Obesity is only one risk factor for sleep apnea syndrome. Individuals with a normal weight or who are thin can still experience this condition if other risk factors are present.

The most common type of sleep apnea is obstructive sleep apnea (OSA). This occurs when the upper airway narrows or completely closes intermittently during sleep, reducing or stopping airflow despite the body's continued efforts to breathe.

In overweight individuals, fat accumulation around the neck, tongue, and upper airway can constrict the breathing passage, making it more prone to collapse during sleep. However, for people with a normal weight or who are thin, doctors typically focus on the craniofacial structure and airway.

Individuals with a small or recessed lower jaw, a naturally narrow airway, a large tongue, enlarged tonsils, or certain pharyngeal anatomical features may be at risk for airway obstruction during sleep, even without significant body fat. These characteristics related to skull, facial, and respiratory tract shapes are often linked to family and genetic factors.

This mechanism is more pronounced during sleep. When awake, throat muscles help keep the airway open. During sleep, muscle tone decreases, and the tongue and soft tissues at the back of the throat tend to shift, narrowing the airway. If a person already has a small airway, this change can be enough to cause intermittent obstruction. The affected individual stops breathing for brief periods, blood oxygen levels decrease, and the brain triggers very short awakenings to restart breathing. This process can repeat many times in one night without the person's awareness.

Master, Doctor, Level II Specialist Nguyen Thi My Hanh examines a young man's throat. Illustration: Tam Anh General Hospital

Beyond airway structure, age, gender, family history, and certain endocrine conditions can also increase the risk. Consuming alcohol before sleep can cause the muscles in the mouth and throat to relax excessively, while smoking can lead to inflammation and swelling of the upper airway. Therefore, assessing risk for sleep apnea based solely on external appearance or weight is insufficient.

Key warning signs include loud, frequent snoring, especially when snoring is interspersed with silent pauses due to stopped breathing, followed by gasping for air or a choking sensation. During the day, affected individuals may experience excessive sleepiness despite sufficient sleep, fatigue, morning headaches, dry mouth upon waking, reduced concentration, or irritability. Not every person who snores has sleep apnea, but snoring accompanied by breathing pauses is a symptom that requires medical evaluation.

Repeated airway obstructions can lead to decreased blood oxygen levels, fragmented sleep, and strain on the cardiovascular system. Untreated sleep apnea is associated with an increased risk of hypertension, cardiac arrhythmias, myocardial infarction, heart failure, and stroke.

Therefore, thin or normal-weight individuals should not rule out the risk based solely on their weight. If you experience prolonged loud snoring, your family observes you stopping breathing during sleep, you frequently wake up choking, or you suffer from excessive daytime sleepiness, you should seek medical attention. Polysomnography or other appropriate sleep studies can determine the presence, type, and severity of sleep apnea, allowing for the development of a suitable treatment regimen.

Master, Doctor, Level II Specialist Nguyen Thi My Hanh

Department of General Internal Medicine

Tam Anh General Clinic District 7