What would happen if you didn’t sleep? - Claudia Aguirre

14,289,135 views ・ 2015-11-12

TED-Ed


Please double-click on the English subtitles below to play the video.

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In 1965, 17-year-old high school student, Randy Gardner
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stayed awake for 264 hours.
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That's 11 days to see how he'd cope without sleep.
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On the second day, his eyes stopped focusing.
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Next, he lost the ability to identify objects by touch.
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By day three, Gardner was moody and uncoordinated.
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At the end of the experiment, he was struggling to concentrate,
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had trouble with short-term memory,
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became paranoid,
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and started hallucinating.
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Although Gardner recovered without long-term psychological
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or physical damage,
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for others, losing shuteye can result in hormonal imbalance,
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illness,
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and, in extreme cases, death.
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We're only beginning to understand why we sleep to begin with,
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but we do know it's essential.
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Adults need seven to eight hours of sleep a night,
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and adolescents need about ten.
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We grow sleepy due to signals from our body
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telling our brain we are tired,
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and signals from the environment telling us it's dark outside.
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The rise in sleep-inducing chemicals,
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like adenosine and melatonin,
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send us into a light doze that grows deeper,
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making our breathing and heart rate slow down
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and our muscles relax.
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This non-REM sleep is when DNA is repaired
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and our bodies replenish themselves for the day ahead.
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In the United States,
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it's estimated that 30% of adults and 66% of adolescents
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are regularly sleep-deprived.
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This isn't just a minor inconvenience.
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Staying awake can cause serious bodily harm.
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When we lose sleep,
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learning,
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memory,
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mood,
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and reaction time are affected.
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Sleeplessness may also cause inflammation,
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halluciations,
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high blood pressure,
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and it's even been linked to diabetes and obesity.
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In 2014, a devoted soccer fan died
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after staying awake for 48 hours to watch the World Cup.
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While his untimely death was due to a stroke,
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studies show that chronically sleeping fewer than six hours a night
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increases stroke risk by four and half times
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compared to those getting a consistent seven to eight hours of shuteye.
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For a handful of people on the planet who carry a rare inherited genetic mutation,
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sleeplessness is a daily reality.
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This condition, known as Fatal Familial Insomnia,
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places the body in a nightmarish state of wakefulness,
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forbidding it from entering the sanctuary of sleep.
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Within months or years,
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this progressively worsening condition leads to dementia and death.
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How can sleep deprivation cause such immense suffering?
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Scientists think the answer lies with the accumulation of waste prducts
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in the brain.
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During our waking hours,
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our cells are busy using up our day's energy sources,
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which get broken down into various byproducts,
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including adenosine.
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As adenosine builds up,
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it increases the urge to sleep, also known as sleep pressure.
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In fact, caffeine works by blocking adenosine's receptor pathways.
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Other waste products also build up in the brain,
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and if they're not cleared away, they collectively overload the brain
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and are thought to lead to the many negative symptoms of sleep deprivation.
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So, what's happening in our brain when we sleep to prevent this?
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Scientists found something called the glymphatic system,
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a clean-up mechanism that removes this buildup
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and is much more active when we're asleep.
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It works by using cerebrospinal fluid to flush away toxic byproducts
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that accumulate between cells.
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Lymphatic vessels, which serve as pathways for immune cells,
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have recently been discovered in the brain,
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and they may also play a role in clearing out the brain's daily waste products.
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While scientists continue exploring the restorative mechanisms behind sleep,
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we can be sure that slipping into slumber is a necessity
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if we want to maintain our health and our sanity.
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