours or so. Virginia Tech professor Roger Ekirch reports that Europeans would go to bed for a few hours as soon as darkness fell—“first sleep,” this was called. Then they might wake up around midnight for a while, perhaps socializing, praying or doing a little work, before “second sleep,” which lasted until dawn. For most of us, there’s no going back to the pre-industrial “first sleep” and “second sleep” pattern. Yet many of us do wake up for a while in the middle of the night. If this is seriously disrupting your sleep, talk to your doctor. But sleep experts say worrying about this wakeful period might keep us awake even longer and nudge us into middle-of-the-night fretting. Instead, they say, try to enjoy a time of quiet rumination before you drift back off to sleep. And if you find yourself lying awake for longer than half an hour, it’s better to get up and do some relaxing activity until you feel sleepy again.
Napping during the day. Even today, people in hot climates might wake up, work for a while, take a siesta during the warmest part of the day, and then work through the cooler twilight hours. Though today some older adults with sleep problems are advised against napping, many of us could benefit from some daytime shuteye. Some companies, including Proctor & Gamble, Google, Nike and NASA, even provide “nap rooms” where employees can take a short power nap.
Night equaled darkness. When the sun went down, ancient humans went to sleep. But artificial lighting has changed all that. Dr. Charles Czeisler of Harvard Medical School explains, “Artificial light exposure between dusk and the time we go to bed at night suppresses release of the sleep-promoting hormone melatonin, enhances alertness and shifts circadian rhythms to a later hour—making it more difficult to fall asleep.” Sleep experts recommend using low-wattage, incandescent lamps as you’re winding down before bedtime. Eliminate light pollution in your sleeping area with light-blocking window coverings or a sleep mask. If your room has a night light for safety, position it so it doesn’t shine into your eyes while you are lying down. That goes for your alarm clock, as well.
Silent night. Nighttime was traditionally a time of quiet, save for the breathing of our fellow humans and the chirping of insects. This may be why many people report that they sleep best when they are camping. Even when we’re asleep, our brains react to sounds, disturbing our sleep slightly even if we don’t wake up. If you can hear street noises, your neighbor’s TV, barking dogs, a snoring partner or birds chirping at dawn, use ear plugs or invest in a white noise machine or app to drown out the sleep-disrupting sounds.
Keeping our cool. Sleep experts tell us a room temperature of around 65° is ideal for restful slumber. This has always been a challenge during hot weather. But even in the dead of winter, our modern homes are often overheated. Set your thermostat lower at night—cool enough that you can sleep under the covers comfortably. Add a room air conditioner or fan in the warm days of summer. Choose a mattress, bedding and sleepwear that don’t trap heat.
Minding our medications. Used properly and under the supervision of a doctor, sleep medications can be of help. But they can disrupt our natural sleep cycle, sometimes severely. Talk to your doctor about the sleep medications you take. And don’t forget to discuss today’s most common sleeping aid: a “nightcap.” Alcohol consumed too close to bedtime can interfere with our natural sleep mechanisms. Today’s spirits are far more potent and readily available than our ancestors’ mead and fermented juices.
Control coffee drinking. Historians tell us coffee drinking swept the world just as the Industrial Revolution forced people into cities and out of their natural sleep and wake cycles. Some say, only partially in jest, that without coffee to wake us up, modern industrial society wouldn’t have succeeded. Coffee is a mostly safe stimulant, and even contains healthful nutrients. But the caffeine in coffee notoriously keeps us awake if we consume it too close to bedtime.
Working out and winding down. Exercise during the day improves the quality of our sleep. Our ancestors worked hard—getting enough exercise was not a problem for them! But today, many modern humans spend most of the day sitting down. Ask your doctor about an exercise program that’s right for you, which includes aerobic and weight-bearing activities. Be sure to allow some down time between exercise and bedtime. Envision our ancestors who, done with their day’s toil, settled in around the fire telling stories. Choose calm, soothing activities like reading or listening to quiet music to help you transition into sleep.
Put away your devices. We don’t have to worry about lions and wolves like our ancestors did—but we have our own sleep disruptors these days. “Light-emitting screens are in heavy use within the pivotal hour before sleep,” reports Dr. Czeisler, who is also chief of the Division of Sleep and Circadian Disorders Department at Brigham and Women’s Hospital. “Invasion of such alerting technologies into the bedroom may contribute to the high proportion of [people] who reported that they routinely get less sleep than they need.” So avoid using your computer or smartphone right before bedtime, turn off devices at night, and if you use an e-reader, choose a model that is not backlit.
Poor sleep weakens our immune system and leads to diabetes, heart disease, even dementia. If you are having trouble sleeping, talk to your doctor. You may be referred for a sleep evaluation to help identify and treat the problem. Practicing good sleep hygiene that supports the body’s natural sleep patterns, as recommended above, is a good first step.
The information in this article is not intended to replace the advice of your health care provider. Talk to your doctor if you have concerns about your sleep.