Is six hours enough, and can you recover from years of short sleep?
In live Q&As and with Walker, Huberman takes up how much sleep individuals really need, whether lost sleep can be made up and what improves after years of short nights. The answers replace a single eight-hour rule with a way to judge personal need.
Is six hours of sleep enough, according to Huberman? Show answer
It depends on the person. If you feel good and have energy and focus through the day, he would not worry, though his goal for most people is at least six and ideally seven or eight.
How much sleep does Matthew Walker say most adults need? Show answer
Seven to nine hours. He adds that on average people probably need about 90 minutes more than they get.
What does QQRT stand for? Show answer
Quantity, quality, regularity and timing. It is Walker's four-part test for judging your sleep, which Huberman also uses.
What counts as healthy sleep quality in Walker's terms? Show answer
Sleep efficiency of 85 percent or more, meaning that share of your time in bed is spent asleep.
What did a week of six-hour nights do in the University of Surrey study Walker cites? Show answer
It changed the activity of 711 genes, turning down immune genes and turning up genes linked to tumors, inflammation and cardiovascular stress.
Why does getting up two hours early cost more than it seems? Show answer
REM sleep is concentrated late in the night. Losing the last two of eight hours removes 25 percent of sleep but perhaps 60 to 80 percent of REM.
Can you recover from years of short sleep, according to Huberman? Show answer
Yes. He says the brain can recover and substantial damage is unlikely, unless you did it your whole life and only address it late.
What is Walker's objection to judging sleep by how you feel? Show answer
A key danger of sleep loss is that you do not realize how impaired you are, much like a drunk driver.
What daytime checks does Walker suggest? Show answer
Ask whether you would sleep past your alarm, whether you can function with good mood and clear thinking before 11 a.m. without caffeine, and whether you have lapses of attention.
Where do Huberman and Walker disagree about non-sleep deep rest? Show answer
Huberman thinks 10 to 30 minutes of it can restore some of what a short night takes. Walker does not accept it as a replacement for sleep.
What is Huberman's advice for shift workers? Show answer
Keep the same sleep-wake schedule for at least two weeks at a time and get whatever sleep you can. Constantly swinging shifts are the worst.
Which regularity finding does Walker cite from the UK Biobank study? Show answer
The most regular sleepers had a 49 percent lower risk of dying from any cause than the most irregular, and regularity predicted mortality more strongly than duration.