Contrary to what you might think, when you sleep your body is not truly ‘resting’.
During the two main phases of sleep – REM and non-REM – your body is by turns sorting out memories and repairing tissue damage. These phases cycle every 90 minutes throughout your slumber.
We dream during REM, or the rapid eye movement phase, so named because our eyes appear to move quickly behind our closed lids. And even though we are lying still, our pulse, blood pressure, breathing and body temperature are the same as during the day.
In non-REM sleep, the reverse happens as our body temperature falls and breathing slows down. Our pulse and blood pressure also lower, giving our circulatory system the opportunity to rest and recover.
In the last stage of non-REM, sleep becomes the deepest and this is when tissue repair happens as immune-boosting chemicals circulate in your blood.
The older we become the less time we spend in non-REM sleep and by the time we reach 65, we may not be getting any of this sleep at all.
REM phases are when our brains sort through information we have ‘collected’, file it away in memories and prepare it for the next day’s cognitive functions.
During the REM dreaming stage, the brain stem sends signals to temporarily paralyse some of the muscles in our body. It is believed that this is to stop us from acting out our dreams.
The elevation and suppression of different hormones also occur as we sleep. Growth hormones increase and these are believed to help with tissue repair. Cortisol, the ‘flight or fight’ hormone, lowers at the start of sleep before building back up, to make sure we wake up alert.
Getting enough shut-eye is important for health. If you are sleep deprived, chances are you are not giving your body and mind the opportunity to regenerate and face the day as best you can.
Do you get enough sleep? How many hours of sleep do you think is enough for you? What tips do you have for good hygiene?
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