To sleep, perchance to dream - Professor Graham Law from the University of Lincoln comes to SciBar with his talk Sleep Better: The Science of Sleep Myths.
Graham begins with the basics of sleep - it covers all ages, you even sleep in utero and it's a reversible state, we all expect to wake up. While you sleep, you lose your senses as you drift into a lower level of consciousness and physical activity is reduced. There are different cycles to sleep as the night goes on, 2 of non-REM sleep and one of REM (Rapid Eye Movement, where you dream). Despite what you might think, your deepest sleep actually happens in the first few hours and REM sleep is pretty light. Deep sleep is slow wave sleep and people over 80 years old have no detectable deep sleep.
But why do we need to sleep? We don't know! People will say that it's to "recharge the batteries" but you conserve very little energy while sleeping - you only burn off around 100 more calories when lying in front of the TV compared to when you're sleeping. From an evolutionary perspective, sleeping doesn't make sense as it would have made us very vulnerable to predators. A new theory suggests that our brain clears itself of chemicals while we are asleep but all that we can say for certain is that sleep is definitely used to consolidate memories - your short term memories are transferred into your long term memory. Sleep expert William Dement said that we sleep because "we get sleepy".
Sleep is an essential component of life - you can survive without oxygen for minutes, in the elements for hours, without water for days and you will die without sleep in just months. There is a rare disease called Fatal Familial Insomnia that is linked to a genetic mutation. Sufferers dies in a horrible way and many commit suicide rather than die from lack of sleep.
Over the course of his research, Graham has identified 57 different sleep myths, 40 of which are investigated in his book, including the idea that one hours sleep before midnight is worth two after. One of the biggest myths is the "eight hour" myth - even Barack Obama once asked for eight hours sleep for Christmas once. However, everyone needs different amounts of sleep, some will need 7 hours and some will need 9. People can get distressed if they don't get that magical 8 and this can create a spiral where they get even less sleep. Most people need between 6 and 9 hours but some people can get by with even less - you need to get the right amount for you.
Two billion cups of coffee are drank every day on Earth - it is the most widely used stimulant on the planet. Coffee has a half-life of around 6 hours so it stays in your bloodstream for a long time. Hence you need to be careful when you have that last cup of coffee if you want a good night's sleep. On the other hand, studies have shown that the more alcohol you drink, the deeper you can sleep. Many people are clearly using alcohol to bring on sleep but there are obviously other negative factor associated with alcohol use.
There are two systems in your body - sleep pressure (when you feel tired) and circadian rhythms (how your body knows what time of day it is). Light, temperature and even when you eat can affect your circadian rhythm. The cells in our eyes are particularly responsive to blue light, which is prevalent in the light emitted by mobile phones, tablets and LED lights, all of which can help to fool your brain into thinking that it's still daytime. A lot of people, me included, know that feeling where we can't get out of bed and keep hitting the snooze button. This is called "drockling" and can confuse your body because it thinks that it is getting another sleep rather than just nine minutes.
One of the big questions about sleep is about cheese dreams. The British Cheese Board gave 200 people a piece of cheese and then asked them what they dreamed about. Apparently blue cheese gave people surreal dreams while cheddar made people dream about celebrities. Of course, from a scientific perspective, this would go down as one of the worst designed studies ever but it probably helped sell more cheese. Some proper research has shown that people who are more comfortable with themselves are more likely to remember their dreams.
Speaking of dairy, Maggie Thatcher, milk snatcher, claimed that she rarely slept and there seems to be this idea that "sleep is for the weak". However, historically, we used to have two phases of sleep, a "first sleep" and "dead sleep" and this was considered to be quite normal. Of course, this is from a time before we had lights in our homes and so there probably wasn't much else to do other than to sleep. However, naps are good - a nap is around 10-15 minutes, anything longer than that is actually a sleep. We have a circadian dip around 1-2pm, just after lunch and this is the perfect time for a nap.
People with type 2 diabetes often sleep poorly but it’s not yet known which came first - does poor sleep lead to type 2 diabetes or does type 2 diabetes lead to poor sleep? One study has shown that affecting sleep can have an impact on daytime glucose levels. Research has also shown that you shouldn't do high intensity exercise after 7pm.
In the Q and A session, Graham picked up Myth 58 - hypnotists can help you sleep. Graham's book Sleep Better: The Science and the Myths, which examines the first 40 of his myths, is available in all good bookshops.
SciBar will return to The Vat & Fiddle on the 25th of October at 7:30pm.
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