You get to the office or to your favorite café and you take off your coat.
There’s a long list of things you want to get done today, so you had better get right on it. But first—a cup of coffee.
See, many of us enjoy drinking coffee at various times of day. Quality coffee has intricate flavors, so coffee can simply be a pleasure to drink because of its taste.But many of us also drink coffee because it wakes us up or because it helps us focus.
Coffee makes us feel awake because the caffeine latches onto adenosine receptors in our brain. Wait, latches onto what?
Throughout the day, a chemical called adenosine builds up in your brain. As the day progresses, the adenosine level increases and the adenosine hits the adenosine receptors, which makes you feel sleepy. In the evening, you’ll have a lot of adenosine in your brain, which—under normal circumstances—urges you to sleep.
That is, unless you consumed a substantial amount of caffeine. As I said, caffeine latches onto the adenosine receptors, preventing adenosine itself from reaching the receptors—and so you don’t feel as sleepy. Put more simply: caffeine artificially makes you feel awake because it stops a sleep-inducing chemical from doing its job.
This might be exactly what we want. In the morning, if we’re feeling groggy, blocking the adenosine from hitting its receptors might be a welcome feeling. We want to get stuff done, so it helps to be awake. Yay! Productivity!
Particularly on days when we slept poorly, drinking some coffee can help us be awake and focused enough to get work done.
Unfortunately, caffeine stays in our brains for a long time. It has a half-life of around six hours. So six hours after you drink your coffee, half the caffeine you consumed is still hanging around in your brain. And after twelve hours, roughly a quarter of it will still be around. So, if you normally drink two cups of coffee in the morning, then when you head to bed in the evening, you will still have half a cup’s worth of caffeine left in your brain.
And do you normally sleep well if you drink coffee right before bed? Having caffeine floating around your brain at night is the last thing you want.
With caffeine blocking adenosine from reaching its receptors, you can have a hard time falling asleep. Even if you do fall asleep, you might sleep lighter or wake up more often during the day, dramatically reducing the quality of your sleep.
Look, I’ve written about sleep often, and I still struggle to convey the importance of a proper night’s sleep, especially on productivity. Put simply: if you sleep poorly, that will destroy your productivity.
Poor sleep quantity or quality makes your prefrontal cortex much less effective, so you have a harder time thinking logically, organizing your tasks, and prioritizing them. Your control over your emotions suffers. You’re more likely to give into bad habits or choices because you have less willpower available. And those are just some of the short-term effects; sustained poor sleep will massively increase your risk of having all sorts of health problems, from diabetes to Parkinson’s to Alzheimer’s.
In other words, that cup of coffee that has you feeling so focused and productive earlier in the day might come at the cost of your sleep and therefore your productivity (and your health!) the next day.
So, does drinking coffee make you more productive?
The answer is: it depends.
If you drink coffee moderately and early in the day, it can help you stay focused. At the very least, it won’t hurt your productivity.
But if you drink a lot of coffee, or if you drink coffee late in the afternoon or in the evening, the caffeine will lower your sleep quality. And the poor sleep will hurt your productivity the next day.
So my advice to you is: for maximum productivity, don’t drink too much coffee. And if you do drink coffee, then do so in the morning.