Andrew Huberman: Sleep, Dreams, Creativity, Fasting, and Neuroplasticity | Lex Fridman Podcast #164

The following is a conversation with Andrew Huberman, his second time on the podcast. He's a neuroscientist at Stanford, a world-class researcher and educator, and now, he has a new podcast on YouTube and all the usual places called Huberman Lab that I can't recommend highly enough. Quick mention of our sponsors, Masterclass Online Courses, Four Sigmatic Mushroom Coffee, Magic Spoon Low Carb Cereal, and BetterHelp Online Therapy. Click the sponsor links to get a discount. By the way, Masterclass is testing to see if they want to support this podcast long-term, so if you're on the fence, now is the time to sign up. And I'm pretty sure Andrew will have a neuroscience masterclass on there soon enough, though his podcast is basically a weekly masterclass in itself. As a side note, let me say that Andrew is a friend and a new collaborator. We're working on a paper together about a topic we're both really passionate about, at the intersection of neuroscience and machine learning. But that's probably many months away from being published. Still, I'm really excited about this work. He's one of the smartest and kindest people I have the pleasure of talking to on this podcast, so I hope we'll talk many more times in the future. If you enjoy this thing, subscribe on YouTube, review it on Apple Podcasts, follow on Spotify, support me on Patreon, or connect with me on Twitter @LexFridman. And now, here's my conversation with Andrew Huberman. Why do humans need sleep? Let's, let's go with the big first question.

Okay well, the answer I'll start with is the one that I always default to when there's a why question, which is, uh, I wasn't consulted at the design phase.

(laughs)

So, (laughs) so, so I wriggle my way out of giving a absolute answer, right? But there's one mechanism that's very clear that's super important, which is that the longer we are awake, the more adenosine accumulates in our brain. And adenosine binds to adenosine receptors, no surprise there, and it creates the feeling of sleepiness, independent of time of day or night. So, there are two mechanisms. One is we get sleepy as adenosine accumulates. The longer we've been awake, the more adenosine has accumulated in our system. But how sleepy we get for a given amount of adenosine depends on where we are in this so-called circadian cycle. And the circadian cycle is just this very, very well-conserved oscillation. It's a temperature oscillation, where you go from a low point, typically if you're awake during the day and you're asleep at night, you'll, your lowest temperature point will be like 3:00 AM, 4:00 AM, and then your temperature will start to creep up as you wake up in the morning, and then it'll peak in the late afternoon, and then it'll start to drop again toward the evening and then you get s- sleep again. That oscillation in temperature takes 24 hours, plus or mi-