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Why Sleep When You Can Drink Coffee? (Part 3)

By Craig Jensen | January 27, 2016

My two previous blogs discussed both coffee/caffeine and sleep, to an extent, and the way they operate individually.  Now let's address an important question regarding their overlap with one another: Can coffee be an effective replacement for sleep when it comes to brain functioning and mental capabilities, specifically with learning and memorizing? Unfortunately, the answer is a resounding "not really". To see why this is true, let's briefly look at the three main components of learning/memorizing:

• Acquisition/encoding, which is the actual experiencing of something new
• Consolidation/storage, where information is made smaller and committed to memory
• Recall/retrieval, which is the ability to remember a memory later on

Acquisition and recall happen while you are awake: you consciously consume new information or try and remember old information. However, consolidation-which is essential to learning and remembering something long term because it is when our brain forms new neural connections to store information-happens mostly during sleep.

A recent study performed by researchers at Johns Hopkins and UC-Irvine found that caffeine can in fact help memory consolidation if it is consumed shortly after someone learns something new. This would suggest that it does impact step 2, even though the caffeine is consumed while you are awake and consolidation happens while you are asleep. Without sleep, the impact of the caffeine on memory would be negligible because there wouldn't be time for the brain to actually perform the task of consolidation anyway.

One of the biggest reasons why we cannot learn well without enough sleep is because of the timing of when we memorize things during sleep and how long it takes for one cycle of sleep to complete. Just like the repairing of our muscles, our brain restores itself most during deep sleep (stages 3 and 4 of NREM) and REM sleep. It takes roughly 70-90 minutes for our body to enter into REM sleep, which is the most important stage for learning and memory. Once there, we only spend about 20 minutes in REM during our first sleep cycle. As we progress into further cycles, we begin to spend more and more time in REM sleep.

So, it is easy to see why we do not learn well when we aren't sleeping well: our brains need a good amount of time in REM sleep, but we don't get it unless we stay asleep for multiple cycles. Adults need roughly 7.5-9 hours of sleep per night (yikes, I never get that much) to be fully functional (some need more and a few less), which is roughly 4-6 cycles of sleep. Thus, sleeping 4-6 hours a night means you could be missing multiple cycles of REM-rich sleep that you need for your brain to consolidate memories and remember processes. And this is only talking about missing one night of good sleep. The reality is that many of us are consistently losing sleep on a night-to-night basis, resulting in sleep deprivation.

Unfortunately, something many people may not know is that sleep deprivation is cumulative. This means that if you go 5 days in a row with those 4-6 hours of sleep, you could be 10-20 hours in debt, rather than just a couple hours from an individual night. Because the amount you need to sleep does not reset from night to night, over time this built up sleep debt will cause you to consistently perform worse in almost every area-cognitive, physical, reaction time, etc.

While coffee can help a little bit for a short time to combat this, it simply cannot overcome such a significant and powerful phenomenon. Plus, the extra jolt you get from coffee to help ward off sleep deprivation probably isn't making you more focused than you would be if you had a proper amount of sleep. Rather, it is simply trying to get you close to the level of efficiency you would be operating at if you had the right amount of sleep in the first place.

And, when the coffee wears off, you will feel extra tired because your brain is being overloaded with the sleep-inducing chemical adenosine that the caffeine is no longer blocking. With this in mind, the conclusion is that there is simply no replacement for sleep. Almost all the research shows that sleep is potentially the most important thing you can do for your emotional, physical, and mental health, and for your ability to learn.

Coffee can help you to an extent when you aren't able to rest up fully, but it can never truly serve as a replacement for a good night's rest, especially when it comes to your ability to learn and remember things. Ultimately, your ability to concentrate, perform, and learn is at its prime when you have the right number of hours of sleep, not the right number of cups of coffee.

Happy sleeping, enjoy your coffee, and happy learning,

Craig.