Sleep is a miracle. What else but sleep can mend a broken bone and a broken heart? What else but sleep leads us to a lost memory and to a new idea? What else but sleep can transform the damage done to our bodies, whether by a nice, long run or by trauma, into even greater strength?
Yet moral judgment about sleep is built into the cultural history of the West. Medieval theologians believed humans’ need for sleep was “a divine punishment for the fall of man and a daily reminder to mankind of their sinfulness, weakness and imperfection.”30 America’s puritanical forebears warned (incorrectly) that “immoderate sleep” could cause everything from seizures to infertility to poverty.31 By the 1830s, medical journals were saying that more than four hours of sleep was “an intemperance.”32 Sloth.
The immorality of adequate sleep has changed somewhat over the last fifty years. These days, the message is not so much that we don’t need sleep, but that if a person has time to sleep, they’re doing something wrong; they’re not working hard enough. We’ve made a virtue of being exhausted, of denying ourselves rest. This idea is so embedded in the culture that Emily has lost count of the number of women who tell her they feel guilty about sleeping.
Guilty. About sleeping.
“How come?” Emily asked one group. “You may as well feel guilty about breathing! It’s necessary. So why the guilt over sleep?”
“It’s selfish,” a woman answered. “When you’re asleep, you’re only helping yourself.”
That woman was eighteen years old, and already a committed human giver.
As we’ve seen, sleep is essential not only for your own personal health, but also for your emotional health and relationships, so it’s not even remotely “selfish.” But the lesson here is: Human Giver Syndrome messes with women’s sleep.
So no wonder sleep problems are more common in women than men, especially around menopause.33 As researchers write, women’s sleep is “an ‘invisible workplace’ in which they remain on duty throughout the night, available to provide the physical and emotional support needed to ensure the well-being of their family.” And it’s not limited to the inevitable insomnia-fest that is caring for a newborn, during which, of course, mothers in heterosexual couples are much more likely than fathers to interrupt their sleep to care for a child; this persists through the preschool years, regardless of which partner has a full-time job.34 As human givers, women are expected to sacrifice their sleep for the benefit of others. So we deprive ourselves of a basic physiological need—not a lot, necessarily, but every day, over and over—and the accumulating deprivation wears us down, day by day, until there’s too little left to do all the other things life expects of us.
It’s not just cultural messages that make accessing sleep and rest difficult. Suppose you deal with all your stressors, you check all the boxes on your to-do list, and give yourself permission and opportunity to rest. If you’ve dealt with the stressors but haven’t dealt with the stress itself, your brain won’t let you rest. It will constantly scan for the lion that’s about to come after you, so when you try to go to sleep, your brain won’t let you fall asleep, or it will wake you up over and over, checking for that lion. Complete the cycle, so your brain can transition into rest.
Forty-Two Percent
So how much rest is “adequate”?
Science says: 42 percent.
That’s the percentage of time your body and brain need you to spend resting. It’s about ten hours out of every twenty-four. It doesn’t have to be every day; it can average out over a week or a month or more. But yeah. That much.
“That’s ridiculous! I don’t have that kind of time!” you might protest—and we remind you that we predicted you might feel that way, back at the start of the chapter.
We’re not saying you should take 42 percent of your time to rest; we’re saying if you don’t take the 42 percent, the 42 percent will take you. It will grab you by the face, shove you to the ground, put its foot on your chest, and declare itself the victor.
Have you ever come down with a terrible cold as soon as you finished a huge project? Have you found yourself sleeping twelve or fourteen hours every day for the first three days of vacation? Have you, like Amelia, literally ended up in the hospital after a prolonged period of extreme stress? We’ve established by now that stress is a physiological phenomenon that impacts every system and function in our bodies, including immune functioning, digestive functioning, and hormones. To keep all of those systems in full working order, our biology requires that we spend 42 percent of our lives maintaining the organism of our physical existence.
Here’s what your 42 percent might look like:
? Eight hours of sleep opportunity, give or take an hour.
? Twenty to thirty minutes of “stress-reducing conversation” with your partner or other trusted loved one.
? Thirty minutes of physical activity. Whether with people or alone, you do it with the explicit mindset of gear-switching, Feels-purging, rest-getting freedom. Physical activity counts as “rest” partly because it improves the quality of your sleep and partly because it completes the stress response cycle, transitioning your body out of a stressed state and into a resting state.
? Thirty minutes of paying attention to food. “Thirty minutes?” you say. Don’t fret. That includes all meals, shopping, cooking, and eating, and it doesn’t have to be all at once. It can be with people or alone, but it can’t be while working or driving or watching TV or even listening to a podcast. Pay attention to your food for half an hour a day. This counts as rest partly because it provides necessary nourishment and partly because it’s active rest, a change of pace, apart from the other domains of your life. Think of it as meditation.
? And a thirty-minute wild card, depending on your needs. For some people, this will be extra physical activity, because they need that much to feel good. For others, it will be preparation for their sleep opportunity, because they know their brains need time to transition from the buzzing state of wakefulness into the quiet that allows the brain to sleep. For still others, it will be social play time, because their appetite for social engagement is strong. And for some, it’s simply a buffer for travel and changing clothes and other rest-preparation time (because: reality) during which you engage your default mode network—that is, you let your mind wander.
These are just averages, and as you can see, you’ll sometimes do more than one thing at a time. Some people need more sleep than others—sleep need is estimated to be about 40 percent genetically heritable, so even identical twins can vary a lot.35 Emily needs seven and a half hours, but Amelia needs nine, and if she only gets eight, she really feels it. Natural exercisers may want to spend more time on physical activity. Foodies may want to spend more time on food. Extroverts may want to spend as much of this time as possible with other people. Your mileage may vary; fine-tune it to fit your individual needs.
If you’re thinking, I can get by with less, you’re right. You can “get by,” dragging your increasingly rest-deprived brain and body through your life. And there are periods in your life when adequate rest will not be an option. Newborn baby? No sleep for you. Elderly dog? You’ll be up every four hours. Working three jobs while finishing your degree? Get by on five hours of sleep.
But no one who cares about your well-being will expect you to sustain that way of life for an extended period of time. No one in your Bubble of Love wants you to “get by”; they want you to thrive and grow stronger. We want you to thrive and grow stronger. What makes you stronger is rest.
Suppose you send your ten-year-old child away to camp and you learn they aren’t feeding her adequately because they’re sure she can “get by” on less.