Obstructive sleep apnea (OSA)

What do the words mean?

Obstructive means that something restricts passage. Sleep describes when the breathing problem occurs. Apnea is a particular type of breathing event. OSA can include both apneas and hypopneas, even though hypopnea is not part of the name.

The abbreviation OSA appears in referrals, medical records, and sleep-study reports. The word obstructive matters because it distinguishes this condition from central sleep apnea, in which the control of breathing is the main issue.

Sources: NHLBI: What Is Sleep Apnea? · AASM: Rules for Scoring Respiratory Events in Sleep (2012 update)

What happens in the upper airway?

The upper airway is the passage air travels through before reaching the lungs. In OSA, tissues around the throat can narrow or collapse during sleep. Airflow becomes restricted even while the chest and abdomen show breathing effort.

This is why OSA is not simply a measure of how loudly someone snores. Sound, airflow, breathing effort, oxygen levels, and sleep provide different information that may need to be considered together.

Sources: NHLBI: What Is Sleep Apnea?

Symptoms and diagnosis are different

Snoring, witnessed breathing pauses, and gasping can raise concern about sleep apnea. Some people experience daytime sleepiness or difficulty functioning as usual. Symptoms vary, and no single description establishes the diagnosis.

For example, two people may both report disruptive snoring but have different test findings. They may need different advice and follow-up. A similar noise problem does not necessarily mean the same medical condition.

Sources: NHLBI: Symptoms

Understanding the diagnosis in a report

A report may include a respiratory event index and other information about breathing, oxygen, and sleep. Your clinician interprets these findings with your symptoms and history. Ask what supports the conclusion instead of treating one number as a complete health assessment.

Terms such as mild, moderate, and severe describe classifications. They do not, by themselves, explain someone’s daily experience or select a treatment. This entry primarily concerns adults; children require an age-appropriate evaluation.

Sources: AASM diagnostic testing guideline, 2017, original paper

Where to read next

The main sleep apnea guide explains the path from concerns and symptoms to testing, treatment, and follow-up. If your immediate question is what a test involves, start with the guide to sleep apnea evaluation.