How caffeine and alcohol affect your sleep
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0:00 - 0:04Many of us like to start the day
with a cup of coffee -
0:04 - 0:07and perhaps end the day
with a glass of wine -
0:07 - 0:09or some other kind of alcoholic drink.
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0:09 - 0:12But it turns out
that these two substances, -
0:12 - 0:17alcohol and caffeine,
can have surprising impacts on our sleep. -
0:17 - 0:19[Sleeping with Science]
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0:19 - 0:22(Music)
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0:22 - 0:24Let's start with caffeine.
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0:24 - 0:26Caffeine is in a class of drugs
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0:26 - 0:30that we call the psychoactive stimulants.
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0:30 - 0:33And everyone knows that caffeine
can make them more alert. -
0:33 - 0:35It can wake them up.
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0:35 - 0:37But there are at least two additional,
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0:37 - 0:40hidden features of caffeine
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0:40 - 0:42that some people may not be aware of.
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0:42 - 0:47The first is the duration
of action of caffeine. -
0:47 - 0:49Caffeine, for the average adult,
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0:49 - 0:52will have what we call a half-life
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0:52 - 0:54of about five to six hours.
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0:54 - 0:57What that means is that
after about five to six hours -
0:57 - 1:0150 percent of that caffeine that you had
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1:01 - 1:04is still circulating in your system.
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1:04 - 1:08What that also means
is that caffeine has a quarter-life -
1:08 - 1:11of about 10 to 12 hours.
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1:11 - 1:14In other words, let's say
that you have a cup of coffee -
1:14 - 1:16at 2pm in the evening.
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1:16 - 1:20It could be that almost
a quarter of that caffeine -
1:20 - 1:24is still swilling around
in your brain at midnight. -
1:24 - 1:28And as a result, it can make
it harder for an individual -
1:28 - 1:31to fall asleep or even stay asleep soundly
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1:31 - 1:33throughout the night.
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1:33 - 1:35So that's the first feature of caffeine.
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1:35 - 1:38The second issue with caffeine
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1:38 - 1:41is that it can change
the quality of your sleep. -
1:41 - 1:43Now some people will tell me
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1:43 - 1:45that I'm one of those individuals
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1:45 - 1:47who can have an espresso with dinner,
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1:47 - 1:51and I fall asleep fine,
and I can stay asleep. -
1:51 - 1:53But even if that's true, it turns out
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1:53 - 1:56that caffeine can actually
decrease the amount -
1:56 - 2:00of deep, non-rapid eye movement
sleep that we have, -
2:00 - 2:03stages three and four of non-REM sleep.
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2:03 - 2:06That's that sort of
restorative deep sleep. -
2:06 - 2:09And as a consequence,
you can wake up the next morning, -
2:09 - 2:11and you don't feel refreshed,
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2:11 - 2:14you don't feel restored by your sleep.
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2:14 - 2:15But you don't remember waking up,
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2:15 - 2:18you don't remember
struggling to fall asleep, -
2:18 - 2:20so you don't make the connection,
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2:20 - 2:23but nevertheless
you may then find yourself -
2:23 - 2:27reaching for two cups of coffee
in the morning to wake up -
2:27 - 2:28rather than one.
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2:28 - 2:33So that's caffeine,
but now let's move on to alcohol, -
2:33 - 2:35because alcohol is perhaps one
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2:35 - 2:39of the most misunderstood
sleep aids out there. -
2:39 - 2:43In fact, it's anything but a sleep aid.
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2:43 - 2:45And it can be problematic for your sleep
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2:45 - 2:47in at least three different ways.
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2:47 - 2:50First, alcohol is in a class of drugs
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2:50 - 2:52that we call the sedatives.
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2:52 - 2:55But sedation is not sleep.
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2:55 - 2:57And studies teach us that those two things
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2:57 - 2:59are really quite different.
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2:59 - 3:01Sedation is a case
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3:01 - 3:04where we're simply
switching off the firing -
3:04 - 3:08of the brain cells,
particularly in the cortex. -
3:08 - 3:10And that's not natural sleep.
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3:10 - 3:13In fact, during deep
non-rapid eye movement sleep, -
3:13 - 3:18for example, the brain has
this remarkable coordination -
3:18 - 3:21of hundreds of thousands of cells
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3:21 - 3:23that all of a sudden fire together,
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3:23 - 3:24and then they all go silent,
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3:24 - 3:27and then they all fire together,
and then they go silent, -
3:27 - 3:30producing these big, powerful brainwaves
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3:30 - 3:33of deep non-REM sleep.
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3:33 - 3:34And so that's the first way
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3:34 - 3:37in which alcohol can be problematic.
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3:37 - 3:40We're mistaking sedation for deep sleep.
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3:40 - 3:43The second problem with alcohol
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3:43 - 3:46is that it can actually
fragment your sleep. -
3:46 - 3:50Alcohol can actually trigger
and activate during sleep -
3:50 - 3:52what we call the fight or flight branch
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3:52 - 3:54of the nervous system,
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3:54 - 3:57which will therefore
wake you up more frequently -
3:57 - 3:58throughout the night.
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3:58 - 4:00And alcohol can even increase the amount
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4:00 - 4:04of alerting chemicals
that are released by the brain, -
4:04 - 4:07once again fragmenting your sleep.
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4:07 - 4:11The third and final issue
with alcohol and sleep -
4:11 - 4:13is that alcohol can actually block
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4:13 - 4:17your rapid eye movement sleep,
or your dream sleep. -
4:17 - 4:19And as we'll learn in subsequent episodes,
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4:20 - 4:22REM sleep, or rapid eye
movement sleep, dream sleep, -
4:22 - 4:25provides a collection of benefits,
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4:25 - 4:27things such as your emotional
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4:27 - 4:30and mental health, even creativity.
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4:30 - 4:34Now I'm not here
to tell anyone how to live. -
4:34 - 4:36I don't want to be puritanical.
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4:36 - 4:38I'm just a scientist.
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4:38 - 4:40What I want to try and do is provide you
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4:40 - 4:43with the information
about the relationship -
4:43 - 4:46between caffeine and alcohol on your sleep
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4:46 - 4:49so then you can make an informed choice
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4:49 - 4:52as to how best you want to live your life
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4:52 - 4:55when you're trying to
prioritize your sleep health.
- Title:
- How caffeine and alcohol affect your sleep
- Speaker:
- Matt Walker
- Description:
-
Caffeine wakes you up, and alcohol makes you nod off, right? It's not that simple. Sleep scientist Matt Walker takes us into the eye-opening ways that these drinks affect the quantity and quality of our sleep.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED Series
- Duration:
- 04:54
Erin Gregory edited English subtitles for How caffeine and alcohol affect your sleep | ||
Erin Gregory approved English subtitles for How caffeine and alcohol affect your sleep | ||
Erin Gregory edited English subtitles for How caffeine and alcohol affect your sleep | ||
Joanna Pietrulewicz accepted English subtitles for How caffeine and alcohol affect your sleep | ||
Joanna Pietrulewicz edited English subtitles for How caffeine and alcohol affect your sleep | ||
Joanna Pietrulewicz edited English subtitles for How caffeine and alcohol affect your sleep | ||
Brian Greene edited English subtitles for How caffeine and alcohol affect your sleep | ||
Brian Greene edited English subtitles for How caffeine and alcohol affect your sleep |