Dr. Matthew Walker

So you become REM sleep deficient. This is the reason that people will sometimes say, you know, we had two or three bottles of wine last night when friends came over at the weekend. And then I slept in late because we went to bed late and I was having these crazy dreams, just wild crazy dreams. What's happened there is that firstly, REM sleep comes mostly in the second half of the night.

So you become REM sleep deficient. This is the reason that people will sometimes say, you know, we had two or three bottles of wine last night when friends came over at the weekend. And then I slept in late because we went to bed late and I was having these crazy dreams, just wild crazy dreams. What's happened there is that firstly, REM sleep comes mostly in the second half of the night.

So you become REM sleep deficient. This is the reason that people will sometimes say, you know, we had two or three bottles of wine last night when friends came over at the weekend. And then I slept in late because we went to bed late and I was having these crazy dreams, just wild crazy dreams. What's happened there is that firstly, REM sleep comes mostly in the second half of the night.

You get most of your deep sleep in the first half of the night. If you're sleeping later into the morning, that's the REM sleep rich phase part of your sleep cycle. So your brain has a different taste preference for what it wants to eat from the finger buffet of the sleep menu at night. Early in the night, all it wants to do is feast on deep sleep, very little REM.

You get most of your deep sleep in the first half of the night. If you're sleeping later into the morning, that's the REM sleep rich phase part of your sleep cycle. So your brain has a different taste preference for what it wants to eat from the finger buffet of the sleep menu at night. Early in the night, all it wants to do is feast on deep sleep, very little REM.

You get most of your deep sleep in the first half of the night. If you're sleeping later into the morning, that's the REM sleep rich phase part of your sleep cycle. So your brain has a different taste preference for what it wants to eat from the finger buffet of the sleep menu at night. Early in the night, all it wants to do is feast on deep sleep, very little REM.

As you go through into the second half of the night, it likes to switch its taste preference to REM. The further you sleep later into the morning, the more REM sleep you get. If you want to increase the amount of REM sleep, one of the things you can do is just sleep half an hour later into that morning and you'll start to get more REM sleep.

As you go through into the second half of the night, it likes to switch its taste preference to REM. The further you sleep later into the morning, the more REM sleep you get. If you want to increase the amount of REM sleep, one of the things you can do is just sleep half an hour later into that morning and you'll start to get more REM sleep.

As you go through into the second half of the night, it likes to switch its taste preference to REM. The further you sleep later into the morning, the more REM sleep you get. If you want to increase the amount of REM sleep, one of the things you can do is just sleep half an hour later into that morning and you'll start to get more REM sleep.

But what alcohol will do is it will start to block the amount of REM sleep that you've been having for most of the night. Your brain is so clever though. Sleep is so strongly conserved across biology, across phylogeny, that sleep emerged, as I said, with living organisms and has stayed there. It's one of the most preserved behaviors that we see in any living organism.

But what alcohol will do is it will start to block the amount of REM sleep that you've been having for most of the night. Your brain is so clever though. Sleep is so strongly conserved across biology, across phylogeny, that sleep emerged, as I said, with living organisms and has stayed there. It's one of the most preserved behaviors that we see in any living organism.

But what alcohol will do is it will start to block the amount of REM sleep that you've been having for most of the night. Your brain is so clever though. Sleep is so strongly conserved across biology, across phylogeny, that sleep emerged, as I said, with living organisms and has stayed there. It's one of the most preserved behaviors that we see in any living organism.

And it's preserved at the level of the stages too. So your brain, what I mean by that is it's understanding how much REM sleep you, Chris, should have had across the night when you've had a few too many drinks. And it keeps a clock counter of how much REM sleep you should have had and you've not obtained.

And it's preserved at the level of the stages too. So your brain, what I mean by that is it's understanding how much REM sleep you, Chris, should have had across the night when you've had a few too many drinks. And it keeps a clock counter of how much REM sleep you should have had and you've not obtained.

And it's preserved at the level of the stages too. So your brain, what I mean by that is it's understanding how much REM sleep you, Chris, should have had across the night when you've had a few too many drinks. And it keeps a clock counter of how much REM sleep you should have had and you've not obtained.

And finally, by those late morning hours on the Saturday when you've slept late, your liver and your kidneys have finally excreted all of the alcohol. So in the last hour or two of sleep, your brain gets the REM sleep it will have normally obtained, plus it tries to get back that which it's lost. And it's called a REM sleep rebound effect.

And finally, by those late morning hours on the Saturday when you've slept late, your liver and your kidneys have finally excreted all of the alcohol. So in the last hour or two of sleep, your brain gets the REM sleep it will have normally obtained, plus it tries to get back that which it's lost. And it's called a REM sleep rebound effect.

And finally, by those late morning hours on the Saturday when you've slept late, your liver and your kidneys have finally excreted all of the alcohol. So in the last hour or two of sleep, your brain gets the REM sleep it will have normally obtained, plus it tries to get back that which it's lost. And it's called a REM sleep rebound effect.

And that's why you have really intense dreaming and you have these really crazy, bizarre experiences. Does your brain get back all of the REM sleep that it lost? No, it doesn't. It can only accumulate about 50% of the debt. So you will still be REM sleep deficient. REM sleep, it turns out, if you want to say... Give the head-to-head challenge, which is more important, non-REM versus REM?

And that's why you have really intense dreaming and you have these really crazy, bizarre experiences. Does your brain get back all of the REM sleep that it lost? No, it doesn't. It can only accumulate about 50% of the debt. So you will still be REM sleep deficient. REM sleep, it turns out, if you want to say... Give the head-to-head challenge, which is more important, non-REM versus REM?