THERE is an old Irish saying: "A good laugh and a long sleep are the best cures in the doctor's book."
Sleeping is a basic human need, just like breathing, eating and drinking. Yet many of us consider sleep a luxury.
How does sleep help keep us well? Did you know that all proteins in our body are synthesised when we sleep?
Tissue and muscle growth and repair, as well as hormone and enzyme synthesis, occur almost exclusively during sleep.
There are several damaging effects of a lack of sleep.
FIRST, there is poor growth and development.
For examples, in growing children and adolescents, sleep helps the manufacture of proteins that promote the growth of muscle and bone, repair cells and tissues, and manufacture fertility hormones.
A lack of sleep causes growth retardation and mental and emotional stunting.
SECOND, a lack of sleep induces obesity. Our body produces the appetite hormone, ghrelin, and the satiety hormone, leptin, when we sleep.
Lack of sleep makes our ghrelin levels high and leptin levels low. Why our body is so contrary, we don't know.
THIRD, heart problems result from sleep deprivation. Blood pressure normally reduces during sleep, along with the heart rate. Less sleep can lead to a higher average blood pressure, which increases our risk of heart disease and stroke.
Additionally, long-term sleep lack can lead to a low-level inflammatory state in our body, which leads to heart disease, dementia and even cancer.
FOURTH, glucose management is affected when our sleep is inadequate. Insulin is a hormone that helps our cells to use blood glucose to make energy.
Sleep deprivation causes the cells in our liver and muscles to not recognise insulin, and so they are unable to use glucose, making our blood sugar high.
FIFTH, sleep enables new immune cells and proteins (immunoglobulins) to be manufactured.
Lack of sleep reduces the immune cells' ability to destroy old and damaged cells, leading to poor immunity against infections, as well as increased auto-immune diseases or cancer.
SIXTH, all the brainstorming when awake creates harmful waste matter that sit in the nooks and crannies of our brain.
When we sleep, these toxic chemicals are broken down and washed away, and new brain chemicals are produced, ready to allow our brain cells to talk to each other when we wake up.
So a good night's sleep improves our ability to concentrate, be creative and learn new things.
Bad news for all you workaholics who are planning to trade a night's sleep for work. We can also consolidate our memory by daytime naps.
SEVENTH, poor sleep can make us grumpy and irritable, preventing us from making good decisions, and coping with the stresses of life.
Sleep deficiency can lead to mental health issues, like depression, increased suicide risk, bipolar disorder, mania and post-traumatic stress disorder. Additionally, sleep deficiency also raises the risk of workplace and road accidents.
How much sleep do we need? The American Academy of Sleep Medicine made these recommendations:
6 to 12 years: nine to 12 hours
13 to 18 years: eight to 10 hours
18 to 64 years: seven-plus hours
65+ years: seven to eight hours
We can treat sleep deprivation in the following ways: not sleeping in when we aren't sleepy; going to bed around the same time each night; being more physically active during the day; reducing stress through exercise, therapy or meditation; and not relying on sleep medication.
Long-term use of sleeping pills can lead to dependence.
William Shakespeare describes the blessings of sleep so well when the tormented Lady Macbeth says: "Innocent sleep. Sleep that soothes away all our worries.
"Sleep that puts each day to rest. Sleep that relieves the weary labourer and heals hurt minds. Sleep, the main course in life's feast, and the most nourishing."
Sleep well, dear reader. Your body will thank you for it.
The writer is a deputy director of the Clinical Skills Centre, Faculty of Medicine, AIMST University