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  • Writer's pictureMollie Maxwell

The benefits of a good night's sleep

Sleep hygiene is an undervalued necessity.

Sleep basics are about 14-17 hours a day for babies, decreasing over time to an optimum of 7-9 hours for adults. By depriving ourselves of sleep we increase the mortality rate , our neurological and neuromuscular behaviour decreases with lack of sleep which has a similar effect to driving drunk. About a third of the population get less than 6 hours sleep a night and 4 % of the population might be taking sleeping medication.

Chronobiology. The biology of sleep cycles.

The Circadian rhythm shows that during night time sleep we have deep sleep first and REM sleep later in the night . The Circadian rhythm covers full 24 hours The Ultradian rhythm is cycling every 90 minutes or so with a period of good concentration followed by a healing response. this is why we can concentrate really hard on something for a period of time and then we tire and our concentration lapses.


LARKS . Mainly early risers and early to bed . Elderly often fit into this chronotype

NIGHT OWLS . Sleepy in the mornings, hard to wake up and often late to bed. Typical behaviour seen in teenagers.

The nasal rhythm is an unconscious blocking and unblocking of nostrils during the day according to the ultradian rhythm. It allows one nostril to work really efficiently while the other side rests although it is not normally noticeable. Nose breathing is really important because it cleans the air we breathe and filters out the bugs. It also helps with releasing nitrous oxide, increases vasodilation, lowers the heat rate, turns off the sympathetic nervous system ( fight or flight ) . A good restorative sleep releases growth hormone .

Sleep cycles:

Deep sleep dominates the sleep pattern, synaptic pruning goes on, clearing out waste that is no longer needed, the memories and experiences during the day are filed away in the appropriate part of the brain and the Hippocampus is cleared, ready for the next day. Brief periods of dreaming occur within this sleep . The last 20 % of sleep is dream and REM sleep which is where creative solutions occur . During REM sleep you are limp and unable to move.

Animals can use half their brain for sleeping and the other half and one eye is on guard duty. Seals do this in the ocean but on land can sleep fully. Birds on their own do half sleeping but in a flock can fully sleep with one or two birds on lookout duty.

When we sleep in our own beds, we can sleep deeply but in a new bed or environment we may keep one hemisphere of the brain awake to guard for danger. This is why we often sleep less well when away from home

Foetuses engage in deep and non REM sleep as well as REM sleep. This can be affected by maternal alcohol drinking and why avoiding alcohol is important during pregnancy. The foetus spends 21 hours a day sleeping and has not developed the inability to move while in REM which is often then they are kicking because they can't control their movements. It takes babies about 6 months to develop a Circadian rhythm. Teenagers increase their deep non REM sleep because they are refining their brains and adapting to life.

Sunlight and Melatonin - a hormone that is suppressed during the day especially in blue wave light and as twilight approaches the blue light decrease and Melatonin is released. Cortisol and Melatonin work antagonistically. Our melatonin degrades as we get older, which is why we might might sleep less as we age,

Adenosine - a neurotransmitter that rises during the day and is cleared out after good sleep. Coffee blocks adenosine in the brain. Adenosine production increase the pressure to go to sleep and is highest at around 11pm and lowest at 7am.

Napping reduces sleep pressure and also Adenosine which is why it may be beneficial for cardiac risk . If you go 24 hours without sleep Adenosine continues to accumulate .

LED lighting is very high in blue light and may even be more concentrated than the blue light from sunlight. The overuse of LED blue light upsets the Circadian rhythm and close to bed time this blue light suppresses Melatonin much more in children and young adults and affects the quality of sleep as well as the quantity .

Sleep hygiene, the practices than help you to get a good sleep.

  1. Get into routine of rising and sleeping at around the same time and avoid social jet lag. Shift work negatively impacts the quality of life and cannot be caught up with by a single good sleep. High BP, high cholesterol and depression disrupts the circadian rhythm and is difficult to recover from

  2. Keep the bedroom cool, dark and quiet. Peripheral limbs being kept cool encourages melatonin production.

  3. Avoid caffeine, sugar and carbohydrates before bed. Fatty foods are better nearer bedtime as they do no suppress melatonin .

  4. Keep screens and devices out of the bedroom

  5. Get lots of sunlight during the day to assist the Circadian rhythm

  6. Avoid alcohol which disrupts sleep and makes you want to pee. It cancels deep sleep and REM sleep, reduces neuroplasticity . Alcohol in pregancy dials down the foetus’s cognitive development

  7. Being active and taking vigorous exercise during the day helps you to feel physically tired

Short naps during the day of around ten minute reduces heart attacks by 37 %. More people have heart attacks when the clocks go forward and less then the clocks go back showing that one hour less sleep has a huge effect.

Sleep issues;

Approx 1/3 of the population get 6 hours of sleep or less or they don’t wake up feeling refreshed, they wake in the night and cant get back to sleep.

Why do they sleep so badly ?

30-40 % have stress or mental disorders

5-9 % have breathing disorders

10% have restless leg syndrome

4-11% have medical neurological conditions

10% poor sleep hygiene or environmental factors

3-7 % psychoactive substances

12-16%. No identifiable cause

Snoring and sleep apnoea is suffered more by men and Maori

Sleep disordered breathing SDB/Apnoea. Is primarily caused by obesity. Breathing stops and starts again often because of the weight of the chest.

In snorers, large tongues can cause vibrating. The tongue being the first organ to accumulate fat. Reducing weight often helps. Sometimes snoring occurs in the nose and training for nasal breathing can help this.

Sleep apnoea is aided with a CPAP machine. Continuous positive airway pressure can be very successful and it prevents frequent waking and encourages deep and REM sleep.

Insomnia is a common issue, some of which may be due to poor sleep hygiene, some is a biological problem and sleeping tablets may not be of much help. Cognitive behavioural therapy may help by reducing negative thinking

Restless leg syndrome also known as periodic limb movement causing hot, quivering and itchy feet or legs in 10 % of the population. Intake of sugar, caffeine and alcohol can aggravate this .

Because of the debilitating effect of poor sleep or lack of sleep, it should be addressed by a medical professional and often it can be eased by various methods. If you have a problem with sleeping, talk to your Doctor and ask for referral to a sleep clinic.


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