Sleep is easy right? Wrong! There are many different factors that affect our sleep patterns; our ability to go to sleep, stay asleep or wake up all impact on how we manage our daily lives.
So let’s get to grips with sleep. Sleep is controlled by two factors; the Circadian Rhythm and Sleep Drive.
The Circadian rhythm is the natural physical, mental and behavioural changes that our bodies make in response to light and dark and the natural 24 hours cycle. Circadian rhythms are controlled by a biological clock located in the brain, e.g. during the night our bodies boost the production of melatonin and then reduce it once it is daylight.
Sleep drive is a natural instinct, much as your body craves food when it is hungry, your body craves sleep when you are tired. The Sleep Drive becomes more insistent throughout the day and we naturally crave sleep more the later it gets. The big difference between hunger and sleep is that we can choose not to eat; when you are tired your body will ‘put you to sleep’ wherever you are, whatever you are doing. This is why it is so important not to drive when tired. It is possible for your body to engage in microsleep episodes with your eyes open; these may only last for a few seconds but imagine if you were behind the wheel of your car.
Key Point to remember: Napping is useful but more than 30 minutes can disrupt you sleep later by confusing your bodies sleep drive.
We have all had those nights where sleep eludes us and we get up feeling exhausted and not quite ‘with it!’
Sleep is a vital function to maintain the brain’s plasticity or it’s ability to take in and process information. Too little sleep and we can’t process what we have learned during the day and it will be much harder to remember it in the future. Sleep also helps to clear ‘waste’ products form brain cells.
Sleep is also vital to the rest of the body, maintaining and repairing.
Whilst you are asleep your brain is like a giant post office, sorting and storing what you have learned during the day. This is particularly important for creating long term memories.
Whilst you are asleep your body has chance to rest and repair it’s systems. To do this your body releases hormones, all of which have specific jobs, e.g. melatonin is released at night by your pineal gland; this makes you feel sleepy and controls your sleeping patterns. Growth hormones are released by your pituitary gland to repair musco-skeletal damage and promote growth.
Your sympathetic nervous system controls your flight, fight or freeze response and is always on alert for percieved threats or danger. Nightime is the time is gets a chance to stand down and relax. Sleep deprivation can increase the activity of the sympathetic nervous system, raising blood pressure, causing anxiety and exhaustion.
Cortisol is the ‘stress hormone’ and this is what keeps us alert at times of extreme stress. It also has a regulatory role; cortisol levels decrease rapidly during the first few hours of sleep. As we wake our cortisol levels rise to a peak, making you feel perky when you wake up and hungry.
During sleep everyone cycles through the various stages of sleep several times in a night, REM and Non-REM. During REM we have the most vivid dreams. At this time your muscles are paralysed, and scientists believe this is to keep us from acting out our dreams physically and thus keeps us safe.
During the day you might go to the loo every 5 minutes, but miraculously you only go once in EIGHT hours of sleep! How is that even possible.
Two considerations; when you are asleep you are not drinking, therefore reducing fluid intake.
Secondly the Circadian Rhythm causes the body to release a hormone called ADH, Anti-diuretic Hormone. This is a pee blocker; during the night ADH released by the brain tells the body to pee less during the night.
Sleep is a booster for your immune system. Your immune system produces a type of proteins called cytokines. These help your body to fight injury, infection, inflammation and trauma.
So whilst you are asleep your body and brain are working hard to process, sort and store data, repair and maintain the body and boost our immune systems and whole heap of other good stuff. Seems to be that sleep is more important than you might have imagined.
It is estimated almost 30% of the adult population are affected by sleep problems. Some are very common and are often referred to as insomnia. Sleep problems are particularly common in women, children and older people, aged 65 plus, roughly half of the older population complain of insomnia.
There is no ‘normal’ amount of sleep, everyone is different. The popular idea is that we all need our ‘8 hours a night’, but this is just not true.
Studies indicate that sleep requirements can range from 4 – 10+ hours a night. The amount of sleep we need is influenced by lots of factors;
At least 5 different types or stages of sleep have been identified; sleep is not like a light bulb, either on or off, but has different stages, varying from light to deep sleep.
Very broadly sleep is divided into REM (Rapid Eye Movement) and Non REM sleep.
REM sleep happens several times a night, and is where most of the dreaming occurs. Non REM sleep is divided into four key stages, each stage being a bit deeper, almost like a stairway to sleep.
During the night people will go up and down this process several times and may wake up a few times.
On a typical night a young adult who sleeps well will spend about 5% in stage 1, 50% in stage 2, 28% in deep sleep, stages 3 & 4 and about 25% in REM sleep.
For someone who is in the 65+ age group deep sleep takes up less than 10% of the night’s sleep.
Knowing the sort of sleep problem you have can help you to manage it better and put some sleep hygiene measures in place.
Think about a typical night’s sleep and consider which of the following statements apply to you:
Getting to sleep: This is probably the most common sleep problem; for some people it can take several hours to drop off to sleep, but once asleep the quality of sleep is good.
Staying asleep: The next most common problem is disturbed sleep patterns, with frequent waking the middle of the night and difficulty getting back to sleep.
Waking too early: Waking earlier than desired is a third problem, again with difficulty getting back to sleep.
Poor quality sleep: In addition to the above some people report sleeping lightly, with restless, disturbed and inconsistent sleep.
In Summary: Sleep problems are not uncommon and affect everyone differently. There is no ‘right’ amount of sleep as this varies between people and is affected by both internal and external factors; age, medical reasons, emotional impact, environment. There are different sorts of sleep problems and these can be addressed with a range of sleep hygiene tools.