Sleep is a trending topic at the moment – and it seems that the whole world is waking up to recognise the importance of sleep. Sleep is essential for human survival, and good sleep is necessary to be able to enjoy good physical health and mental health. It’s a very current topic, as 30% of people do not get sufficient sleep.
Why is sleep important?
Whilst we are able to tolerate short periods of poor sleep, and even longer periods at certain stages in life – after having a baby for example, chronic sleep deprivation throughout our lives is bad news. Sleep is extremely important for brain function and that includes our mental health, and also impacts our social lives too, from relationships and productivity to sex drive and alcohol use. This is all down to the complex, and essential processes that take place during sleep, ranging from cell repair and immune system optimisation to emotional regulation, and not to forget (no pun intended) that it’s during sleep that we form memories and process what we have learnt in the day.
The Stages of Sleeping
When you sleep your body cycles through 4 different stages. Not all sleep cycles are the same length, but on average they last about 90 minutes each. The typical adult, who is getting the recommended 7-9 hours, will go through four to six full sleep cycles each night.
Stage 1, is the slowing down and “dozing off” stage, and it normally lasts just one to five minutes. During this stage someone is easily rousable, they may twitch and keep hold of a book resting in their hands for example.
Stage 2, brain activity slows, eye movements stop, breathing and pulse rate slow, muscles relax and body temperature lowers. This stage last around 10-25 minutes.
(If you like to take a daytime nap you should aim to complete your nap before entering stage 3, this will allow you to gain the refreshing benefits of a nap, without the groggy sleepy feeling)
Stage 3, is the deep sleep stage. The body relaxes and slows further, and it’s much more difficult to rouse somebody. This is thought to be the ‘restorative’ phase when the body’s cells undergo repair, the immune system is enhanced, and the body develops. It’s important for brain function too, especially for mood, creativity, storing of information and memories. You spend 20-40 minutes in this stage early in the night, but as you go through the night the length of time spent in this stage shortens, and you tend to spend more time, per cycle in stage 4, If you are woken during deep sleep then you’re likely to feel groggy and unrefreshed.
REM sleep is the final stage, REM stands for rapid eye movement. If you look at someone sleeping, during this stage, you can see their eyes moving underneath their eyelids. This is where brain activity picks up again and when the most vivid dreaming occurs. Whilst the eyes are moving there is temporary paralysis of most muscles – an important factor that stops you from acting out your dreams. Breathing and heart rate are quicker, and men may experience penile erections. REM sleep is thought to be essential for learning, memory and creativity. As the night goes on we spend more time, per cycle, in REM sleep. So in the first cycle it can be just a few minutes, and closer to an hour by the final cycle.
How Many Hours of Sleep Do You Need?
For children ages 6 to 12, the NHS recommends between 9 to 12 hours of sleep each night. For younger children, more than 10 hours of sleep each night are recommended.
It is a common misconception that older adults need less sleep than when they were younger. Many older adults have a hard time getting , but that does not mean they need less sleep. In general, most adults should aim to get between seven and nine hours of sleep each night. It is true, though, that as we get older we tend to go to sleep earlier and get up earlier than we used to. This is due to changes in our body’s circadian rhythm (internal clock), that actually shift forward in time as we get older. The part of the brain that controls our body clock receives information from the eyes, and light is one of the most powerful cues for maintaining circadian rhythms. Therefore, ensuring that we are exposed to sufficient amounts of natural daylight during the day is really important. Spending time outdoors, whether a lovely long walk in the park, or even if it is just standing on the doorstep is an important regulator of sleep.
Other sleep thieves include chronic diseases, pain, needing to pee during the night, and medication – all of which are more likely as we get older. Almost 40% of adults over the age of 65 take five or more medications.
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