logo
episode-header-image
Dec 2021
11m 24s

#10: Sleep & Caffeine – Part 1

DR. MATT WALKER
About this episode

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.


Up next
Jul 7
#101 - The Sleep Prescription To Better Immunity with Dr. Aric Prather
Matt welcomes UCSF sleep expert Dr. Aric Prather to the podcast this week to discuss the science of psychoneuroimmunology: the link between our behavior and immune health. After a primer on the immune system’s innate and adaptive arms, Dr. Prather details how insufficient sleep d ... Show More
54m 49s
Jun 23
The Dreamer Boat: Sophia's Journey, A Sleep Story, read by Matt Walker
Prepare for a tranquil journey into sleep as Matt returns with a voyage aboard "The Dreamer." Let go of the day's events and allow your mind to quiet as we travel to a busy coastal town. Tonight, you’ll meet Sophia, a painter whose vibrant and expressive works reflect the world a ... Show More
29m 26s
Jun 16
#100 - Sleep As The Fountain Of (Facial) Youth
Matt delves into the science of "beauty sleep" this week, revealing it as somewhat of a scientific reality. He highlights research by Dr. Tina Sundelin, which demonstrates that sleep-deprived individuals are consistently perceived as less healthy, more fatigued, and less attracti ... Show More
36m 59s
Recommended Episodes
Dec 2022
Using Caffeine to Optimize Mental & Physical Performance
In this episode, I explain how to use caffeine to enhance mental and physical health and performance, including the optimal dosages and intake schedules for caffeine. I explain how caffeine powerfully reinforces the consumption of certain foods and drinks—thereby increasing how m ... Show More
2h 18m
Dec 2023
Moment 141: What Coffee Is REALLY Doing To Your Sleep!: Matthew Walker
In this moment, sleep expert and author of ‘Why We Sleep’, Matthew Walker discusses the 3 main reasons why caffeine is so terrible for sleep.Firstly, is that the impact of caffeine lasts long after drinking a cup of coffee. Caffeine has a quarter life of between 10 to 12 hours, w ... Show More
14m 55s
Jun 2018
025: Is Coffee Bad For Your Adrenal Health with Dr. Mariza
What We’re Talking About In This Episode! Is coffee feeding your chronic stress or fatigue? All the factors that can influence how coffee affects you How green smoothies helped me replace coffee The difference between caffeine in matcha vs caffeine in coffee Ways to give yourself ... Show More
48m 36s
Jul 2020
Ep 54 Wake Up and Smell the Caffeine
Are you one of the billions of people around the world who starts your day with a freshly brewed and deliciously aromatic cup of coffee or tea or maybe even hot chocolate? Or are you caffeine-avoidant, looking on at your coffee-addicted friends with confusion and maybe even pity? ... Show More
1h 23m
Feb 2024
Coffee, nap, rave, repeat...
Ever wondered how much caffeine is too much? Or whether you’d feel better off if you took an afternoon nap? And with the rise in ‘day raving’ we’ll be looking at whether it’s better for your health to have your night out at 2pm rather than 2am. We’ll learn about the amount of caf ... Show More
28m 52s
Apr 2024
GUEST SERIES | Dr. Matt Walker: How to Structure Your Sleep, Use Naps & Time Caffeine
This is episode 3 of a 6-part special series on sleep with Dr. Matthew Walker, Ph.D., a professor of neuroscience and psychology at the University of California, Berkeley, and leading public educator about the role of sleep in health, disease and performance. We explain how our s ... Show More
2h 18m
Nov 2020
3 ways to get more BENEFITS FROM YOUR COFFEE - Ben Azadi KKP: 203
Yes, coffee can be healthy and help with weight loss. Watch for the benefits of adding fats to your coffee, and 3 ways to enhance your coffee. ☕Healthiest Coffee: http://www.ketokampcoffee.com Use "ketokamp" for 10% off How to Make a Fatty Cup of Coffee (Best Keto Coffee in the W ... Show More
8m 17s
Sep 2023
Michael Pollan Spills the Beans on the Caffeinated Brain
Are you someone who needs a cup of coffee or spot of tea to start the day? Would you be surprised to hear that the key ingredient, the thing that gives you that morning boost - caffeine - is also a psychoactive drug? Whether it’s coffee, tea or soda, people around the world consu ... Show More
32m 22s
Jan 2021
2020's most popular: coffee and its surprising health benefits
Coffee. For some, it is deserving of its own essential food group. But is coffee more than just a way to achieve functioning human capacity first thing in the morning? You may have seen media headlines in the past warning about health risks of coffee. But now that the science has ... Show More
20m 5s