What is Sleep Apnoea?

Snoring and the disturbance it causes used to be regarded as a joke about which little could be done. However, we now know that snoring can indicate that there are problems with breathing during sleep and might have long term effects on health.

During sleep all the body’s muscles become less active and relax. In most parts of the body this does not matter and indeed helps one to relax and sleep comfortably. However, when the muscles that help hold open the throat behind the tongue relax, it can lead to partial collapse and narrowing in this area. Even in normal people this increases the resistance to the flow of air when breathing in, but this is usually of no importance.

When the narrowing that occurs during sleep is more than normal, then the airway behind the tongue collapses much more. To start with this causes snoring and then, if the collapse is complete, it causes what is called an apnoea. This means “without breath” – literally stopping breathing. Fortunately the body is able to sense this increased obstruction to breathing and the sufferer wakes briefly,  takes a few deep breaths, and rapidly returns to sleep.

This change from deep sleep to light sleep or partial waking can occur every minute or so and leads to a very broken  pattern of sleep. Because of this sleep apnoea sufferers are unrefreshed by sleep even though they may not remember these episodes of wakening or arousal.

WHAT CAUSES SLEEP APNOEA?

Sleep Apnoea is caused by anything that increases the normal narrowing of the throat during sleep (upper airway obstruction).

Anything that makes the throat narrower to start with (for example enlarged tonsils or a set back lower jaw) means that it is easy for the throat to close off a bit more and block the airway.

A partially blocked nose causes lower pressures in the throat whilst taking a breath in, which tends to suck the walls of the throat together. Probably the most important factor is being overweight with a large neck.

Extra fat in the neck squashes the throat from outside, particularly when the throat muscles become floppier with sleep.

WHO GETS SLEEP APNOEA?

The sort of person who most commonly suffers from heavy snoring and sleep apnoea is an overweight middle-aged man with a large neck, usually taking a size 17 inch collar or more. However, there are many people with sleep apnoea who are not particularly overweight, and in some we simply do not understand why they have sleep apnoea. In children the commonest cause is enlarged tonsils. Nowadays sleep apnoea is a common reason for recommending that a young child has their tonsils out.

Sleep apnoea and heavy snoring, severe enough to interfere with sleep quality, is probably much more common than is realised. At least three in every thousand men have severe sleep apnoea.

SYMPTOMS OF SLEEP APNOEA

Severe daytime sleepiness is the main sympton caused by the body having to wake up briefly throughout the night to clear the upper airway obstruction.

To start with sleepiness occurs only during potentially boring activities such as reading, watching television or driving on motorways. However when the sleepiness gets worse it begins to interfere with most activities, with sufferers even falling asleep whilst talking or eating. Poor work performance can lose the sufferer his or her job and of course sleepiness whilst driving can be fatal (sleep apnoea sufferers are about seven times more likely to have car accidents). Snoring will usually have been present for many years and have gone well beyond a joke within the family.

There are many other symptoms, as one might expect in someone who is seriously sleep deprived, (irritability for example) but the twin symptoms of snoring and daytime sleepiness are the best pointers to the diagnosis however any of the following may also occur:

  • Daytime fatigue & tiredness.
  • Snoring often punctuated by silences followed by a loud snort  (N.B. although as a general rule Sleep Apnoea sufferers snore this is not always the case.)
  • Sleeping partner is aware that there is regular cessation of breathing.
  • Increased need to visit the bathroom to pass urine during the night (Nocturia)
  • Waking up choking or being aware that the pulse is racing or heartbeat is rapid
  • Waking up fuzzy headed and feeling unrested.
  • Sore throats on waking.
  • Dry mouth on wakening
  • Reduced sex drive.
  • General irritability, difficulty concentrating and poor memory.
  • High blood pressure (caused usually by untreated Sleep Apnoea)
  • Usually overweight.

DIAGNOSIS OF SLEEP APNOEA

The presence of significant sleep apnoea may be strongly suspected from the symptoms. Often the individual’s partner has read an article about sleep apnoea and recognises that this must be what their partner has.

Once sleep apnoea is suspected then a sleep study is done to confirm the diagnosis. A hospital referral to a sleep specialist is necessary for this. A variety of measurements can be made during a sleep study without discomfort. Oxygen levels in the blood can be continuously measured from a clip on the finger and breathing monitored from belts around the chest and tummy. Sleep quality itself can be estimated from wires stuck to the scalp or from the number of body movements made during sleep.

Specialist sleep units investigating a wide range of sleep disorders may use video recordings with sound to observe sleep disturbances including night terrors and sleep walking.

TREATMENT

When sleep apnoea and snoring are not severe then simple approaches can help. Losing some weight, not drinking alcohol after 6.00 pm (alcohol relaxes the upper airway muscles even more), keeping the nose as clear as possible, and sleeping on one’s side or semi-propped up can all help. There are now simple dental devices, like sports-type gum shields, worn at night that can greatly reduce snoring that are easily obtained. More sophisticated versions can be obtained through a specialist dentist. When snoring is very objectionable, then an operation on the back of the throat may help – but this is a last resort and should only be done when a sleep study has shown snoring alone with very little, or no, sleep apnoea.

The only really effective treatment currently used for symptomatic sleep apnoea is continuous positive airway pressure ( CPAP). Because the inside of the throat narrows, it can be held open by slightly pressurised air. To deliver this air a mask is worn during sleep over the nose or nose and mouth and connected to a small, quiet pump beside the bed. Breathing is then able to return to normal during sleep with the air gently blowing through the nose, holding open the throat. The response is usually dramatic with greatly improved sleep and improvement of the day-time sleepiness. Although these devices are cumbersome to wear, and hardly improve one’s appearance, the benefits far outweigh the disadvantages in most cases.

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