What Is a Coffee Nap? It’s Not as Crazy as It Sounds!

Even if some lifestyle sites claim otherwise, coffee and sleep are mutually exclusive. This is because the activating alkaloid caffeine occupies the adenosine receptors in the brain, which are actually reserved for the fatigue-inducing hormone adenosine. With this knowledge, the idea of a coffee nap seems absurd. Supposedly, drinking coffee before napping makes the experience even more relaxing and effective.

What sounds like a Reddit or Wikipedia hoax has provided the material for countless studies and investigations. And almost all come to the same conclusion: the combination of napping and caffeine actually seems to have a meaningful effect. So, how is that possible? Let’s look at the science behind coffee naps.

Short Break: What Is a Power Nap?

Power Napping is a modern term, but the idea behind it is as old as civilization.

With a short nap, we relax our head and body before starting again with full energy levels. Usually the best time is right after lunch, as we can thus avoid the dreaded midday slump or the late afternoon crash.

The term was coined in 1998 by James B. Maas (“Power Sleep: The Revolutionary Program That Prepares Your Mind for Peak Performance”).

Incidentally, numerous studies and experiments have factually proven both the existence of the afternoon crash (Hayashi et al. 1999) and the effectiveness of naps (for an overview, see, for example, George 2018 or Lovato et al. 2010).

20-Minute Nap Instead of Sleep: This Is How a Power Nap Works

The differences between “real” sleeping in bed and a nap on the couch are immediately apparent. If you lie under a warm comforter, you want to stay there for a few hours. However, with power napping, we don’t want to fall asleep properly or sleep for several hours.

Both versions are effective in breaking down excess adenosine in the body in order to drive away fatigue. When napping, we also treat ourselves to the opportunity to relax the eyes, aid digestion and empty our brains a little.

Scientists agree that you can achieve the best napping effect by doing so for no more than 20 minutes. Any longer and you get into “real” sleep phases such as deep sleep.

If we are interrupted during these phases, we wake up with exactly the sleep inertia symptoms that napping is supposed to prevent – disorientation, fatigue and inattention (for comparison Max Planck Institute for Psychiatry).

Still, why 20 minutes of all things should be best for the brain and adenosine level without “real” sleep hasn’t been clarified in any studies and in any test subjects. I guess that’s because we generally know too little about the science behind sleeping.

The Caffeine Trick: What Is a Coffee Nap?

Caffeine seems to be used for pretty much everything – as a booster when losing weight, as a metabolism turbo charger and as a legal doping agent in sports. So I shouldn’t be surprised that it’s now supposed to help you achieve a more relaxing nap.

The “idea” for the coffee nap comes from scientists at Loughborough University in England and was studied in several scenarios in the late nineties (e.g. Horn & Reyner 1996 and Horn & Reyner 1997). The basics work like this:

So how do coffee naps work? Well, if you drink a cup of coffee before your little nap and lie down immediately, your brain and caffeine fight the adenosine in your body with double power. Plus, upon waking the caffeine kicks in, banishing all remnants of fatigue and disorientation.

In addition, you can think of coffee before a power nap as an insurance policy not to accidentally sleep the day away at work.

Interestingly, the effectiveness of a coffee nap was accepted relatively quickly by the scientific community, even if there are only a few further studies (such as Hayashi et al. 2003).

This approval is certainly also due to the fact that the idea of a coffee nap seems completely logical: caffeine as a sleep killer plus the 20-minute time window of sleep units and effectiveness is the perfect complement to the other findings.

Advanced Caffeine Nap: How Good Sleep Keeps the Adenosine Receptors at Bay

With all the clarity and logic, there are still some ambiguities about napping after lunch, which are described as the Nap Paradox (cf. Mantua & Spencer 2017).

There’s no consensus on who actually benefits from a short nap, when and in what form – and how to avoid mistakes. In true researcher fashion, naps must first be divided into three categories (cf. Lastella et al. 2021):

In addition, a distinction is made between an “induced” nap and habitual or necessary naps (essential napping).

It seems that a “gratuitous” nap (i.e. appetizing and/or essential) helps less against fatigue and can even be bad for you (Mantua & Spencer 2018).

It is fitting that those who never take a nap and don’t ever drink coffee won’t benefit at all from a sudden desire to nap. Turns out, they’ll have problems falling asleep in the evening and confuse their entire sleep rhythm (cf. Max Planck).

On the other hand, if you regularly nap (not daily!) and want to combat the midday slump for preventative reasons, you can actually feel much better after 20 minutes. And that’s with or without coffee (Hayashi et al. 1999). Similarly, a replacement nap is definitely not a substitute for proper sleep and a regular, individual sleep rhythm in the long run.

What Is the Importance of the Right Time for a Nap?

Of course, scientists are not only tinkering with the 20-minute rule for the optimal sleep phase. They are also studying the ideal time for a normal person to lie down for a power or coffee nap.

“Normal” primarily refers to 9 to 5 workers who always get up around six or seven and are in bed by ten. So, if we take a normal working day as a basis, the best time to nap seems to be around 2 p.m. (e.g. Leong et al. 2022).

Those who nap earlier turn the midday slump into a residual afternoon slump. What’s more, those who nap later ruin their night’s sleep and open up a vicious circle of fatigue, naps and feeling even more sleep deprived.

Coffee or Energy Drinks: Which Caffeine for a Coffee Nap?

Caffeine is always caffeine, but not all caffeinated drinks are necessarily suitable for a coffee nap. This starts with a something as simple as the amount of liquid:

You quickly drank an espresso after lunch. On the other hand, a regular cup of coffee would have taken longer to drink. This means that the 20-minute caffeine clock would have started ticking long before you lay down.

A second important factor is the amount of caffeine per nap unit. Every person has an individual threshold where caffeine works effectively, badly or not at all. In sports, for example, at least 3-6 milligrams of caffeine per kilogram of body weight are needed to achieve performance enhancement. The 3-milligram limit is also frequently used in everyday life.

Incidentally, you can find the caffeine levels in various coffee drinks by checking out my comprehensive caffeine study.

If you don’t like coffee and prefer sugary soda or Red Bull, you should think again. And not only in terms of a coffee nap.

That’s because the mixture of caffeine, sugar and substances such as taurine works faster than caffeine for many people – and ensures a massively accelerated cardiovascular system (see, for example, Ishak et al. 2012).

Sure, tiredness is no longer an issue. Probably not even if you really want to go to sleep. And if your nerve cells are almost vibrating with energy, that’s no better than being tired. So, working on Monster or Red Bull is not a good combination.

However, as with coffee and caffeine, individual tolerance limits apply here, which are largely determined by your habitual consumption.

What About Coffee After Waking Up?

Let’s turn the coffee nap into a nap coffee. In other words, does caffeine help even after half sleep?

If you still have too much adenosine floating around in your brain, one to two cups of coffee after the sleep phase can of course also help to keep it in check. However, that kind of makes the coffee nap “trick” obsolete.

In addition, according to current scientific evidence, you might remember that each of us should have a “cut-off time” for our last coffee of the day.

Since the body needs a while to break down the caffeine again, you mustn’t surpass your limit. That is, unless if you only want to doze in half-sleep later rather than sleeping really deeply (cf. Gardiner et al. 2023).

Coffee Nap: A Better-Than-Expected Trick

I continue to argue that caffeine and coffee should not just be reduced to their effect on the brain and body. After all, coffee is neither a medicine nor a poison. It is a stimulant with (desirable or negative) consequences and should be consumed with care.

However, compared to coffee as a weight loss aid or the fear of caffeine poisoning, the coffee nap seems a lot less contradictory. Plus, it works exactly as science thinks it should. When media outlets talk about the “coffee nap trick,” they are right for once. Weird.

Coffee Nap FAQs