In today's episode, Matt unpacks the world of coffee, and caffeine in the first of a two-part series on caffeine. Matt describes the numerous health benefits associated with coffee, the fact that Matt has even changed his tune a little and advocates a morning cup for some. Matt may not have anything to do with caffeine itself, with more details on that in part 2. In part 1, Matt then takes a deep dive into the different ways in which caffeine negatively impacts your sleep, some of which you may be less familiar with.

The first is that caffeine makes it harder for you to fall asleep. Due to activation of the nervous system, caffeine can lead to that unpleasant experience of a racing mind that won't shut off in bed—almost a Rolodex of anxiety that leads to ruminating and therefore catastrophizing.

The second impact is that caffeine makes it more difficult for you to stay asleep soundly across the night. This is due, in part, to the fact that caffeine makes your sleep more unstable and fragile, so up more frequently at night. The consequence is something that scientists and doctors call sleep fragmentation, meaning that your overall sleep efficiency, or the consistent quality of your sleep, becomes significantly worse when you have caffeine on board.

The third feature that Matt points out centers on caffeine’s duration of action. Caffeine has a half-life of between five to six hours in the average adult. This means that, after five to six hours, 50% of that caffeine is still in your system. What this also means is that caffeine has a quarter-life of approximately 10 to 12 hours for a typical adult.

Here, Matt gives us some context: if you have a cup of coffee at 2 PM, a quarter or more of that caffeine could still be circulating in your brain at midnight. Meaning, if you have a cup of coffee at 2 PM, it may be the equivalent of getting into bed at midnight, and just before you turn the lights out, you swig a quarter of a cup of coffee and you hope for a good night of sleep.

Matt, however, points out that the 10 to 12 hours quarter-life of caffeine is for the average adult, but this varies significantly from one person to the next. He explains in detail why this is the case: based on differences in genetics, different people will have a more or less efficient version of an enzyme that clears caffeine from their system. Some people will have a version of that enzyme that allows them to remove the caffeine from their system very quickly, whereas other people will have a version of the enzyme that is much slower in its speed of clearing caffeine.

Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way.The good people at InsideTracker are the sponsors of this week’s episode, and they are generously offering 25% off any one of their programs for anyone who uses the above link. InsideTracker is essentially a personalized biometric platform that analyzes your blood and your DNA to better understand what's happening inside of you and also offers suggestions regarding things that you can do to better try and adjust some of those numbers, optimize them, and, as a result, optimize you.

So, make your way over to InsideTracker, and take advantage of this incredible deal on this valuable and remarkably convenient service. And, as always, if you have thoughts or feedback you’d like to share, please reach out to Matt on Instagram.

#10: Sleep & Caffeine – Part 1

The Matt Walker Podcast