Russell Foster: Why do we sleep? (TED talk)

36% of your life is spent asleep. If you live to 90, that’s 32 years sleeping. This tells us, that at some level, sleep is very important. But many of us just don’t think seriously enough about sleep.

We’ve begun to treat sleep as an enemy. We tolerate it, but we don’t care much for it. How come? It’s because we don’t do a lot when we’re asleep. We are totally unproductive.

But now neuroscientists are starting to understand why sleep is so important to us. There isn’t a clear consensus, but three theories stand out:

  • Restoration. All the stuff we burn up during the day, we rebuild during the night. It’s been shown that only some genes are turned-on during sleep, and those genes are associated with restoration.
  • Energy conservation. You sleep to save calories. But the amount of calories you actually save during sleep is so low, that it seems like a less plausible explanation.
  • Brain processing and memory consolidation. We know that when somebody tries to learn a new task, and then you sleep deprive them, you smash this learning process. Sleeping at night can give up to 3x boost in creative thinking. It’s core to our learning ability.

What’s so interesting about our society today is that we are desperately deprived of sleep, and it’s been gradually getting worse.

If you sleep 5 hours or less a night, you have a 50% increased likelihood of being obese. Sleep loss promotes a gene which makes you need to eat more.

Lack of sleep brings on increased stress. And prolonged stress is a very bad thing – studies show that stress weakens your immune system to infections, and even increases your risk of cancer.

How do you know if you’re getting enough sleep? Well, do you need an alarm clock to wake you up? Do you need stimulants to feel better in the morning?

How to improve things? First thing is to make your bedroom a sleep haven – make it as dark as you possibly can, and try to make it slightly cool. Decrease your exposure to light in the 30 minutes before sleep – this can be tricky when you have bright lights in your bathroom. Try to avoid caffeine after lunch.

Teenagers are often called lazy – but really they aren’t. They have a biological disposition to go to bed late, and get up late. Give them a break!

We need eight hours of sleep a night, as an average. Do you need that much, or do you need more? You need to listen to your body, and figure it out. There is no universal answer.

They say that people who go to bed early and get up early are wealthier, more prosperous. But there’s no evidence for it – they just seem to be more smug than anyone else.

Recent studies have shown a clear link between mental illness and lack of sleep. Sleep can act as an early warning signal for mental health problems.

Bottom line: take sleep seriously. It’s intimately linked to well being.

(Part of TED a day for June)


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