Obstructive sleep apnoea is a breathing problem that only happens while you are asleep, which is exactly why it is so easy to miss. The airway relaxes, narrows and repeatedly closes; each closure starves you of air until your brain briefly wakes you enough to reopen it. You almost never remember these arousals. What you notice is the daytime: you slept eight hours and feel like you slept four. The most reliable signs are loud snoring, someone witnessing you stop breathing or gasp, and heavy sleepiness that rest does not fix.
Key takeaways
- Sleep apnoea is diagnosed by what happens to your breathing, not by how tired you feel. Tiredness is the consequence, not the test.
- The three highest-value signs are loud habitual snoring, witnessed pauses or gasping, and unrefreshing sleep despite adequate time in bed.
- Half the useful information sits with whoever sleeps next to you. Ask them.
- Screening questionnaires like STOP-BANG are good at catching people who need testing, but they cannot diagnose or exclude the condition on their own.
- Thin people get sleep apnoea too. Weight raises risk; it is not a requirement.
- If apnoea is likely, that changes the plan before any sleep medication is considered.
What is actually happening
During sleep, the muscles holding your upper airway open lose tone. In most people the airway narrows a little and nothing much happens. If your airway is naturally narrow, crowded or unusually collapsible, that narrowing goes further: airflow drops (a hypopnoea) or stops entirely (an apnoea).
Oxygen falls. Carbon dioxide rises. Your brain responds with a short burst of arousal, muscle tone returns, the airway snaps open, and you breathe again, often with a gasp or a snort. Then you fall back asleep and the cycle restarts. In moderate to severe cases this can repeat dozens of times an hour, all night, without a single memory of it in the morning.
Two things follow from that mechanism, and they explain nearly every symptom:
- Your sleep is shredded into fragments even though the clock says you were in bed for eight hours. Hence the exhaustion that rest does not repair.
- Your oxygen level swings up and down all night, and your cardiovascular system reacts to every one of those swings. Hence the blood pressure connection.
The signs you can notice yourself
- Waking unrefreshed, consistently. The single most common complaint. Time in bed is adequate; the benefit is not.
- Daytime sleepiness that ambushes you. Not just tired, but genuinely fighting sleep in meetings, in traffic, in front of the television. Falling asleep unintentionally during the day is a signal worth acting on.
- Waking with a dry mouth or sore throat, from a night of mouth breathing.
- Morning headache, typically dull, frontal, and easing over the first hour or two after waking.
- Waking to urinate more than once without another explanation. Disrupted sleep and the pressure changes of obstructed breathing both drive this.
- Waking with a jolt, a gasp or a choking sensation. Uncommon but highly specific. Take it seriously.
Notice what is not on that list: lying awake unable to fall asleep. That is insomnia, a different problem with different treatment. The two can coexist, and often do, but the sleepiness of apnoea and the wired wakefulness of insomnia are opposite experiences.
The signs someone else notices
This is where most sleep apnoea is actually found. If you share a bed or a room, ask directly:
- Do I snore loudly, most nights?
- Have you seen me stop breathing?
- Do I gasp, choke or snort myself awake?
- Do you leave the room, or wish you could, because of the noise?
Witnessed apnoeas are the highest-value piece of information in the entire history, and you cannot self-report them. If you sleep alone, a phone left recording audio overnight is a crude but genuinely useful substitute.
STOP-BANG: the screening tool clinicians use
STOP-BANG is the standard screening questionnaire, and it is used in South African practice. Score one point for each:
| Item | |
|---|---|
| S | Snoring loudly enough to be heard through a closed door |
| T | Tiredness or daytime sleepiness |
| O | Observed apnoea: someone has seen you stop breathing |
| P | Pressure: treated or untreated high blood pressure |
| B | BMI over 35 kg/m² |
| A | Age over 50 |
| N | Neck circumference over 40 cm (women) or 42.5 cm (men) |
| G | Gender: male |
A score of 3 or more puts you in the high-risk group and justifies testing. A score under 2 makes significant sleep apnoea considerably less likely.
The honest caveat, stated plainly in the South African literature: STOP-BANG is sensitive but not specific, particularly for mild disease. In plain terms, it is good at catching people who should be tested and poor at telling you what you have. A high score is a reason to test, not a diagnosis. A low score is reassurance, not an all-clear.
Who is at higher risk
Risk rises with excess weight, male sex, age, a large neck circumference, and high blood pressure. Alcohol in the evening makes any given night worse by relaxing the airway further. Sleeping on your back concentrates events, because gravity pulls the tongue and soft palate backwards.
Some anatomical factors have nothing to do with weight at all: a set-back lower jaw, a crowded oropharynx, large tonsils, nasal obstruction. This is why the assumption that a slim person cannot have sleep apnoea is wrong, and why it delays diagnosis in exactly the people who least expect it.
How it gets confirmed
Sleep apnoea is confirmed by measuring your breathing while you sleep, either with a full in-laboratory polysomnogram or a simpler home study. Severity is reported as the apnoea-hypopnoea index, the average number of breathing events per hour of sleep: 5 to 14 is mild, 15 to 29 moderate, and 30 or more severe.
What that testing involves in South Africa, and how to get access to it, is its own subject, covered in our guide to sleep studies in South Africa.
Why we screen for this before anything else
Slumbr is an insomnia clinic, and we screen every patient for sleep apnoea before considering any sedating treatment. That is deliberate and it is not a formality.
If your unrefreshing sleep is caused by an airway that closes two hundred times a night, a sleep medication does not fix the airway. It can make you less aware of a problem that is still happening, and the cardiovascular consequences of untreated apnoea accumulate regardless of how well you think you slept. Getting the diagnosis right first is the whole point. We cover this in detail in why sleeping tablets are the wrong answer for undiagnosed sleep apnoea.
Frequently asked questions
Can you have sleep apnoea without snoring? Yes, though it is less common. Snoring is the noise of a partly open airway vibrating; some people obstruct with relatively little sound, and snoring can also fade as obstruction becomes more complete. Absence of snoring lowers the probability but does not exclude the condition, particularly when witnessed pauses or heavy daytime sleepiness are present.
Can you have sleep apnoea if you are not overweight? Yes. Excess weight is the strongest modifiable risk factor, but airway anatomy matters independently: a set-back jaw, large tonsils, nasal obstruction or a naturally crowded airway can produce obstruction at any body size. Being slim is not a reason to dismiss witnessed apnoeas.
Is sleep apnoea the same as insomnia? No, and they often get confused because both produce exhausted people. Insomnia is difficulty falling or staying asleep, with the mind typically alert. Sleep apnoea is a breathing disorder that fragments sleep you are not aware of losing, producing sleepiness rather than wakefulness. They can occur together, which is why a proper assessment looks for both.
What happens if sleep apnoea goes untreated? The sleep fragmentation causes ongoing daytime sleepiness, with the road-safety risk that carries. The repeated oxygen swings and sympathetic surges are why untreated obstructive sleep apnoea is associated with high blood pressure and cardiovascular disease. This is a condition worth diagnosing properly rather than living around.
My partner says I stop breathing, but I feel fine. Does that still matter? Yes. Witnessed apnoeas are one of the strongest indicators there is, and feeling fine is not a reliable guide, partly because sleepiness that develops gradually over years gets normalised. It is worth testing.
Related reading
- Snoring vs sleep apnoea: how to tell ordinary snoring from the snoring that signals obstructed breathing.
Slumbr's free Sleep Pattern Assessment includes a sleep apnoea screen and will tell you if your answers suggest a formal apnoea work-up.
This article is educational and is not a diagnosis or a substitute for medical advice. Slumbr does not provide emergency care. If you are in crisis, seek urgent in-person help.
Not sure whether your problem is your breathing or your sleep pattern? Take the free Slumbr Sleep Pattern Assessment™, which screens for sleep apnoea alongside the insomnia phenotypes. Or book an online consultation with a specialist physician.