How to set up your bedroom for a great night’s sleep (Turn It Into a Cave)


As I explained in last week’s post, a great night’s sleep starts with 90 minutes of deep sleep. It can increase productivity by up to 150% and prevent acute stress from turning into chronic stress. Now, your bedroom can make or break your deep sleep.

What to do

Turn your bedroom into a cave — by making it dark, quiet and cool.

Why it works

Getting a good night’s sleep starts with 90 minutes of deep sleep. According to Prof. Matthew Walker (pictured above), deep sleep “[…] allows our bodies, particularly our brains, to refresh and repair to maintain physical and mental health”. Mastering deep sleep is like landing a plane: we need to prepare its descent, set up the landing strip, and eventually touch ground. Last week, I shared how to prepare that plane’s descent. Today, you’ll learn how to set up its landing strip: your bedroom. Before we get into it, let’s take a deeper look at deep sleep.

As it turns out, deep sleep is one position on the continuum of autonomic arousal — which governs our energy levels (figure below). We’re on that fascinating continuum as long as we’re alive. The optimal state for most waking activities is in the middle, where we’re both alert and calm. During the first half of the night, we need to spend plenty of time in deep sleep, which is located on the right side of the continuum. This requires a high activation of our so-called parasympathetic nervous system, which is also known as the calmness system:

A high activation of our calmness system, in turn, necessitates a dark, quiet and cool bedroom — for three reasons: light at night decreases activation in that system, destroying our deep sleep; even subtle nightly noises similarly deactivate that system, crushing our chance to get sufficient deep sleep; and your body needs to drop its core temperature by several degrees to get into deep sleep in time. In a nutshell, having a dark, quiet and cool bedroom provides us with the physiological preconditions for plenty of deep sleep.

How to do it

Against this background, the American Academy of Sleep Medicine recommends turning your bedroom into a cave. First, make it dark. Even small amounts of light go through your closed eyelids, which can kill your deep sleep. So, total darkness is critical. Close your blinds, shutters and curtains – and turn off all light-emitting electronics. If that’s not feasible, get a sleep mask. This one from Oura is the best one I’ve come across.

Second, make it quiet. We’re very sensitive to noise when we’re asleep. That noise doesn’t have to be loud, let alone wake us up — even minor acoustic disturbances can destroy your deep sleep. So, total quiet is key. Eliminate all nightly noises in your home, including dishwashers and washing machines. If that’s not possible, use earplugs. The ones from Manta Sleep are both effective and affordable.

Third, make it cool. The recommended bedroom temperature for great sleep might surprise you: it’s between 18 and 22 degrees Celsius. Thus, set your bedroom temperature as close to 18 degrees as you can tolerate. Yet, don’t worry. You don’t need to shiver at night to maintain that temperature: feel free to use as many sheets as you need.

Again, getting to 90 minutes of deep sleep is like landing a plane. Last week, I shared how to prepare that plane’s descent. Today, you’ve learned how to set up its landing strip. If you opt for a sleeping mask and/or earplugs, this even works in hotel rooms.

Next week, I’ll share the most effective and science-based methods to touch ground (i.e., fall asleep).