Neuroscientist Dr. Matt Walker explains that people who believe they function well on six hours of sleep typically suffer hidden deficits in other physiological domains.
Insight
Walker: Morning coffee's immediate wakefulness comes from drink temperature, not caffeine
“They say within a couple of minutes, you know, five minutes later, oh gosh, you know, I feel so much better. All right. I'm ready to face the world. And you think that that's the caffeine. That's nonsense. The caffeine isn't probably, you know, working within …”
Insight
Walker: Falling asleep immediately is a sign of accrued sleep debt
“Sleep is not like a light switch. Sleep is much more like landing a plane, that it takes time for you to descend down onto the terra firma of healthy, good sleep at night. And the reason I'm nervous when people say, look, I get into bed and I, you know, as soo…”
Assertion Partly supported
Walker: Sleep Loss Doubles Risk for Specific Cancers, Not All Cancers
“A lack of sleep can double your risk for Certain forms of cancer, and then name those cancers, and those, for example those cancers would be thyroid cancer, lung cancer, ovarian cancer myeloma, which is a form of a blood cancer linked to, it's in the ilk of so…”
Assertion Partly supported
Walker: Being struck by lightning is more likely than being a genetic short sleeper
“Statistically, you're far more likely to be, for example, struck by lightning in your lifetime than you are to be one of those genetic short sleepers. The lifetime odds of being struck by lightning is one in 12,000, just if anyone, if anyone's interested.”
Assertion Supported
Walker: Average US sleep dropped from 7.9 hours in 1942 to 6.5 hours
“There was a Gallup poll that was performed back in 1941 or 1940, I think it was 1942, sorry. And what they found was that On average the human adults in that survey reported sleeping 7.9 hours a night on average. But now, based on data from the National Sleep …”
Assertion Supported
Walker: Evening coffee can cut deep sleep by 20% to 40%
“What you don't realize is that caffeine can actually decrease the amount of deep sleep that you're getting, stages three and four. And in fact, what we found is that even just one to two cups of coffee in the early or late evening can decrease the amount of yo…”