by Gord Grant PhD, RAc
Russell Foster did a TED talk on sleep entitled “Why do we sleep?”. He says that in the past eras, sleep was welcomed and understood as a necessary cycle in our lives. In recent times since industrialization, the fact that we spend about 1/3 of our lives asleep is a problem –sleep has become a foe! Foster reflects that this sentiment has been summed up by people like Thomas Edison (“Sleep is a criminal waste of time and a heritage from our cave days.”), and Margaret Thatcher (“Sleep is for wimps.”).
As a neuroscientist, Foster supports what he feels are the two best theories for why we need sleep. Firstly, we sleep for physical restoration where the body’s metabolism changes gears — doesn’t necessary slow down all that much, but rather changes to repairing and restoring and maintenance functions. Perhaps even more important, during sleep the brain undergoes a process of filtering and memory consolidation.
Sleep-deprived individuals have a greatly reduced ability to learn a new task, or laying down a memory and being able to later recall it. What’s even more affected by sleep though is our creativity – if we are sleep deprived we are much less able to come up with novel solutions to complex problems. Foster says research shows that we can have as much three fold improvement in creative thinking after a good sleep! We all know we come up with better solutions to a problem or a difficult situation after a good sleep. Isn’t that where the saying “sleep on it” comes from?
Foster describes how sleep deprivation is strongly correlated to obesity, and may be because the stress of being sleep-deprived causes increased levels in the body of the hormones cortisol and grehlin. Cortisol is a longer term stress hormone which induces adaptive metabolic shifts in the body, including the storage of abdominal fat. Grehlin is the hunger hormone and can be associated with an increased appetite.
What makes things worse, is the viscous cycle many create in trying to cope. Many use stimulants like coffee to keep awake after sleeping poorly – this then causes them to have a bad night sleep the next night. The caffeine in coffee is actually a drug that blocks the sleep signal the brain sends to the sleep centre. So it is not really a true stimulant, but is a sleep-blocker! And so then the cycle can continue with the use of depressants in the evening to get to sleep after using excess stimulants. People often drink alcohol before bed to wind down and then get to sleep. Or some use sleeping pills. Regardless, the problem with depressants is that they interfere with active nature of the brain at sleep that is sorting things out from the wakeful experience. Yes, depressants can get you to sleep, but they diminishes the quality of sleep by inhibiting mental consolidation. And so, exhausted, the need for morning time stimulants continues!
Foster says that research from the 1950s showed most of us were getting around about eight hours of sleep a night. Nowadays, were are down to six-and-a-half-hours every night. For teenagers, even though most need nine hours for full brain performance, many of them on a school night are only getting five hours of sleep! A rule of thumb to know if you are getting enough nourishing sleep is in how you use an alarm clock. If you need an alarm clock to wake up in the morning (not just as a backup in case you don’t), then likely you are not getting enough sleep.