Lack of sleep can cause people to suffer fatigue, poor concentration, memory problems, mood disturbances, impaired judgment and slower reaction time.
The brain moves from light sleep to deeper sleep - and eventually moves to rapid eye movement, or REM, sleep.
The four stages of non-REM sleep
Stage 1. Dozing or drowsiness. Sleepers hover between being asleep and awake.
Stage 2. The moment of falling asleep. Sleepers lose awareness of their surroundings. Body temperature starts to drop. Breathing and heart rate slow down.
Stage 3. Deep sleep, also known as delta sleep. Sleepers blood pressure, heart rate and breathing become very slow and their muscles relax.
Stage 4. The deepest stage of sleep, known as true delta. Growth and repair processes occur during this stage.
REM sleep occurs regularly, about once every 90 to 120 minutes.
Brain waves in REM sleep are faster than in non-REM sleep.
REM sleep is associated with dreaming and with stimulation of the parts of the brain used for learning, while body repair and growth tends to happen during non-REM sleep.
The body clock
Sleep is regulated by an internal clock, that follows the day-night cycles (circadian rhythm).
When the sun sets, your brain starts to release sleepy chemicals, until you feel ready to go to bed.
In the morning, exposure to daylight prompts your brain to release awake chemicals.
Common sleep disorders
Insomnia: Difficulty falling asleep or staying asleep. Insomnia can be caused by factors such as stress, anxiety, depression, parenthood, financial strain, work and relationship problems, bereavement, pain, substance abuse, caffeine, nicotine and alcohol-use.
Jet lag: A different time zone can disrupt the body's internal clock, which takes a few days to reset. Working night shift can mimic the symptoms of jet lag.
Narcolepsy: Extreme tiredness and intermittent sleepiness during the day; can include involuntary napping.
Periodic limb movement disorder: muscle spasms of the legs that often wake up the sleeper. This is more common in the middle aged people and the elderly.
Restless legs: Cramps or lower leg irritations, which makes the person need to move their legs or get up and walk around.
Snoring: Breathing through the mouth while asleep; making hoarse or harsh sounds. Snoring is more common in males.
Sleep apnoea: The upper airway is blocked, causing airflow and breathing to stop for a time during sleep.
Sleep starts: Feeling of muscle jerks or a sensation of falling that happens when a person is just going off to sleep.
Sleepwalking: Affects children more than adults.
REM sleep behaviour disorder: The sleeper tends to act out what's happening in their dreams, which could mean punching or kicking.
Treatments for Insominia
- Treating underlying medical or psychological conditions.
- Stress management and relaxation techniques.
- Cognitive behaviour therapy - developing good sleeping habits.
- Light therapy.
- Sleep journals.
- Sleeping tablets (short term use).
- Lifestyle changes - diet and exercise.
Sleep tips
- Have a bath or shower before bedtime.
- Drink a cup of milk or camomile tea.
- Wear bed socks to keep your feet warm.
- Don't watch TV/use laptops in bed.
- Make sure bedroom is cool and dark.
- Avoid strenuous exercise or eating just before going to bed.
- Don't smoke or drink caffeine drinks before bedtime.
- Cover up illuminated alarm clocks.
- Leave mobile phones in another room.
