Ejo #153 – The Coffee Nap

I’m a shift worker so getting a good night’s sleep isn’t always easy.  In fact, as a rule, it’s virtually impossible. I often have to get up for work at 4am, and on other days I don’t get home until 7am.  It’s quite ridiculous if you think about it.  However, as an air traffic controller I do get paid very well to work around the clock, and I’m not here to complain about it.  In fact, I wouldn’t give up shift work for anything in the world (except maybe retirement).  And I certainly wouldn’t ever want to work office hours. Ever again. For as long as I live. 

Shift work isn’t for everyone, but I love it, and you’ll hear more about that in next month’s ejo.  But it does have its pitfalls and the biggest one is fatigue.  Ask any shift worker.  We are always tired.  So very, very tired.  As a result, coffee and naps are both extremely important, and very necessary, tools for us.  I’ve always been a bit of a coffee fiend, but did you know that I also love my siestas.  Picture it:  I get out of bed at 4am to shower, wash my hair, and get ready for work.  I arrive at the tower at 5.30am to start my eight hour shift at 6am.  At 2pm I am relieved from duty and go home.  I usually arrive around 3pm.  What do you think is the first thing I do when I walk in the door?  I’ll tell you.  I flop face first onto the couch and I stay there for the next two hours.  This is not an ideal situation.  But, this invariably used to be my morning shift routine. Until I discovered coffee naps. 

So, what the hell is a coffee nap anyway?  Coffees and naps don’t go together!  That doesn’t make any sense.  Coffee keeps you awake, right?  How are you going to sleep if you drink coffee?  Well yes, it is true that caffeine is a stimulant.  But the secret of the coffee nap is caffeine takes about 20 minutes to reach the blood-brain barrier and slot into the receptors that allow it to take effect (I’m talking about that familiar java jolt).  If those receptors are free and open, then the caffeine will bind to them and you’ll get the caffeine hit that you need.  However, if those receptors happen to be already blocked by something else, then the coffee won’t have the stimulating effect you yearn for.  It will simply be flushed out of the body and you’ll still feel tired and cranky. 

One of the by-products of energy production in the body is adenosine, a molecule that makes you feel sleepy through suppression of nerve cell activity.  When adenosine is present, it binds to the A2A receptors in the brain.  These receptors are super important in regulating oxygen consumption, blood flow through the heart, and central nervous system neurotransmitters.  But psst, guess what else binds to A2A receptors?  Big reveal, yup, it’s caffeine.   

What that means is that when you feel tired and decide to have a coffee, the caffeine and the adenosine have to duke it out and compete to sit in those receptors.  So having a coffee when you’re tired doesn’t always work.  The adenosine in the receptors essentially cock-blocks the caffeine.  What we need to do is somehow clear the A2A receptors of adenosine to ensure that by the time the caffeine in our double espresso reaches them, it gets the red carpet treatment and is escorted directly to the receptor.  Once bound to the receptor the caffeine instantly makes us feel more awake. 

So, how to ensure that the A2A receptors in the brain are available?  Enter the coffee nap’s special sauce.  You might want to sit down for this.  Sleeping (or even just resting, or lying down with your eyes closed) clears the brain’s receptors of adenosine.  So if you have a quick shot of strong coffee and then lie down for twenty minutes, your brain will eliminate the adenosine, ensuring that the A2A receptors are wide open and receptive to the caffeine right about the time it penetrates the blood-brain barrier. 

I literally just woke up from a coffee nap right now (I’m not even joking), and decided to have a bash at creating some terrible graphics to visually demonstrate exactly how all of this works. 

As you can see from my very scientific drawings, the caffeine molecule quite closely resembles the adenosine molecule. And even though the two molecules produce diametrically opposite results (caffeine wakes you up, and adenosine makes you sleepy), the A2A receptors in the brain are unable to differentiate between them.

The A2A receptors just sit there, waiting for either adenosine or caffeine to come along and have a seat. They’re not fussy. For them, it’s like whatever. Also, they may, or may not, actually look like coffee cups.

The caffeine and adenosine compete for a comfy spot in an A2A receptor. It’s a case of first come, first served.

This is what being sleepy looks like. There are many complex processes happening in the body that result in adenosine production. We don’t need to know what they are, but we do need to know that when enough adenosine is produced, we feel irresistibly tired and just want to close our eyes and lie down.

You might think that having a coffee would help to fight the tiredness. That is coffee’s job, after all.

But you’d be wrong. The caffeine is unable to bind to the A2A receptors because they’re already full of snoozing adenosine molecules that are quite happy where they are, thank you very much. So the caffeine is simply swept away and flushed down the toilet.

But if you had that cup of joe and then took a quick nap, the brain would start to clear the adenosine out of the A2A receptors (because that’s what the brain does when you rest).

After twenty minutes, the caffeine arrives on the scene just as the adenosine is being swept away, allowing it free and easy access to the A2A receptors, and blocking any reuptake of adenosine. Clever brain.

The result is that you wake up feeling not just the benefits of having cleared the adenosine, but also of the caffeine punching directly into your brain!! It’s a double whammy. And… it works.

I had my first coffee nap on 26th January 2018, and the fact that I know this might give you an indication of how much this hack has changed my life.  I no longer waste entire afternoons, late mornings or evenings snoring on the couch. If I’m tired (and I’m always tired, I told you I was a shift worker, right?), I simply set an alarm, guzzle a strong espresso and lie down for twenty minutes. Now this sounds easy, and I do promise you that it works… if you do it right. So here are some guidelines to help you achieve the perfect coffee nap.

  1. Find a nice quiet and comfortable spot to lie down. Somewhere you won’t be disturbed for a while.
  2. You need around 200mg of caffeine. And you need to drink it fast. No point sipping it over a few minutes, as that eats into your nap time. A large espresso usually works for me. I let it cool down a little so that I can chug it in one gulp. Cold brew works too.
  3. You really need to set an alarm. And you really need to get up after 20 minutes. And you really need to lie down for the full 20 minutes. Any less and you won’t clear out enough adenosine from your brain, meaning the coffee won’t work as well. Any longer and you’ll enter a deeper sleep which will result in you waking up feeling groggy and suffering from sleep inertia. Twenty minutes is the sweet spot, and you have to be disciplined about it.
  4. You don’t need to actually go to sleep for a coffee nap to work. Adenosine is eliminated even when you’re just resting with your eyes closed. I usually find that the first five or so minutes after lying down, my heart and my mind are both racing too much to sleep. But if I persist and just try to relax my body and quiet my mind, I do usually start to drift off after a while. The perfect coffee nap for me is when I do actually fall asleep and my brain just suddenly wakes up, seconds before the alarm goes off. That, my friends, is the holy grail of coffee naps. That’s what we’re all looking for. It won’t always happen like that, but when it does… bliss.
  5. A coffee nap works when you’re sleepy. Most people, even us poor shift workers, don’t start feeling drowsy until after lunch. I’d say the ideal time for a coffee nap is between 12pm and 4pm, but you can do it later if you really need to. Just be careful not to have it within 6 hours of your bedtime or you’ll have trouble sleeping (which will make you more tired the next day – it’s a vicious cycle, but you can break it).

In the last four and a half years, I’ve had hundreds of coffee naps. I’ve coffee napped in the car, I’ve coffee napped on the floor, I’ve coffee napped in airport lounges, I’ve coffee napped at work, I’ve coffee napped on the couch, I’ve coffee napped my way around Europe and of course I’ve had many, many coffee naps on my bed. The best thing about the coffee nap is that it’s better than just a nap, and it’s better than just a cup of coffee. And it only takes about 25 minutes of your day (I’m adding five minutes for setting everything up and then cleaning the coffee cup afterwards). I’m so excited about this awesome bio-hack, and have introduced many of my friends and family to the benefits of a quick 20 minute coffee nap. My hope is that you’ll try it, and find that it works for you too.

P.S. You’re welcome.


  1. Coffee naps are great. I’m not a shift worker, and I don’t use them often, but there is one situation where they fit right in for me.
    If I feel tired towards the end of the day (often a Friday afternoon) and I have plans for the evening, that’s when the coffee nap comes into play.

    1. Sounds like you already know what’s up! Good for you. Friday afternoon before a big night is absolutely perfect.

      I often think that perhaps I’m over-using coffee naps. But apart from naps, I don’t drink coffee anymore so I figure it all balances out.

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