Day 1
Set Your (Internal) Clock
Let's compare humans to some of our fellow companions on this Earth. Giraffes sleep for less than five hours across the twenty-four-hour day, while lions spend an amazing sixteen to twenty hours resting or sleeping over that same period. The albatross, an enormous airplane of a bird that can travel ten thousand miles in a single journey, can achieve REM sleep while in flight. And hippos? They sleep underwater, unconsciously surfacing while sleeping in order to breathe. Even flowers have an internal clock, coded into their cells, that tells them when to open and close. For as many types of organisms as there are out there, there are types of sleep rhythms.
We humans are fairly boring sleepers-most adults need a minimum of seven hours of sleep per night, and we can't even swim while we're doing it. And perhaps more so than hippos and flowers, we struggle with sleep. A big reason? Our natural sleep cycles are out of whack.
Once upon a time, human sleep cycles were yoked more firmly to the natural world-we woke with the morning light and wound down into sleep as the sun disappeared. Then we discovered fire, and everything went downhill from there. Now we have electricity. Technology. Schedules that are not so much governed by the natural world but by the new digital one we've created. We have emails to return, Netflix to watch, passions to pursue. We're no longer hunter-gatherers who wake and sleep with the sun-we have jobs that get us up early and keep us up late. We're awash in artificial light beaming at us from lightbulbs, phones, and laptop screens long after our distant ancestors would have been deep into their sleep cycles. If our natural biological rhythms were allowed to be the boss of us, maybe falling asleep and waking up would be as effortless for us as it is for the flower.
Is the answer to go off the grid, live in the woods, and sleep and wake with the sun again like our ancient ancestors? Maybe! A really creative research study found that participants who went camping in the Colorado wilderness for a weekend and weren't allowed to use artificial lighting at night (no flashlights, headlamps, nothing) showed a 69 percent shift in their biological sleep/wake rhythm compared to those who stayed home. But my guess is that most people-even those who have sleep struggles-are probably not willing to cut ties with the civilized world completely in order to fix them. We need to figure out a way-within this electrical, digital, twenty-four-hour, interconnected, fast-paced modern world-to stabilize and re-sync our sleep drivers so that we can get the kind of deep restorative sleep we still need as humans.
That's why we're going to start this project of fixing your sleep first thing in the morning. When people have trouble sleeping, a lot of attention gets paid to bedtime. But setting yourself up for successful sleep doesn't start at bedtime, or an hour before bedtime, or whenever you start to wind down for the... night. It starts the minute you wake up.
When Do You Wake Up?
Five a.m.? Seven? Noon?
If you're expecting a lecture about the early bird getting the worm, it's not going to come from me. I work with lots of people each year in our sleep clinic at UCSF, working on individualized solutions for their insomnia and other sleep difficulties. And I've rarely told anyone they needed to get up early, or really at any particular time. I don't care what time you wake up. I only care that you wake up at the same time every day.
My youngest son is five years old. I mention that to make clear that I have a natural, unstoppable alarm clock built into my life-even on the laziest of weekends, I couldn't sleep in if I tried. But even if I didn't have this kiddo appearing at my bedside at six o'clock sharp, wanting pancakes and to discuss [insert Marvel Avenger], I still wouldn't try to sleep in on the weekends-not anymore. The luxurious sleepy Sundays of my pre-parenting life are far in the rear-view mirror, and it's because of the data.
If you're like most people (and me, before the science of sleep became my career), you spend your work week running a little short on sleep, then you try to "catch up" on the weekends (or whenever your days off roll around) by tacking on an extra hour or two. This sleep debt that builds up across the week is called "social jet lag." Teenagers are the most striking example of this. There are no teens in my home yet (thank goodness) but I certainly remember being one. Beyond the mood swings and the angst, I remember sleeping in-a lot. Teenagers often experience a shift in their sleep rhythm known as "delayed sleep phase" that increases their biological preference to go to bed later at night and wake up later in the morning. Meanwhile, schools start early-much earlier than teens biologically want to awaken-and it produces sleep debt across the week that compounds into sleeping in on the weekend. "Catching up" on sleep like this makes logical sense: If you're thirsty, drink more water. If you're tired, give your body more sleep. Unfortunately though, for someone struggling with sleep, this strategy often backfires. It not only doesn't work, it can actively work against you.
Your body loves to anticipate your next action or need. It makes insulin in anticipation of a meal, and melatonin in anticipation of sleep. It knows to do these things because of cues in your routine and environment-cues that start the moment you open your eyes, and which accumulate through the day. If your routine is erratic, your body gets confused about what it needs to be doing and how it should be using its resources. No, you don't have to become an automaton doing the same thing every day, eating the same meals, etc.! But figuring out a consistent wake-up time is the number one thing I do with people who come into the sleep clinic. And that's because it's the most powerful regulator of the two natural internal processes that cause sleep.
What Makes Us Sleep?
You have two main "drivers" of sleep: your homeostatic sleep drive and your circadian rhythm. These two natural, internal processes in your body work together (though they are independent) to keep you awake when you need to be awake, and asleep when you need to be asleep. They also need to be in sync for you to get great sleep. When they become dysregulated, you start to run into trouble.
Your homeostatic sleep drive is essentially "pressure" for sleep that builds up the longer you're awake. Picture a balloon. It's flat and empty the moment you open your eyes in the morning. As you go through your day, it gradually begins to inflate, filling up with sleepiness. When it's at this optimal amount-picture a perfectly inflated balloon-you feel the need for sleep. Your eyes get heavy, you climb into bed, and drift off. When you take a nap, you're basically "letting some of the air" out of the balloon, or relieving some of that sleep pressure.
What causes sleep pressure to increase? Well honestly, we aren't 100 percent sure-as much as we've mapped the human brain during sleep, there's still a lot we don't know about sleep even though it's one of the most basic and essential biological processes of the human experience. But one of the leading hypotheses is that our sleep drive is hooked to the buildup of certain neurochemicals-which are byproducts of brain activity. A specific neurochemical responsible for sleepiness is, we think, adenosine. If you've ever taken a science class, you might remember learning about ATP, or adenosine triphosphate, the energy source for all the living cells in our body. While you're awake, adenosine builds up in the brain. As you sleep, that neurochemical drains away. Caffeine, one of the most common ways to keep ourselves awake despite an ever-growing sleep balloon, works because it engages in a biochemical battle with adenosine in the brain. There's basically a fight between the two molecules that breaks out in your brain, and caffe