What is Sleep Apnoea?

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Sleep apnoea is a disorder in which breathing is interrupted repeatedly and is characterized by the presence of snoring and excessive daytime sleepiness.

Sleep Apnoea explained in first person

Professionals and patients explain how you live with the disease
Anyone who snores and whose partner has observed episodes of apnoea or who have daytime drowsiness should visit their primary care doctor and be aware that treating this condition will improve their ability to sleep well and, therefore, their quality of life.
The CPAP changed my life, because now I wake up and I feel happy and content. I'm not tired and I can do things. Above all, I’m not always falling asleep.

Sleep apnoea/hypopnoea syndrome (SAHS) is characterised by excessive daytime sleepiness, snoring and varying lengths of time with no breathing movements (apnoea).

People affected by sleep disorders may also develop neurocognitive, cardiorespiratory, inflammatory and metabolic disorders as a result of repeated episodes of total (apnoea) or partial obstruction (hypopnoea) of the pharynx. 

These episodes are accompanied by a reduction in blood oxygen levels and conclude with a brief awakening (arousal) which leads to unrefreshing sleep. 

Types of Sleep Apnoea

There are three different types of apnoea and hypopnoea:

Apneas obstructivas. Son las más frecuentes. Se caracterizan por el cese o la disminución del flujo aéreo en la boca y/o la nariz, a pesar de los esfuerzos de la musculatura ventilatoria que lucha contra una obstrucción situada en la región faríngea.

Central apnoea. The cessation or decrease in nasal-buccal airflow is accompanied by a pause or reduction in respiratory muscle activity due to a decline in the activity of the brain’s respiratory centre.

Mixed apnoea. The apnoea or hypopnoea is initially central and subsequently obstructive.

When it comes to SAHS, the condition predominantly involves hypopnoea and obstructive apnoea. Central apnoea is less common and may appear in a physiological form when awakening from sleep in people with no syndrome, but it may be pathological in patients with central nervous system (CNS) disorders or heart diseases that affect their control over their breathing.                                        

Sleep Apnoea cycle

The sequence of events that occur throughout the night in patients with SAHS gives rise to a series of pathophysiological changes which are responsible for the main symptoms associated with the illness.

The same cycle always repeats itself: sleep, apnoea, changes in blood oxygen and carbon dioxide concentration (blood gas analysis alterations), transient arousal and end of apnoea.

During apnoea, and as a consequence of the obstructed upper airway (UAW), an increasingly negative pleural pressure develops; in other words, an intense inspiratory effort is required to overcome the obstruction, which increases the cardiac afterload in both ventricles.

Repeated blood gas changes cause systemic and pulmonary vasoconstriction and in turn systemic arterial and pulmonary hypertension, which may induce other cardiovascular diseases such as coronary heart disease or cerebral stroke.

Heart arrhythmias are common, especially episodes of complete arrhythmia due to atrial fibrillation. In severely obese patients, nocturnal blood gas changes have a decisive influence over chronic daytime hypoventilation.

The latest findings indicate that hypoxic (lack of oxygen)–reoxygenation phenomena secondary to apnoea–hypopnoea phenomena and their termination are responsible for the appearance of oxidative stress (cell ageing and damage), free radicals, the release of inflammatory substances and cell death phenomena (apoptosis).

Repeated transient arousals, on the other hand, are responsible for sleep fragmentation, which determines most of the neuropsychiatric symptoms such as daytime sleepiness and cognitive disorders.

How many people are affected by Sleep Apnoea?

Its prevalence among the adult population is around 2–5% and this increases with age. It is 2–3 times more common in men than women, although the number of women affected rises significantly after menopause. 

Around 2 million people in Spain have SAHS, yet less than 10% of those affected are diagnosed and treated correctly. 

Substantiated information by:

Cristina Embid
Josep M. Montserrat Canal
M Concepción Ruiz Sánchez

Published: 16 January 2020
Updated: 16 January 2020

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