With increasing workloads and a million other stuff that needs to be done getting enough sleep can seem like it’s not that big a priority. You may have been told growing up that sleeping can help your body recuperate from the day’s activities but with only 50 kcal of energy being saved in eight hours sleep (that’s about the same as a piece of toast) that doesn’t seem to be the case. So why is sleep so important?
When you are awake your body creates a chemical called adenosine and then breaks it down when you are asleep. If you do not get enough sleep it can build up in your blood stream leading to some potentially dangerous side effects.
Studies have shown sleep is needed to maintain cognitive functions, such as speech, memory, innovative and flexible thinking. Staying awake for 17 hours has the same effect as a blood alcohol level of 0.05% (legal drink driving level in UK).
With sufficient lack of sleep the part of the brain that controls memory, language, planning and sense of time effectively shuts down. Sleep deprived individuals have more difficulty responding to rapidly changing situations and making rational decisions. This is believed to be a factor in many disasters including Chernobyl.
Sleep also has an impact on physical, emotional and mental health. According to a study by the National Sleep Foundation, teens who don’t get enough sleep are more inclined to be stressed and irritable, prone to skin problems (such as acne), change in diet (eating more or eating more sweets and fizzy drinks) and aggressive or inappropriate behaviour towards friends and family. People who are not getting enough sleep can also be more impatient and forget important names, dates and numbers. On a physical level people suffering from sleep deprivation are more likely to suffer from illnesses or get into accidents.
But what happens when we sleep?
There are four stages of sleep which we go through in a cycle. The first stage is light sleep, when the body is half asleep and half awake, and lasts about ten minutes. Muscle activity slows down but it is still easy to wake up someone in light sleep.
Stage two is true sleep. True sleep makes up a large part of human sleep and lasts for approximately 20 minutes after light sleep. Breathing patterns and heart rate both slow down.
Stages three and four are deep sleep. During stage three the brain produces high amplitude, low frequency delta waves. Breathing and heart rate are at their lowest levels. Stage four is characterised by rhythmic breathing and limited muscle movement. Waking up in this stage can leave you groggy and disoriented as it can take some time to adjust.
Three to five times a night you go through the REM period of sleep. During the REM (or rapid eye movement) period the brain is very active – sometimes more than during the day – and dreams often occur. Eyes dart around behind eyelids and breathing rate and blood pressure rise however the body is effectively paralysed. Scientists believe this is to stop us acting out our dreams as we sleep.
REM begins around 90 minutes after falling asleep and once it is over the cycle is repeated.
This chart shows the amount of sleep each age group requires and what may be appropriate if that isn’t possible.
Getting enough sleep is essential and it is estimated a shortage of sleep was responsible for 100000 traffic accidents, 76000 injuries and 1500 deaths a year in the USA. If you don’t get enough sleep you can go into sleep debt. For more information on sleep debt and how to cut down on it, follow the link to the sleep foundation website: click here.