"I slept 7 hours, why am I so tired?" Chronic sleep deprivation is one cause, but there's another that's easy to miss — sleep apnea. About 300,000–500,000 Koreans have been diagnosed, but the real number is estimated at 5× that. It's a state in which your deep sleep is stolen every night without your knowledge.
What sleep apnea is
Obstructive sleep apnea (OSA) is when the airway narrows or closes during sleep, halting breathing for 10+ seconds at least 5 times an hour.
Severity grades:
- Mild: 5–14 events per hour
- Moderate: 15–29 per hour
- Severe: 30+ per hour
In severe cases, breathing stops 30 times an hour — 240 times across an 8-hour night. Each time, oxygen drops, the brain detects "danger," and briefly wakes you to restart breathing. You don't know you woke, but deep sleep barely happens.
Main signs — self check
Two or more of these mean you should test for apnea.
- Loud, harsh snoring: audible from another room.
- Family says "you stop breathing": the most decisive sign.
- Dry mouth and headache in the morning: from breathing through your mouth all night.
- Extreme daytime sleepiness: dozing off in meetings, while driving.
- Tired even after enough sleep: 8 hours feels like 4.
- Frequent bathroom trips at night: hormonal change from apnea.
- Morning erectile dysfunction: sign of overnight oxygen lack.
- Hard-to-control hypertension: apnea drives blood pressure up.
Risk factors
| Risk factor | Why it matters |
|---|---|
| Obesity (BMI 25+) | Neck fat compresses the airway |
| Male | 2–3× the rate of females |
| Age 50+ | Throat muscles weaken with age |
| Large neck (male 43 cm+, female 38 cm+) | Anatomical airway narrowing |
| Smoking | Airway swelling |
| Alcohol | Throat muscles relax, worsens apnea |
| Family history | Inherited anatomy |
Why sleep apnea is dangerous
Sleep apnea isn't just "loud snoring." Untreated long-term, it produces serious downstream consequences:
- Hypertension: blood pressure spikes with each event; 50%+ of patients have high BP.
- Cardiovascular disease: heart attack, arrhythmia, stroke risk 2–4×.
- Type 2 diabetes: insulin resistance worsens, risk 2–3×.
- Dementia: nocturnal oxygen lack causes neural damage — Alzheimer's risk up.
- Traffic accidents: drowsy-driving risk 2–7×.
- Depression and anxiety: same mechanism as chronic sleep deprivation.
Diagnosis — polysomnography
Definitive diagnosis requires polysomnography. You sleep one night at a sleep clinic with simultaneous EEG, breathing, oxygen, and heart-rate monitoring. Cost in Korea, with insurance: about 200,000–500,000 KRW.
Home sleep tests (HST) are now available for ~100,000–200,000 KRW. Slightly less accurate, but they catch clear apnea cases.
Treatment — CPAP is the standard
CPAP (Continuous Positive Airway Pressure) is a device that delivers steady-pressure air through a mask covering nose or mouth, holding the airway open. Its effect is overwhelming.
CPAP benefits:
- Daytime sleepiness clearly improves within a week.
- Blood pressure drops on average 10 mmHg within a month.
- Insulin sensitivity recovers within 3 months.
- Long term, cardiovascular mortality risk drops by 50%.
CPAP challenges:
- Adjustment period of 2–4 weeks (mask discomfort, air pressure).
- Inconvenient to travel with.
- Mask requires regular cleaning.
Many quit during the adjustment period, but those who stick with it for a month adapt; after 3 months they often "can't sleep without it."
Alternative treatments
For mild cases, or if CPAP can't be tolerated:
- Weight loss: 10% loss can drop apnea events by 30%.
- Side sleeping: fewer events than back sleeping. Anti-back-sleep pillows or a tennis ball in the shirt back.
- Cut alcohol: nothing within 3 hours of bed.
- Mandibular advancement device (MAD): pushes the lower jaw slightly forward to keep the airway open — effective for mild cases.
- Surgery: when there's an anatomical issue (enlarged tonsils, etc.) — a last resort.
One thing to do today
If you read this and recognize two or more warning signs in yourself, ask one simple question of family or your sleep partner: "Have you ever heard me stop breathing while snoring?" If the answer is "yes," book a test at an ENT clinic or sleep center. One test could change the next 30 years of your health.
