Loud snoring, gasping at night and constant daytime tiredness can be signs of sleep apnoea, a common condition that often goes undiagnosed. A sleep study measures what really happens while you sleep.
Imagine your partner nudging you awake because you stopped breathing for a few seconds, then snored loudly again. You wake up exhausted, nod off in meetings and worry about falling asleep at the wheel.
Why a sleep study might be recommended
- Loud snoring with pauses in breathing or gasping, noticed by a partner
- Excessive daytime sleepiness, dozing off while reading, watching TV or driving
- Waking with headaches or a dry mouth
- High blood pressure that is hard to control
- Suspected narcolepsy, unusual movements or behaviours during sleep
- Checking how well treatment for sleep apnoea is working
Types of sleep study
- Home sleep apnoea test: you wear a small device at home for one or more nights, usually measuring breathing, oxygen levels and heart rate
- Overnight oximetry: a simple finger probe records oxygen levels and pulse
- Polysomnography: a detailed overnight study, usually in a sleep centre, recording brain waves, eye movements, muscle activity, breathing, oxygen, heart rhythm and leg movements
- Multiple sleep latency test: a daytime test measuring how quickly you fall asleep, used to investigate narcolepsy
Preparing for the test
- Follow your usual routine as much as possible
- Avoid naps on the day, unless told otherwise
- Avoid caffeine in the afternoon and evening, and avoid alcohol
- Wash your hair and avoid hair products, as they can affect sensors
- Bring comfortable night clothes and anything that helps you sleep, such as your own pillow
- Take your usual medicines unless told otherwise
What happens during a home test
You will be shown how to fit the device, often a small box worn on the chest with a belt, a nasal tube to measure airflow, and a finger probe for oxygen. You go to bed as normal and return the device the next day.,Home tests are convenient and widely used for suspected obstructive sleep apnoea. If results are unclear, a full overnight study may be needed.
What happens during an overnight study
You arrive in the evening and a technician attaches small sensors to your scalp, face, chest and legs with tape or paste, plus a nasal tube and finger probe. It looks like a lot of wires, but most people still manage to sleep.,The room is usually like a hotel bedroom, and a technician monitors you from another room. You can get up to use the toilet. In the morning, the sensors are removed and you can usually go home and continue your day.
Understanding the AHI
The apnoea-hypopnoea index (AHI) is the main measure of sleep apnoea. It counts how many times per hour your breathing stops (apnoea) or becomes very shallow (hypopnoea) during sleep.,In adults, an AHI below 5 is usually considered normal, 5 to 14 mild, 15 to 29 moderate and 30 or more severe. Healthcare providers also look at oxygen levels, symptoms and other health conditions when deciding on treatment.
Why sleep apnoea matters
Untreated obstructive sleep apnoea is linked to high blood pressure, heart disease, stroke, type 2 diabetes, low mood and road accidents caused by sleepiness. Treatment can greatly improve energy, concentration and quality of life, for both you and your partner.
Treatment options
- CPAP (continuous positive airway pressure), a mask worn at night that keeps the airway open; the most effective treatment for moderate to severe sleep apnoea
- Mandibular advancement devices, which hold the lower jaw forward, for mild to moderate cases
- Weight loss, which can reduce or even resolve sleep apnoea in some people
- Avoiding alcohol and sedatives before bed
- Sleeping on your side
- Surgery in selected cases
Getting used to CPAP
Many people find CPAP strange at first. Common problems include a mask that leaks or feels uncomfortable, a dry mouth or nose, and feeling claustrophobic. These usually improve with adjustments: trying a different mask style or size, using a humidifier, or wearing the mask while awake to get used to it.
Sticking with CPAP pays off. Many people notice they wake feeling refreshed for the first time in years, and partners often sleep better too. Your sleep team can help with problems, so do not give up without asking for support.
Children and sleep apnoea
Children can also have sleep apnoea, often due to enlarged tonsils or adenoids. Signs include loud snoring, pauses in breathing, restless sleep, bedwetting, daytime tiredness, behavioural problems and difficulty concentrating. Removing the tonsils and adenoids often helps. A child with these symptoms should see a healthcare provider.
Questions to ask about your results
- What was my AHI, and how severe is my sleep apnoea?
- How low did my oxygen levels fall?
- Which treatment do you recommend, and why?
- Do I need to tell my driving licence authority?
- When will I be followed up?
Frequently asked questions
What if I cannot sleep during the test?
Most people sleep enough for useful results. If not, the test may be repeated.
Do I have to stop driving?
If you are excessively sleepy, you should not drive. Rules about telling licensing authorities vary by country; ask your healthcare provider.
Is CPAP for life?
Often it is long term, but some people improve with weight loss or other changes.
But I only snore. Do I really need a test?
Many people snore without sleep apnoea. But if you have pauses in breathing, gasping or daytime sleepiness, a test is worth having.
Your next step: Ask your partner to note whether you stop breathing or gasp at night, and take this information to your healthcare provider.
Related: Sleep apnoea symptoms · Insomnia and sleep hygiene
Sources: American Academy of Sleep Medicine, British Lung Foundation (Asthma + Lung UK), National Institute for Health and Care Excellence (NG202), US National Heart, Lung, and Blood Institute.
Leave a Reply