Hypersomnia means excessive sleepiness. There are many different causes including inadequate sleep, shiftwork, sleep disorders, medication, and medical and psychiatric illnesses (including depression). The major features of hypersomnia vary from one person to the next, depending on age, lifestyle and underlying causes. A major danger from hypersomnia is the increased risk of accidents.
Hypersomnia means excessive sleepiness. There are many different causes, the most common in our society being inadequate sleep. This may be due to shiftwork, family demands (such as a new baby), study or social life. Other causes include sleep disorders, medication, and medical and psychiatric illnesses.
Hypersomnia can be helped or cured with a few adjustments to lifestyle habits. Seek advice from your doctor or sleep disorder clinic if you still feel excessively sleepy.
Characteristics of hypersomnia
The characteristics of hypersomnia vary from one person to the next, depending on their age, lifestyle and any underlying causes. Under the International Classification of Sleep Disorders, daytime sleepiness is defined as ‘the inability to stay awake and alert during the major waking episodes of the day, resulting in unintended lapses into drowsiness or sleep’.
In extreme cases, a person with hypersomnia might sleep soundly at night for 12 hours or more, but still feel the need to nap during the day. Sleeping and napping may not help, and the mind may remain foggy with drowsiness. It is possible that a person with hypersomnia may have very disturbed sleep but not be aware of it.
Symptoms of hypersomnia
Depending on the cause, the symptoms of hypersomnia may include:
- Feeling unusually tired all the time
- The need for daytime naps
- Feeling drowsy, despite sleeping and napping – not refreshed on waking up
- Difficulty thinking and making decisions – the mind feels ‘foggy’
- Memory or concentration difficulties
- An increased risk of accidents, especially motor vehicle accidents.
Causes of hypersomnia
Excessive daytime sleepiness can be caused by a wide range of events and conditions, including:
- Insufficient or inadequate sleep – long working hours and overtime can be tolerated for months or years before the symptoms of sleepiness take effect. Teenagers who stay out until the early hours of the morning on weekends may be tired during the week.
- Environmental factors – broken sleep can be caused by a variety of things such as a snoring partner, a baby that wakes, noisy neighbours, heat and cold, or sleeping on an uncomfortable mattress.
- Shiftwork – it is very difficult to get good sleep while working shiftwork, especially night shift. As well as the problem of trying to sleep, there is also the effect of being out of synchronisation with the body’s internal clock (the circadian rhythm).
- Mental states – anxiety can keep a person awake at night, which makes them prone to sleepiness during the day. Depression saps energy.
- Medications – such as alcohol, caffeinated drinks, tranquillisers, sleeping pills and antihistamines can disrupt sleeping patterns.
- Medical conditions – like hypothyroidism (underactive thyroid gland), oesophageal reflux, nocturnal asthma and chronic painful conditions can disrupt sleep.
- Changes to time zone – such as jet lag can affect the internal biological clock, which regulates sleep. This clock responds to light.
- Sleep disorders – such as sleep apnoea, restless legs syndrome, sleep walking, narcolepsy, idiopathic hypersomnia and insomnia may all cause sleep disruption or fragmented sleep.
Some of the sleep disorders that may contribute to or cause excessive daytime sleepiness include:
- Sleep apnoea – the person’s breathing stops or is reduced regularly during sleep, sometimes every minute. The brain registers the breathing problem and sends a ‘wake-up’ call. The person rouses slightly, gasps and then goes back to sleep. Sleep is fragmented.
- Insomnia – this is very common, but does not necessarily cause hypersomnia. A person may have difficulty getting to sleep or staying asleep. Insomnia is a symptom, not a disease.
- Restless legs syndrome – sensations of cramps or irritation are felt under the skin in the legs, particularly the calves. The person feels compelled to move their legs or get out of bed and walk around.
- Sleep walking – this is a common abnormal behaviour during sleep. The person may walk around the house while still asleep. Sleep walking tends to affect children more than adults.
- Narcolepsy – this is a relatively rare sleep disorder characterised by sleepiness to the degree of involuntary napping, paralysis of the muscles (sleep paralysis), vivid, dream-like hallucinations just prior to falling asleep (hypnagogic hallucinations), and muscle weakness during periods of strong emotion (cataplexy).
- Idiopathic hypersomnia – this sleep disorder is characterised by excessive night-time sleeping and the need for naps during the day. Unlike narcolepsy, it doesn’t include cataplexy or sleep paralysis.
Diagnosis and treatment of hypersomnia
Identifying the causes of excessive sleepiness may involve investigations into lifestyle habits, medications, physical health and emotional state. Sleep disorders need to be diagnosed and treated at a sleep disorders clinic. The treatment depends on the disorder.
Hypersomnia can be helped in many cases with lifestyle adjustments to improve sleep quality, so called good sleep hygiene. Suggestions include:
- Avoid cigarettes, alcohol and caffeinated drinks near bedtime.
- Follow a relaxation routine to prevent night-time anxiety.
- Exercise regularly and maintain a normal weight for your height.
- Eat a well-balanced diet to prevent nutritional deficiencies.
- If possible, change your environment to reduce disturbances – for example, don’t watch television in the bedroom.
- Be comfortable; make sure you don’t overheat or feel too cold in bed.
- Have a regular sleeping routine so that your body ‘knows’ it is time to sleep.
- Only go to bed when you feel sleepy.
- If necessary, take brief ‘power’ naps during the day to help you stay alert and vigilant. Daytime napping is generally not recommended when improved sleep is possible, as it can reduce the drive to sleep at night. However, brief naps can be very valuable in occupational settings and on other occasions where concentration is required, such as preparation for driving or in regular breaks on a long trip.
Where to get help
- Your doctor
- Sleep disorder clinic
Things to remember
- Hypersomnia is excessive sleepiness. There are many causes of excessive sleepiness, including insufficient or inadequate sleep, sleep disorders, medications and medical or psychiatric illnesses.
- The characteristics of hypersomnia vary from one person to the next depending on age, lifestyle and underlying causes. A major danger from hypersomnia is the increased risk of accidents.
- Many people with hypersomnia can be helped or cured with a few adjustments to lifestyle habits.
- Sleep disorders need to be diagnosed and treated at a sleep disorders clinic.
You might also be interested in:
- Restless legs syndrome (RLS).
- Sleep - common disorders.
- Sleep - insomnia.
- Sleep - narcolepsy.
- Sleep apnoea.
Want to know more?
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This page has been produced in consultation with and approved by:
(Logo links to further information)
Newcastle Sleep Disorders Centre
Fact sheet currently being reviewed.
Last reviewed: September 2011
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