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Discover how sleep apnoea may affect heart health, its connection with high blood pressure and heart disease, common symptoms and available treatment options.
When breathing repeatedly stops or becomes shallow during sleep, oxygen levels can fall. The body responds by briefly waking up or increasing its activity to restore normal breathing. When this happens repeatedly throughout the night, it can affect blood pressure, heart rate and the body’s normal recovery process.
Research has identified a connection between sleep apnoea and several cardiovascular conditions, including high blood pressure, heart rhythm problems and heart failure. However, the relationship is complex, and having sleep apnoea does not automatically mean someone will develop heart disease.
In this guide, we explain how sleep apnoea affects the heart, the possible cardiovascular risks, common warning signs and available treatment options. Understanding the condition can help people recognise when they should seek medical advice and why managing sleep apnoea is important for their overall health.
What Is Sleep Apnoea?
Sleep apnoea is a sleep-related breathing disorder in which breathing repeatedly stops or becomes unusually shallow during sleep. These interruptions can last several seconds and may happen many times throughout the night.
The most common form is obstructive sleep apnoea (OSA). It occurs when the muscles and soft tissues at the back of the throat relax during sleep, narrowing or temporarily blocking the upper airway. As a result, air cannot move normally into the lungs.
When breathing is interrupted, oxygen levels may decrease. The brain responds by briefly bringing the person out of deeper sleep so that normal breathing can restart. These brief awakenings may happen without the person remembering them in the morning.
There are three main types of sleep apnoea:
This is the most common type. It occurs when the upper airway becomes partially or completely blocked during sleep, usually because the surrounding muscles and tissues relax.
Central sleep apnoea occurs when the brain temporarily fails to send the appropriate signals to the muscles responsible for breathing. Unlike obstructive sleep apnoea, the problem is not caused by a physical blockage in the airway.
Also called treatment-emergent central sleep apnoea, this describes a situation in which central breathing interruptions appear or persist in someone receiving treatment for obstructive sleep apnoea.
Although these conditions affect breathing in different ways, repeated interruptions to normal sleep can affect daytime alertness, energy levels and general health.
What Are the Symptoms of Sleep Apnoea?
Sleep apnoea can be difficult to recognise because most breathing interruptions happen while a person is asleep. Some people only become aware of the problem after a partner or family member notices their breathing patterns.
Common symptoms include:
- Loud and frequent snoring.
- Breathing that repeatedly stops and starts during sleep.
- Gasping, choking or snorting sounds during the night.
- Waking up frequently without an obvious reason.
- Feeling tired even after spending enough time in bed.
- Morning headaches.
- Difficulty concentrating during the day.
- Irritability or changes in mood.
- Waking with a dry mouth or sore throat.
Not everyone experiences all these symptoms. Some people may have noticeable breathing interruptions without feeling particularly sleepy during the day, while others mainly experience fatigue and poor concentration.
It is also important to understand that snoring alone does not confirm sleep apnoea. However, loud snoring combined with witnessed breathing pauses, gasping or persistent daytime tiredness should not be ignored.
If you recognise these signs, speak to your GP about whether a sleep assessment is appropriate. A sleep study can help determine whether breathing interruptions are occurring and how frequently they happen.
How Does Sleep Apnoea Affect the Heart?
The relationship between sleep apnoea and heart disease is linked partly to what happens inside the body when breathing repeatedly stops during sleep.
Under normal circumstances, breathing supplies oxygen to the body and helps maintain stable blood pressure and heart activity. With obstructive sleep apnoea, repeated airway blockages interrupt this process.
Each breathing interruption can trigger several changes.
When airflow is restricted, the amount of oxygen reaching the lungs and entering the bloodstream can decrease. The heart and other organs need a regular oxygen supply to function properly.
Repeated oxygen fluctuations throughout the night place the body under physiological stress.
When the brain detects a breathing interruption or falling oxygen levels, it activates the body’s alerting response. This can increase heart rate and release stress hormones such as adrenaline.
The heart may have to work harder during these episodes as the body attempts to restore normal breathing.
Breathing interruptions can cause temporary increases in blood pressure. Repeated episodes throughout the night may contribute to difficulties with long-term blood pressure control in some people.
Even when someone does not fully wake up, repeated interruptions can prevent normal sleep patterns from developing. Poor sleep quality can affect the body’s ability to regulate several important processes, including blood pressure and stress responses.
Over time, these repeated changes may contribute to cardiovascular strain, particularly when sleep apnoea is untreated and other risk factors are present.
What Heart Problems Are Associated With Sleep Apnoea?
Research has identified associations between obstructive sleep apnoea and several cardiovascular conditions. However, these associations do not mean that sleep apnoea directly causes every heart condition. Age, body weight, existing medical conditions and lifestyle factors can also influence cardiovascular risk.
The following are some of the main heart-related concerns.
High blood pressure is one of the most recognised cardiovascular conditions associated with obstructive sleep apnoea.
During an apnoea episode, the body responds to reduced airflow and oxygen levels by activating its stress response. This can cause temporary increases in heart rate and blood pressure.
When these episodes happen repeatedly, they may contribute to persistently elevated blood pressure.
Some people continue to experience high blood pressure despite taking medication. Sleep apnoea can be one of several conditions worth investigating in people with difficult-to-control hypertension.
Managing sleep apnoea may help improve blood pressure in some patients, although it does not replace prescribed blood pressure medication or regular medical monitoring.
Coronary artery disease develops when the arteries supplying blood to the heart become narrowed, usually because of a build-up of fatty deposits.
This can reduce the amount of oxygen-rich blood reaching the heart muscle.
Sleep apnoea has been associated with coronary artery disease in several studies. Repeated oxygen fluctuations, changes in blood pressure and increased activity of the body’s stress response may contribute to cardiovascular stress.
However, coronary artery disease has multiple risk factors, including smoking, diabetes, high cholesterol, high blood pressure and family history.
Sleep apnoea should therefore be considered as part of a person’s wider health assessment rather than treated as the only possible explanation.
The heart normally follows a regular electrical rhythm that controls how quickly and consistently it beats.
Sleep apnoea can affect this process. Repeated changes in oxygen levels, pressure inside the chest and activity of the nervous system may influence the heart’s electrical stability.
Some studies have found an association between obstructive sleep apnoea and atrial fibrillation, a common type of irregular heart rhythm.
Atrial fibrillation can cause symptoms such as:
- An irregular or unusually fast heartbeat.
- Heart palpitations.
- Shortness of breath.
- Dizziness.
- Unusual tiredness.
Some people with atrial fibrillation do not experience noticeable symptoms.
If you experience an irregular heartbeat or repeated palpitations, seek medical advice. A healthcare professional can investigate the cause and determine whether sleep apnoea may be contributing.
Heart failure occurs when the heart cannot pump blood around the body as effectively as it should. It does not mean that the heart has completely stopped working.
There is an established association between sleep-disordered breathing and heart failure. People with heart failure may also experience sleep apnoea, although the type and underlying mechanisms can vary.
Obstructive sleep apnoea may place additional demands on the cardiovascular system through repeated oxygen changes, increased blood pressure and pressure fluctuations inside the chest.
Common symptoms of heart failure include:
- Shortness of breath, particularly during physical activity.
- Swelling in the ankles, legs or feet.
- Persistent tiredness.
- Difficulty breathing when lying flat.
- Waking up breathless during the night.
These symptoms can have several possible causes. Anyone experiencing them should receive an appropriate medical assessment rather than assuming they are related to sleep apnoea.
A stroke occurs when the blood supply to part of the brain is interrupted or when bleeding occurs in the brain.
Obstructive sleep apnoea has been associated with an increased risk of stroke in observational research. High blood pressure, changes in blood vessel function and other cardiovascular risk factors may help explain this relationship.
People who have both sleep apnoea and existing cardiovascular conditions may need closer medical attention.
Why Does Untreated Sleep Apnoea Increase Cardiovascular Concerns?
The main concern with untreated sleep apnoea is that the body experiences repeated breathing interruptions over an extended period.
A single episode may last only a few seconds, but someone with moderate or severe obstructive sleep apnoea can experience many episodes during one night.
The body repeatedly responds by increasing alertness, changing heart rate and adjusting blood pressure. These responses are useful for restoring breathing in the short term, but repeated activation can create ongoing physiological stress.
There are also other factors to consider.
Repeated awakenings can affect the body’s normal sleep cycle and contribute to daytime fatigue.
Repeated changes in oxygen levels may contribute to biological processes associated with inflammation and damage to blood vessels.
People with diabetes, obesity or high blood pressure may already have an increased cardiovascular risk. Sleep apnoea can add another concern to their overall health picture.
Persistent tiredness may make it harder for some people to remain physically active and maintain healthy daily routines.
This is why recognising and managing sleep apnoea is important. Early assessment can help identify the condition and allow healthcare professionals to recommend suitable treatment.
How Is Sleep Apnoea Diagnosed?
Sleep apnoea cannot be confirmed through snoring or symptoms alone. A healthcare professional needs to assess the person’s symptoms and arrange appropriate testing.
In the UK, the process commonly begins with a GP appointment.
The GP may ask about snoring, daytime sleepiness, breathing interruptions noticed by a partner and other relevant medical conditions. Depending on the assessment, the person may be referred to a specialist sleep service.
A sleep study is used to record breathing patterns and other measurements during sleep.
Depending on the type of test, it may monitor:
- Breathing patterns and airflow.
- Blood oxygen levels.
- Heart rate.
- Breathing effort.
- The number of times breathing stops or becomes unusually shallow.
One commonly used measurement is the Apnoea-Hypopnoea Index (AHI). It represents the average number of apnoeas and hypopnoeas recorded per hour of sleep or monitoring time, depending on the test.
For adults, the usual severity categories are:
| AHI Score | Classification |
|---|---|
| 5–14 events per hour | Mild |
| 15–30 events per hour | Moderate |
| More than 30 events per hour | Severe |
The results help the specialist understand the severity of the condition and decide which treatment may be appropriate.
A sleep study is also important because not every person with snoring or daytime tiredness has obstructive sleep apnoea. Other sleep or medical conditions may produce similar symptoms.
Treatment for Obstructive Sleep Apnoea: What Are the Available Options?
The right treatment depends on the severity of sleep apnoea, the person’s symptoms, medical history and individual circumstances.
The aim is to improve breathing during sleep, reduce symptoms and manage the possible health consequences of the condition.
CPAP is one of the most commonly recommended treatments for obstructive sleep apnoea, particularly in people with moderate or severe symptomatic OSA.
A CPAP machine delivers a steady flow of pressurised air through a tube connected to a mask worn during sleep.
The air pressure helps keep the upper airway open, reducing the likelihood of repeated airway blockages.
- CPAP machine: Produces the prescribed airflow and pressure.
- Mask: Delivers air through the nose or through the nose and mouth.
- Tubing: Connects the machine to the mask.
- Optional humidifier: Adds moisture to the airflow to help reduce dryness and irritation.
Consistent use is important because CPAP works while the device is being worn. Stopping treatment without discussing it with a healthcare professional may allow symptoms to return.
For people who have been prescribed CPAP, comfort matters. An unsuitable mask, air leaks or difficulty adjusting to the airflow can make regular use harder.
Choosing a suitable Treatment obstructive sleep apnoea option should always follow clinical advice and the prescribed therapy requirements.
2. Lifestyle Changes
Lifestyle adjustments can help manage obstructive sleep apnoea, particularly when excess weight or certain habits contribute to the condition.
Depending on individual circumstances, a healthcare professional may recommend:
- Losing excess weight where appropriate.
- Reducing alcohol consumption, especially before bedtime.
- Avoiding smoking.
- Maintaining a regular sleep schedule.
- Avoiding sleeping on the back if positional sleep apnoea is present.
Lifestyle changes can be helpful, but they should not replace prescribed treatment when CPAP or another medical intervention is required.
3. Mandibular Advancement Devices
A mandibular advancement device is a mouthpiece worn during sleep. It gently moves the lower jaw forward to help keep the airway open.
These devices may be considered for some people with obstructive sleep apnoea, particularly those with mild or moderate disease or people who cannot tolerate CPAP.
A dentist or appropriately trained healthcare professional should assess the suitability and fit of the device.
4. Other Medical Treatments
Some people may benefit from other approaches depending on the cause and severity of their sleep apnoea.
These can include:
- Positional therapy for people whose breathing interruptions are mainly associated with sleeping on their back.
- Surgery in selected cases where anatomical factors contribute to airway obstruction.
- Specialist assessment for other airway treatments.
Not every option is suitable for every patient. A sleep specialist can explain the benefits, limitations and potential risks before treatment is selected.
Can CPAP Treatment Improve Heart Health?
CPAP treatment helps manage obstructive sleep apnoea by keeping the airway open during sleep and reducing breathing interruptions.
For some people, effective and consistent CPAP use can improve daytime sleepiness, sleep quality and blood pressure.
These benefits are important, particularly for people who also have cardiovascular risk factors.
However, the relationship between CPAP treatment and long-term cardiovascular outcomes is more complicated.
Although observational studies have identified associations between untreated sleep apnoea and cardiovascular problems, clinical trials have not consistently shown that CPAP prevents heart attacks, strokes or cardiovascular death in every patient group.
The results can depend on factors such as the severity of sleep apnoea, existing health conditions and how consistently the treatment is used.
How Can You Support Better Sleep and Heart Health?
Managing sleep apnoea is only one part of maintaining cardiovascular health. Daily habits and regular medical care also matter.
Here are some practical steps worth discussing with your healthcare professional.
If you have been prescribed CPAP, use it as advised. Contact your sleep clinic or equipment provider if you experience discomfort, persistent air leaks or difficulty using your mask.
Blood pressure, cholesterol and blood glucose monitoring can help identify other cardiovascular risk factors.
Regular physical activity supports general cardiovascular health. Choose an activity that is suitable for your health and fitness level.
A balanced eating pattern can support healthy weight management and reduce some cardiovascular risk factors.
Smoking increases cardiovascular risk and can also irritate the airways.
Alcohol can relax the muscles in the upper airway and may worsen obstructive sleep apnoea in some people, particularly when consumed close to bedtime.
If you continue to feel tired despite spending enough time asleep, or someone notices repeated breathing interruptions, speak to your GP.
Small changes can support better overall health, but they should complement rather than replace appropriate medical treatment.
