The Ledger
Every statement that passed quotation and attribution checks. Mix any filter with any other: certainty 1/5, debate potential 5/5, or both at once.
why aren't all 19 resolved? a statement only gets an assessment when the public record can support or contradict it. opinions and what-ifs never can, and 0 checkable ones are still open, waiting for their date. predictions held up or didn't; assertions are supported or contradicted. on every card: ▮▮▮▮▮ certainty · ▮▮▮▮▮ debate potential. speakers are clickable
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 …”
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…”
Walker: Falsely telling people they slept poorly degrades cognitive performance
“And then you have them perform a set of tests, and lo and behold, despite both groups having, on average, about the same amount of sleep, the group that was psychologically informed as to having insufficient sleep performs insufficiently on the cognitive level…”
Walker: Sleeping under seven hours causes measurable cognitive and bodily impairments
“What we found is that once you drop below seven hours of sleep, for most people, we can measure objective impairments in either your brain and your body.”
Walker: Habitual 7.3-hour sleepers stabilized at 8.5 hours in sleep experiment
“They were sleeping about 7.3 hours every night, and they said subjectively, I feel fine. I feel well rested. So then they brought them into the laboratory for eight nights straight, And then they gave them an extended amount of time in bed. I think it was almo…”
Walker: Coffee's health benefits come from antioxidants, not caffeine
“The reason that coffee provides those health benefits is not because of the caffeine. It's because the coffee bean provides, for most people, because our diets are not really very good, the standard American diet, for example isn't ideal in its nutritional pro…”
Walker: Coffee health benefits turn negative past 3 to 4 cups daily
“Once you get past about three or four cups of coffee a day, then the health benefits start to go in the opposite direction. It starts to become a negative trending direction in terms of health, but also in terms of sleep too.”
Walker: Peak testosterone release occurs during REM sleep, not exercise
“And we produce our peak levels of testosterone release, not during the day, or even after the gym, or just as we're working out during the gym, we produce our peak levels during REM sleep, just before and throughout that period of REM sleep.”
Walker: Evening alcohol consumption cuts nighttime growth hormone by 50%
“In fact, there was a frightening study that demonstrated that a couple of doses of alcohol in the evening, sort of getting you, not really tipsy, but kind of close to that, resulted in a 50% five-zero decrease in growth hormone at night.”
Walker: Even one evening glass of wine measurably impairs sleep
“We found that even just one glass of wine in the evening can have, you know, significant and measurable impacts on your sleep at night”
Walker: CBT-I matches sleeping pills short-term and yields lasting benefits
“I mentioned that technique called, that therapy called cognitive behavioral therapy for insomnia, and it is just as effective as sleeping pills in the short term, but what's better is that once you stop working with your therapist, once you stop engaging with …”
Walker: Sleep shifts from deep non-REM early on to REM later
“So that in the first half of the night, the majority of those 90 minute cycles is going to be comprised of mostly deep non-REM sleep, stages three and four. But as we push through to the second half of the night, now that seesaw balance actually shifts over, a…”
Walker: Optimal sleep comprises 20-25% REM and 20-30% deep non-REM
“For most of us, we should spend probably about 20 to 25% of the night in REM sleep, about 20 to maybe 30% of the night in deep non-REM sleep, and the rest is light non-REM sleep.”
Walker: Caffeine has a 5 to 6-hour half-life
“Caffeine has a half-life of probably around five to six hours. In other words, after five to six hours, 50% of that caffeine is still in your system, half of that caffeine, hence half-life. Which means that after two 10 to 12 hours, there's about a quarter of …”
Walker: Alcohol consumption blocks rapid eye movement sleep
“The third of the four problems with alcohol and sleep is that it will block your rapid eye movement sleep or your dream sleep.”
Walker: Insomnia is approximately 30% genetically heritable
“Firstly, there is some genetic heritability to it. It seems to be that insomnia is about 30% Heritable.”
Walker: ACP recommends CBT-I as frontline chronic insomnia treatment
“In 2016, the American College of Physicians made a landmark
statement.
They said, based on reviewing the evidence from sleeping pills and their minimal effective use for insomnia,
Their first line recommended treatment for all people with chronic insomnia sho…”
Walker: Sleep onset requires dropping core body temperature by one degree Celsius
“So what we know is that for you to fall asleep and for you to stay asleep across the night, your body and your brain need to drop their core temperature by Probably almost about one degree Celsius across the entire night from its extremity from the highest poi…”