Moment 141: What Coffee Is REALLY Doing To Your Sleep!: Matthew Walker

The Diary Of A CEO with Steven Bartlett

Friday, 22 December 2023 - 14 minutes

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, which means if you have a cup of coffee at midday, a quarter of that caffeine is still in your brain at midnight.

Secondly, as a stimulant, caffeine mutes the chemical, adenosine, which is in charge of sleepiness. However, the adenosine is still there and builds, so when caffeine leaves your system you get a caffeine crash, which is all the sleepiness that has been built up hitting at once.

Finally, caffeine blocks deep sleep by between 15 to 30%. So even if you are able to fall asleep after drinking coffee, it will be poor quality sleep, and you lose out the amazing benefits of deep sleep, such as: regulating your cardiovascular system, replenishing the immune system, and securing new memories into your brain.

However, Matthew doesn’t say that people should completely give up coffee, but instead the main thing to look out for is how much you drink and the timing of when you drink it.

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