Qualy #129 - Evolutionary reasons to sleep

**Peter Attia** (0:11)
Welcome to a special bonus episode of The Peter Attia Qualys, a member exclusive podcast. The Qualys is just a shorthand slang for qualification round, which is something you do prior to the race, just much quicker. The Qualys highlight the best of the questions, topics and tactics that are discussed in previous episodes of The Drive. So if you enjoy the Qualy, you can access dozens more of them through our membership program.
Without further delay, I hope you enjoy today's Qualy.

**Matthew Walker** (0:40)
Firstly, you know, it took mother nature 3.6 million years to put this eight hour thing called a night of sleep in place.
And within the space of 70 years, if you look at the data, we've lopped off almost 20 to 25% of that. You know, imagine coming along and saying, you know, in the next hundred years, I think what I'm going to do is for the entirety of human society, I'm going to reduce their oxygen saturation by about 20 to 25%. Do you think that's a good idea? And the answer is no.

**Peter Attia** (1:12)
No, it's such a great example. I'll pause for a moment just to tell a funny story that you and I have talked about off mic, which is up until about 2012, I was in the I'll sleep when I'm dead camp. And I know what led to that. It wasn't, it was a very deliberate decision at the end of medical school when a good friend of mine, with all the best intentions, who was a year ahead of me, so he was now in, at the end of his internship as I was about to begin mine.
He said, and this is in the days when we didn't have the 80 hour work week requirement in residency, so we averaged, I think, about 114 hours a week in the hospital. So he said to me, look Peter, you're signing up for whatever, five, seven years of this thing.
If you spent every moment outside of the hospital sleeping, you would still be tired. The only difference is you wouldn't have any fun. So make sure you live every moment that you're not in the hospital to the fullest. And so for me, that basically meant if I wasn't in the hospital, I was swimming, I was going out with my friends, I was trying to meet girls, like I was doing anything and everything. Such that during that period of my life, I just know, because I was pretty adamant about recording how much time, like I was very wed to this idea, there's 168 hours in a week. If I'm spending 114 of them here, and I spend this many driving, and I spend this many getting groceries, and I spend this many swimming, and blah, blah, blah, blah, blah. I think I was about 28 hours a week of sleep. So it wasn't four every night, because you'd have none, and then six, and then three, and then eight, like you could binge sleep from time to time. But it was pretty much 28 a week. I'll come back to some of the implications of that. But fast forward a few years, I'm talking to a good friend of mine, Kirk Parsley, who's a physician, who, like you, is adamant about the importance of sleep. And we're having dinner one night. And he says, he's challenging me on this. And he says, so let me get this straight. You've just decided that you're gonna sleep half of what is evolutionarily programmed. And I said, yeah.
He goes, does it strike you as odd that evolution would have designed us to spend a third of our life not mating, not watching out for predators, not hunting for food, but doing this thing for some other purpose? Do you think that thing must have been important? And it was such an obvious argument, but it really overnight changed the way I thought about this, which was evolution went to great lengths to do this, and superficially at great cost to us, right? I mean, you could argue, well, imagine you didn't need to sleep, and you could spend 24 hours a day foraging for food or a mate or some other thing, but it didn't.
It didn't, so it's sort of like, there's probably a reason we are not anaerobic, to your point about reducing oxygen saturation by 25%.

**Matthew Walker** (4:03)
If you were to think about that, during sleep, just as you said, you're not eating, you're not finding food, you're not finding a mate, you're not reproducing, you're not caring for your young, you're vulnerable to predation on any one of those grounds, but especially all of them put together as a collective.