The Sleep Prescription summary

If you’ve ever had a bad night’s sleep, you know how jumpy and anxious it can make you feel the next day. Sleep and stress are deeply intertwined in a couple of ways. First, our body’s stress response can affect our sleep quality. However, you might be surprised to learn that this isn’t always a huge issue.

When it comes to everyday stressors – like family, work, or finances – we’re fairly resilient. Our bodies are actually very good at managing stress, so much so that daytime stress isn’t always a good predictor of sleep quality. In other words, you can have a very stressful day and still get a good night’s sleep.

It's 3 p.m., you're sitting at your desk, and you feel your energy starting to wane. You wonder: did I not get enough sleep last night, or is my blood sugar just low? To power through the rest of your day, you reach for a third cup of coffee. Sound familiar?

This mid-afternoon period of low energy is actually perfectly normal. It’s a natural part of the circadian rhythm we learned about on day one. While everyone’s rhythms vary slightly, we all tend to follow a similar pattern.

As humans, we’re complex creatures. What sets us apart from other mammals is our capacity for imagination. This is a pretty great thing – and the root of most of our success as a species. However, our capacity for imagination also comes with downsides, namely anxiety, worry, and rumination.

Throughout our busy days, it’s much easier to quickly move past anxious thoughts than to confront them. However, as soon as we lie down in bed, these worries come back to haunt us. This process of rumination, where we replay past events in our minds, is considered one of the major causes of insomnia.

When we start to drift off to sleep, it feels pretty gradual, right? Actually, at a neurological level, it’s more like flipping a switch. The body’s production of melatonin is one of the main drivers of this process. 

Remember how we talked about darkness as a cue for melatonin production? This is actually where we tend to run into problems. Unlike our ancestors, our sleep cycles don’t rely on the rising and setting of the sun anymore. We’re bathed in artificial light right up until we crawl into bed.

These days, our lives are largely shaped by things that are out of our control. Our routines are based on work, school, and other scheduled obligations. Throughout all of this, our brains are constantly taking in information, responding to stimuli, and anticipating our needs.

When it comes to sleep, one of the biggest triggers is our beds. Your bed can be an incredibly powerful cue to let your body know that it’s time for sleep. However, it can also work in the opposite way.

The stimulus control that we learned about on day six works in two ways. First, it helps train your body to associate your bed with feelings of sleepiness. Second, it helps rev up your homeostatic sleep drive – a kind of “pressure” that builds up the longer you’re awake. 

You might find it useful to envision this process as inflating a balloon. As soon as you wake up in the morning, the balloon starts to inflate, as sleep pressure gradually builds up. When the balloon is full – hopefully at bedtime – you feel the urge to sleep.