Calculate (And Enjoy) The Perfect Night’s Sleep

This is Dr. Michael Breus, a clinical psychologist and sleep specialist, and he wants you to get a good night’s sleep, every night.

First, let’s assume you know a lot of good advice about how to do that already in terms of environment and preparation, etc. If you want a recap before proceeding, then we recommend:

Get Better Sleep: Beyond The Basics

Now, what does he want to add?

Wake up refreshed

Of course, how obtainable this is will depend on the previous night’s sleep, but there is something important we can do here regardless, and it’s: beat sleep inertia.

Sleep inertia is what happens when we wake up groggy (for reasons other than being ill, drugged, etc) rather than refreshed. It’s not actually related to how much sleep we have, though!

Rather, it pertains to whether we woke up during a sleep cycle, or between cycles:

• If we wake up between sleep cycles, we’ll avoid sleep inertia.
• If we wake up during a sleep cycle, we’ll be groggy.

Deep sleep generally occurs in 90-minute blocks, albeit secretly that is generally 3× 20 minute blocks in a trenchcoat, with transition periods between, during which the brainwaves change frequency.

REM sleep generally occurs in 20 minute blocks, and will usually arrive in series towards the end of our natural sleep period, to fit neatly into the last 90-minute cycle.

Sometimes these will appear a little out of order, because we are complicated organic beings, but those are the general trends.

In any case, the take-away here is: interrupt them at your peril. You need to wake up between cycles. There are two ways you can do this:

1. Carefully calculate everything, and set a very precise alarm clock (this will work so long as you are correct in guessing how long it will take you to fall asleep)
2. Use a “sunrise” lamp alarm clock, that in the hour approaching your set alarm time, will gradually increase the light. Because the body will not naturally wake up during a cycle unless a threat is perceived (loud noise, physical rousing, etc), the sunrise lamp method means that you will wake up between sleep cycles at some point during that hour (towards the beginning or end, depending on what your sleep balance/debt is like).

Do not sleep in (even if you have a sleep debt); it will throw everything out.

Caffeine will not help much in the morning

Assuming you got a reasonable night’s sleep, your brain has been cleansed of adenosine (a sleepy chemical), and if you are suffering from sleep inertia, the grogginess is due to melatonin (a different sleepy chemical).

Caffeine is an adenosine receptor blocker, so that will do nothing to mitigate the effects of melatonin in your brain that doesn’t have any meaningful quantity of adenosine in it in the morning.

Adenosine gradually accumulates in the brain over the course of the day (and then gets washed out while we sleep), so if you’re sleepy in the afternoon (for reasons other than: you just had a nap and now have sleep inertia again), then caffeine can block that adenosine in the afternoon.

Of course, caffeine is also a stimulant (it increases adrenaline levels and promotes vasoconstriction), but its effects at healthily small doses are modest for most people, and you’d do better by splashing cold water on your face and/or listening to some upbeat music.

Learn more: The Two Sides Of Caffeine

Time your naps correctly (if you take naps)

Dr. Breus has a lot to say about this, based on a lot of clinical research, but as it’s entirely consistent with what we’ve written before (based on the exact same research), to save space we’ll link to that here:

How To Be An Expert Nap-Artist (With No “Sleep-Hangovers”)

Calculate your bedtime correctly

Remember what we said about sleep cycles? This means that that famous “7–9 hours sleep” is actually “either 7½ or 9 hours sleep”—because those are multiples of 90 minutes, whereas 8 hours (for example) is not.

So, consider the time you want to get up (ideally, this should be relatively early, and the same time every day), and then count backwards either 7½ or 9 hours sleep (you choose), add 20–30 minutes to fall asleep, and that’s your bedtime.

So for example: if you want to have 7½ hours sleep and get up at 6am, then your bedtime is anywhere between 10pm and 10:10pm.

Remember how we said not to sleep in, even if you have a sleep debt? Now is the time to pay it off, if you have one. If you normally sleep 7½ hours, then make tonight a 9-hour sleep (plus 20–30 minutes to fall asleep). This means you’ll still get up at 6am, but your bedtime is now anywhere between 8:30pm and 8:40pm.

Want to know more from Dr. Breus?

You might like this excellent book of his that we reviewed a while back:

The Power of When – by Dr. Michael Breus

Enjoy!