Sleep apnea

Sleep apnea is a sleep disorder in which breathing is repeatedly interrupted or stops entirely during sleep. These pauses in breathing can last from a few seconds to several minutes, and are often long enough to:

• Disrupt sleep

• Lower oxygen levels in the blood

• Increase carbon dioxide (CO₂) levels in the blood

Breathing Pauses and Types of Sleep Apnea

Breathing pauses may occur more than 30 times per hour and have a significant negative effect on sleep quality. Therefore, sleep apnea is one of the most common causes of pronounced daytime sleepiness¹.

There are three main types of sleep apnea: central, obstructive, and mixed.

Obstructive sleep apnea (OSA) is by far the most common, and it is this type that is further described here.

• Obstructive sleep apnea (OSA): Caused by repeated partial or complete blockages of the upper airways during sleep. This leads to reduced or stopped breathing, a drop in blood oxygen, and a rise in CO₂ levels.

• Central sleep apnea: Occurs when the brain does not register changes in CO₂ levels and therefore does not send signals to the respiratory muscles to increase breathing depth.

• Mixed sleep apnea: A combination of obstructive and central breathing pauses during the night¹.

Causes (Etiology)

OSA occurs when there is not enough space in the upper airways to maintain normal airflow during sleep.

When muscle tone in the throat and pharyngeal muscles decreases during sleep, this may cause the airways to partially or completely collapse – thereby blocking airflow.

• In children: the most common cause is enlarged tonsils or adenoids.

• In adults: it is most associated with obesity, male sex, and increasing age².

Factors that increase the risk of airway obstruction:

• Obesity

• Large neck circumference

• Enlarged tonsils or tongue

• Narrow pharynx due to skeletal structure in the head/neck

• Use of sleeping pills or sedatives

• Alcohol use

• Smoking

• Nasal congestion

Medical conditions associated with OSA:

• Stroke

• Hypothyroidism

• Metabolic syndrome

• Acromegaly

• Neurological diseases such as myasthenia gravis²

Epidemiology

In the United States, it has been reported that approximately 4% of men and 2% of women meet the criteria for OSA. More recent studies show that prevalence may be as high as 14% in men and 5% in women.

Prevalence is higher among Hispanics, African Americans, and Asians². It increases with age, and after the age of 50, men and women are affected at roughly the same rate. Genetic factors and craniofacial structural features also increase risk. Having a first-degree relative with OSA doubles the risk²,⁴.

OSA is common in occupational groups with prolonged sedentary activity, such as truck drivers⁵.

Clinical Presentation

Adults with OSA:

• Overweight or obese middle-aged man or postmenopausal woman

• Pronounced daytime sleepiness and loud snoring at night

• Frequent awakenings with choking or gasping for breath

• Sleep disturbances, night sweats, acid reflux during the night, frequent urination without increased fluid intake

• Large neck circumference (over 43 cm in men), narrow pharynx, large tongue

• May have retrognathia (recessed jaw)

• Patients with treatment-resistant atrial fibrillation, hypertension, or history of stroke should always be screened for OSA²

Children with OSA:

• Loud snoring

• May present as hyperactive rather than sleepy

• Learning difficulties and school problems, often misdiagnosed as ADHD

• Night sweats, reflux, restless sleep, frequent leg movements, and bedwetting

• Clinical findings: adenoidal face (long, open mouth, narrow maxilla), enlarged tonsils, nasal speech, high palate

• Children with Down syndrome or other hypotonia should always be assessed for OSA²

Treatment

In adults, CPAP (continuous positive airway pressure) is the gold standard. This delivers continuous positive airway pressure during sleep and can almost eliminate all symptoms if used consistently.

• In cases of intolerance or lack of electricity, customized oral appliances that hold the lower jaw forward can be used.

• Severe OSA may be treated with BiPAP (bilevel positive airway pressure), which provides different pressures for inhalation and exhalation, particularly in those requiring high pressures (>15–20 cm H₂O).

• All patients should be evaluated and treated for any nasal obstruction, either with nasal sprays or surgery.

• Positional therapy (sleeping on the side) may help in position-dependent OSA.

• Weight reduction is recommended and often improves symptoms but rarely cures the condition alone.

In children, removal of tonsils and/or adenoids (tonsillectomy/adenoidectomy) is first-line, but severity, symptoms, and age are always considered. In mild cases, medical treatment (montelukast, nasal spray) may be attempted.

Surgical alternatives for adults are only considered in severe, treatment-resistant OSA.

Diagnostics and Evaluation

Nocturnal polysomnography (PSG): 

The gold standard for diagnosis. During sleep, EEG (brain activity), pulse oximetry (oxygen saturation), airflow through nose/mouth, respiratory movements, ECG, and muscle activity are recorded.

• Apnea is defined as cessation of breathing for at least 10 seconds.

• Hypopnea is ≥30% reduction in airflow lasting at least 10 seconds, accompanied by ≥3–4% O₂ desaturation or arousal.

Home sleep tests: 

Increasingly common due to simplicity and lower cost. Used in adults with strong suspicion of OSA and no major comorbidities. Includes measurements of oxygen, pulse, airflow, respiratory movements, and body position.

Other assessments:

• Medical history: risk factors, comorbidities, snoring, sleep patterns

• Indexes: Apnea–Hypopnea Index (AHI), Respiratory Disturbance Index (RDI)

• Clinical exam: nose, pharynx, palate, tongue, neck, airways (requires experience for accurate assessment)

• Scoring tools: Epworth Sleepiness Scale (ESS), Berlin Questionnaire

• Oximetry: overnight O₂ saturation monitoring

• Additional blood tests and targeted investigations if needed

Consequences and Comorbidities

OSA leads to repeated periods of low oxygen, elevated CO₂, altered intrathoracic pressure, sympathetic nervous system activation, and fragmented sleep.

This results in:

• Metabolic disturbances

• Vascular damage (endothelial injury), systemic inflammation, oxidative stress, and increased risk of thrombosis

• Independent links to metabolic syndrome

• Higher risk of hypertension, cardiovascular disease, heart failure, arrhythmias, stroke, and pulmonary disease¹⁰

  
  

Physiotherapy and Physical Management in OSA

Although research provides limited evidence for specific physiotherapy interventions in OSA, physiotherapists play an important role in recognizing, informing, and referring patients with signs and symptoms. Many individuals with OSA remain undiagnosed, representing a major potential for early detection in primary care.

Undiagnosed OSA increases the risk of hypertension, cardiovascular disease, traffic accidents, and significantly reduced quality of life¹¹.

Physiotherapists can support patients by providing information on:

• Common signs and symptoms of sleep apnea

• Risk factors for developing the condition

• Associated comorbidities

• How diagnosis and evaluation are carried out

• The risks of leaving the condition untreated

Aerobic Physical Activity

Studies show that regular physical activity can reduce the severity of OSA, even without major changes in body weight. The most common interventions have been aerobic exercise for at least 30 minutes, 3–5 days per week. Exercise has documented positive effects on fitness, daytime sleepiness, and sleep efficiency, highlighting the importance of training as part of treatment¹².

Example of exercise programs from studies:

• 150 minutes per week of aerobic activity (treadmill, elliptical, or seated cycle ergometer), spread over four days, for twelve weeks

• Two of these weekly sessions combined with strength training (2 sets of 10–12 repetitions of eight different exercises)

Tongue Exercises

Physiotherapy interventions with muscle training of the tongue and pharynx may have a role in OSA, especially in mild forms. These exercises help counteract muscular hypotonia (low tone) that develops over time¹³.

Examples of tongue exercises:

• Tongue brushing: Use a toothbrush to brush the upper and side surfaces of the tongue while it rests against the floor of the mouth. Repeat each section 5 times, three times daily. This strengthens tongue muscles and improves oral hygiene.

• Tongue push: Look straight ahead, place the tongue tip behind the upper incisors, and push backward. Repeat 10 times. Strengthens tongue and pharyngeal muscles.

• Tongue strength: Press the tongue firmly against the palate for 4 seconds, repeat 5 times. Then press the posterior tongue down toward the floor of the mouth with the tip behind the lower incisors, hold for 4 seconds, repeat 5 times. Both strengthen the tongue and soft palate.

• Tongue press: Press the tongue against the hard palate, hold for 5 seconds, then move backward toward the posterior mouth. The anterior third of the tongue should remain against the palate. Keep the mouth open without biting, repeat 10 times, four times daily. This strengthens the genioglossus and hyoid muscles, helping stabilize the hyoid bone.

Breathing Training

Diaphragmatic breathing (abdominal breathing): 

Practicing slow, deep inhalations through the nose and exhalations through the mouth, with one hand on the abdomen to feel it rise during inspiration, can positively affect OSA. Systematic reviews from 2021 show that breathing training can improve the apnea–hypopnea index (AHI), reduce fatigue, and lessen daytime sleepiness¹⁴.

Methods of breathing training include:

• Inspiratory muscle training (IMT): Use of resistance devices (e.g., POWERbreathe) to strengthen inspiratory muscles¹⁷.

• Diaphragmatic breathing: Focusing on abdominal breathing rather than shallow chest breathing to strengthen respiratory muscles.

• Activities such as singing or playing wind instruments: These may positively impact breath control and muscle strength.

Regular breathing training can also reduce daytime sleepiness and improve sleep quality¹⁵,¹⁶.

Differential Diagnoses

Conditions that can present with similar symptoms and must be excluded during OSA evaluation:

• Asthma

• Central sleep apnea

• COPD (chronic obstructive pulmonary disease)

• Depression

• Gastroesophageal reflux disease (GERD)

• Hypothyroidism

• Narcolepsy

• Periodic limb movement disorder²

Sources

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14. Cavalcante-Leão BL, de Araujo CM, Ravazzi GC, et al. Effects of respiratory training on obstructive sleep apnea: Systematic review and meta-analysis. Sleep Breath. 2021.

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17. Vranish JR, Bailey EF. Inspiratory muscle training improves sleep and cardiovascular function in OSA. Sleep. 2016;39(6):1179–1185.

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