7. Dreaming is like overnight therapy
Dr Walker describes dream sleep, or REM sleep, as “overnight therapy. That dream sleep is essentially emotional first aid.” It’s your mind’s time for processing tough things you’re going through, in a soothing way. “It takes the sharp edges off those difficult experiences so that the next day when you wake up they don’t feel as bad anymore… It’s a pair of emotional windscreen wipers, so everything gets cleared out by the next morning.” If you feel irritable or anxious after a bad night’s sleep, part of it is because you lacked that vital REM sleep.
8. A lunchtime coffee could spoil your sleep
Everyone knows caffeine and alcohol affect sleep, but maybe not how significant the effect. “Caffeine has a half-life of five to six hours, which means it has a quarter-life of 10-12 hours,” says Dr Walker. “In other words, after 10-12 hours, a quarter of that caffeine you had is still in your brain. So having a coffee at noon is the equivalent of getting into bed and, just before you turn the light out, swigging a quarter of a cup of coffee.” Even if you’re someone who thinks they can drink coffee at night and still sleep, you’re partly wrong. “Even if that’s true, the amount of deep sleep you get is reduced by 20%”. Alcohol is equally bad for sleep. Even if it helps you nod off, it’s not helping you sleep. “Alcohol is a sedative… and sedation isn’t sleep.”
9. Set a routine to get better sleep
Now we know the bad effects of too little sleep, how do we get more of it? Dr Walker says routine is vital. He calls a good sleep routine “an investment in tomorrow”. He says setting a regular bedtime and wake-up time, even on weekends, is essential. “Your brain has a 24-hour clock embedded inside it. It works best under conditions of regularity.” He even suggests setting an alarm to tell you when to go to bed. You should also keep your bedroom cool because your body has to drop its core temperature by one degree Celsius to fall asleep. Make sure your room is dark. And don’t stay in bed if you can’t sleep. “[If you lie awake] your brain quickly learns that every time you get into bed it’s the place where you’re awake. You need to retrain it to say, ‘Every time I’m in bed, I’m asleep.’ If you’re awake for 25-30 minutes… get up, listen to a podcast, or read or something. Only when you’re sleepy should you go back to bed… You’d never sit at a dinner table waiting to get hungry, so why would you lie in bed waiting to get sleepy?”