[Script Info]
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[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.13,0:00:01.66,Default,,0000,0000,0000,,So far, we've spoken about
Dialogue: 0,0:00:01.68,0:00:05.54,Default,,0000,0000,0000,,all of the wonderful\Nbenefits that sleep provides,
Dialogue: 0,0:00:05.56,0:00:09.04,Default,,0000,0000,0000,,but how much sleep should\Nwe actually be getting?
Dialogue: 0,0:00:09.06,0:00:11.84,Default,,0000,0000,0000,,[Sleeping with Science]
Dialogue: 0,0:00:11.87,0:00:13.89,Default,,0000,0000,0000,,(Music)
Dialogue: 0,0:00:13.92,0:00:16.94,Default,,0000,0000,0000,,For the average adult,\Nthe current recommendation
Dialogue: 0,0:00:16.96,0:00:20.73,Default,,0000,0000,0000,,is somewhere between seven to nine\Nhours of sleep a night.
Dialogue: 0,0:00:20.75,0:00:24.63,Default,,0000,0000,0000,,And what we've been finding\Nfrom large-scale epidemiological studies
Dialogue: 0,0:00:24.65,0:00:28.45,Default,,0000,0000,0000,,is that, using that reference point\Nof seven to nine hours,
Dialogue: 0,0:00:28.47,0:00:30.46,Default,,0000,0000,0000,,once you start to drop below that,
Dialogue: 0,0:00:30.48,0:00:34.15,Default,,0000,0000,0000,,your mortality risk\Nactually starts to increase.
Dialogue: 0,0:00:34.17,0:00:39.70,Default,,0000,0000,0000,,In fact, the Center for Disease Control\Nin the United States, or the CDC,
Dialogue: 0,0:00:39.72,0:00:43.28,Default,,0000,0000,0000,,they stipulate a minimum\Nof seven hours of sleep a night
Dialogue: 0,0:00:43.30,0:00:44.49,Default,,0000,0000,0000,,for the average adult.
Dialogue: 0,0:00:44.51,0:00:47.23,Default,,0000,0000,0000,,In other words, the shorter your sleep,
Dialogue: 0,0:00:47.25,0:00:48.73,Default,,0000,0000,0000,,the shorter your life.
Dialogue: 0,0:00:48.75,0:00:54.81,Default,,0000,0000,0000,,But it turns out that it's not quite\Na linear relationship as you would expect.
Dialogue: 0,0:00:54.83,0:00:57.96,Default,,0000,0000,0000,,It's not as though the more\Nand more that you sleep,
Dialogue: 0,0:00:57.98,0:01:01.25,Default,,0000,0000,0000,,the lower and lower\Nyour mortality risk is.
Dialogue: 0,0:01:01.27,0:01:03.79,Default,,0000,0000,0000,,In fact, something strange happens.
Dialogue: 0,0:01:03.81,0:01:06.39,Default,,0000,0000,0000,,Once you get past nine hours,
Dialogue: 0,0:01:06.41,0:01:11.12,Default,,0000,0000,0000,,you actually start to see\Na rise back up in mortality risk,
Dialogue: 0,0:01:11.14,0:01:13.34,Default,,0000,0000,0000,,which seems rather strange and peculiar.
Dialogue: 0,0:01:13.36,0:01:18.84,Default,,0000,0000,0000,,And scientists have actually put forward\Nat least two different explanations.
Dialogue: 0,0:01:18.86,0:01:22.63,Default,,0000,0000,0000,,The first is that,\Nif you look at those studies,
Dialogue: 0,0:01:22.65,0:01:28.90,Default,,0000,0000,0000,,it may be that individuals are suffering\Nfrom significant disease and illness.
Dialogue: 0,0:01:28.92,0:01:32.08,Default,,0000,0000,0000,,When we become infected,\Nor we have disease,
Dialogue: 0,0:01:32.10,0:01:35.78,Default,,0000,0000,0000,,typically, we try to sleep longer,\Nwe stay in bed longer.
Dialogue: 0,0:01:35.80,0:01:36.96,Default,,0000,0000,0000,,So in other words,
Dialogue: 0,0:01:36.98,0:01:41.50,Default,,0000,0000,0000,,it was the unmeasured disease\Nand sickness in those studies
Dialogue: 0,0:01:41.52,0:01:45.23,Default,,0000,0000,0000,,that was triggering\Na response in those individuals
Dialogue: 0,0:01:45.26,0:01:46.79,Default,,0000,0000,0000,,to try and sleep more.
Dialogue: 0,0:01:46.82,0:01:48.08,Default,,0000,0000,0000,,That's one explanation.
Dialogue: 0,0:01:48.10,0:01:52.20,Default,,0000,0000,0000,,The second possible explanation\Nis poor sleep quality,
Dialogue: 0,0:01:52.22,0:01:54.88,Default,,0000,0000,0000,,because we know that sleep quality,
Dialogue: 0,0:01:54.90,0:01:58.30,Default,,0000,0000,0000,,independent of sleep quantity,
Dialogue: 0,0:01:58.32,0:02:01.83,Default,,0000,0000,0000,,is also associated with mortality risk.
Dialogue: 0,0:02:01.86,0:02:04.94,Default,,0000,0000,0000,,And the lower that your\Nquality of sleep is,
Dialogue: 0,0:02:04.96,0:02:06.97,Default,,0000,0000,0000,,the higher your risk of death.
Dialogue: 0,0:02:06.100,0:02:11.75,Default,,0000,0000,0000,,People who have poor quality of sleep\Nwill typically try to sleep longer;
Dialogue: 0,0:02:11.78,0:02:17.02,Default,,0000,0000,0000,,they'll try to stay in bed longer\Nto overcome that poor quality of sleep.
Dialogue: 0,0:02:17.04,0:02:22.53,Default,,0000,0000,0000,,It may be poor quality of sleep\Nmasquerading as long sleep
Dialogue: 0,0:02:22.56,0:02:25.67,Default,,0000,0000,0000,,that is associated\Nwith a higher risk of death,
Dialogue: 0,0:02:25.70,0:02:28.22,Default,,0000,0000,0000,,rather than the long sleep itself.
Dialogue: 0,0:02:28.24,0:02:33.34,Default,,0000,0000,0000,,But if we take a step back\Nand think about society overall,
Dialogue: 0,0:02:33.36,0:02:36.84,Default,,0000,0000,0000,,I think modernity is constantly pushing us
Dialogue: 0,0:02:36.86,0:02:42.11,Default,,0000,0000,0000,,to, perhaps, work long hours\Nand therefore neglect our sleep.
Dialogue: 0,0:02:42.14,0:02:46.38,Default,,0000,0000,0000,,But if we want to be around\Nlong enough to get the benefits
Dialogue: 0,0:02:46.40,0:02:49.61,Default,,0000,0000,0000,,and the fruits of all of that hard labor,
Dialogue: 0,0:02:49.64,0:02:53.64,Default,,0000,0000,0000,,we may want to think about starting\Nto prioritize our sleep some more.