Introduction

Sleep apnoea is a disorder in which the affected person experiences recurrent obstructions of the airways during their sleep. This causes a reflex response whereby the body wakes up so that the person may breathe. This results in a poor quality of sleep, which may, in turn, lead to other health problems. One of the tell-tale signs of this condition is snoring loudly in your sleep and daytime sleepiness. This disorder could be life-threatening if not diagnosed and treated accordingly. In serious cases, this disease could lead to cardiovascular diseases such as hypertension and diabetes.

Sleep apnoea is a common condition, with individuals assigned male at birth (AMAB) being the most affected. This article will take you through the pathology of sleep apnoea and also explore the effects of this condition on nocturnal sweating and respiratory health.

Unpacking sleep apnoea

There are 3 types of sleep apnoea, namely obstructive sleep apnoea (OSA), central sleep apnoea (CSA) and treatment-emergent central sleep apnoea (TECSA).^1,2 OSA accounts for most sleep apnoea cases. It is caused by the relaxation of muscles in the throat, which affects the flow of air within the airways. CSA results from a malfunction in the central nervous system, causing the muscles that control breathing to be affected during sleep.³ With treatment-emergent central sleep apnoea, an individual who is undergoing treatment for OSA may then develop CSA.¹ Treatment-emergent sleep apnoea is also referred to as mixed or complex sleep apnoea.

Sleep apnoea may also be referred to under the term obstructive sleep apnoea-hypopnoea syndrome (OSAHS). OSAHS is an umbrella term that describes sleep apnoea and hypopnoea, which are both conditions in which breathing is affected during sleep. The key difference between sleep apnoea and hypopnoea is that in sleep apnoea, the breathing is completely blocked, whilst this blockage is only partial in hypopnoea.⁴ Both sleep apnoea and hypopnoea are characterised by breathing obstructions of about 10 seconds whereby you get awakened so that you may take a breath.⁴ This occurs subconsciously, so affected persons are unaware that they keep on getting awakened during their sleep. In severe cases, these episodes of breathlessness can occur up to 30 times within an hour. This means that the people living with sleep apnoea are unable to get into a consistent phase of deep sleep, thereby forfeiting the replenishment and nourishment that comes with it.

Signs and symptoms of sleep apnoea

• Loud snoring
• Moments in which the affected person is observed to be not breathing during their sleep
• Hypersomnia, whereby the affected person is sleepy during the day, usually more severe in people with CSA⁵
• Having difficulties concentrating as well as a loss of memory
• Fatigue, despite having had a full night of sleep, is usually more severe in people with CSA
• Experiencing feelings of depression or anxiety
• Waking up due to feeling like you are choking
• Morning headache and dry mouth
• In cases of CSA, affected individuals may also have unusual breathing patterns. This unusual breathing pattern is referred to as nighttime perspiration³

Risk factors

When it comes to risk factors, they may differ for OSA and CSA. However, there are some common risk factors between the 2 types of sleep apnoea. Older people and those AMAB are more likely to develop sleep apnoea.⁶

Obstructive sleep apnoea

• Having a thick neck
• Being overweight
• Alcohol consumption and smoking
• Taking sedatives and tranquillisers
• Living with medical conditions such as type 2 diabetes and hypertension

Central sleep apnoea

• Heart failure
• Using opioids
• People who have suffered a stroke may also have CSA

Complications that could arise due to sleep apnoea

These are some of the diseases that are associated with sleep apnoea:⁷

• Hypertension
• Diabetes
• Heart disease
• Stroke 
• Dementia
• Metabolic syndrome
• Early death

The effects of sleep apnoea on respiratory health

In addition to the blockages in the airways during sleep, other respiratory issues could arise in people living with sleep apnoea. Sleep apnoea may also overlap with other respiratory diseases or exacerbate them. Inversely, other respiratory diseases may also lead to sleep apnoea.⁸

Respiratory acidosis and metabolic alkalosis

One of the associated complications is respiratory acidosis. In respiratory acidosis, there is an increase in the levels of carbon dioxide. The accumulation of carbon dioxide in the blood is referred to as hypercapnia. What respiratory acidosis then leads to is a build-up of bicarbonate in the bloodstream. This is known as metabolic alkalosis whereby the kidneys expel hydrogen ions whilst keeping bicarbonate ions in the bloodstream.⁹

People with respiratory acidosis breathe slowly and. Individuals could also experience headaches and confusion. This condition also causes an increase in heart rate. Cyanosis is also one of the tell-tale signs of respiratory acidosis, whereby affected individuals have blue lips and skin.

Pulmonary hypertension

Increased carbon dioxide levels in the blood mean that the levels of oxygen will be reduced to bring about hypoxia. This causes more blood to be pumped to the lungs to meet the body’s oxygen demands. However, this places a lot of pressure on the blood vessels of the lung, as it may cause them to narrow. The eventual consequence of increasing blood supply to the lungs is pulmonary hypertension whereby the blood pressure in pulmonary blood vessels is increased.¹⁰

Other respiratory conditions

Sleep apnoea has been associated with respiratory diseases that include asthma.⁸ It is thought that asthma may be a risk factor in the development of sleep apnoea. On the other hand, sleep apnoea is also implicated in the worsening of asthma symptoms. The co-occurrence of sleep apnoea and COPD is referred to as the overlap syndrome. Even though the name of the condition suggests that sleep apnoea and COPD have common manifestations, they are different diseases as COPD is the chronic inflammation of the airways.⁸ Sleep apnoea is also linked to bronchiectasis whereby the airways dilate to result in a lot of mucus being produced.⁸

How sleep apnoea can cause nighttime sweating

Patients of sleep apnoea often experience nighttime sweating. The sweating is more pronounced in the neck and the upper regions of the body.¹¹ The wake and sleep episodes in sleep apnoea are said to induce a state of fight or flight, which is controlled by the.¹² Fight or flight, which is usually described as the fight or flight response, is activated when the body senses danger, sweating being one of the physical manifestations of this phenomenon. The decrease in oxygen levels due to breathing obstructions is also implicated in night sweating.¹³

Diagnosis and management of sleep apnoea

To diagnose sleep apnoea, a polysomnography or a home sleep test is performed. With a polysomnograph the patient is monitored in a medical facility, whereby they measure various parameters during sleep. These parameters include monitoring brain activity, breathing, heart rate and oxygen levels. A home sleep test is usually used to observe breathing patterns during sleep as well as the heart rate and oxygen levels. The home sleep test does not include monitoring brain activity, and it is also not useful for CSA or severe OSA.

The management of sleep apnoea includes lifestyle changes as well as undergoing medical treatment. These lifestyle changes include weight loss as well as adopting a healthier lifestyle in the form of reducing alcohol intake, smoking and altering your sleeping position. Obesity has been linked to increases in fat in the tongue and pharynx, which then leads to airway obstruction.¹⁴ Medical intervention includes the surgical removal of enlarged tonsils and adenoids from sleep apnoea patients. Treating sleep apnoea entails using the continuous positive airway pressure (CPAP) machine. During sleep, the device is connected to a face mask and applies air pressure that ensures that the airways stay open.

FAQs

Does sleep apnoea cause you to sweat excessively?

People suffering from sleep apnoea tend to have night sweats, especially if it is not being managed with treatment.

Does sleep apnoea lead to respiratory problems?

As a result of repeated blockages of airflow during sleep, people living with sleep apnoea may experience respiratory distress, such as shallow or slow breathing.

How can sleep apnoea impact your body?

Sleep apnoea is linked to other serious health conditions such as diabetes, strokes and heart attacks.

What leads to respiratory acidosis in sleep apnoea patients?

People with sleep apnoea can have their blood carbon dioxide levels increased, resulting in respiratory acidosis.

Summary

In sleep apnoea, a person may have their breathing obstructed numerous times during sleep. It is a common disorder that affects a lot of people. The most common symptoms are loud snoring and interruptions of breathing during sleep. The breathing disruptions lead to a reduced quality of sleep, which is why sleep apnoea patients also experience daytime sleepiness. Since breathing is affected, people with sleep apnoea may also have low levels of oxygen in their blood. Sleep apnoea may lead to serious health complications, which include a stroke, heart attack and diabetes. The respiratory system is also affected by this disorder. People with sleep apnoea may also experience breathing difficulties such as slow and shallow breaths. The blood vessels in the lungs are also placed under a lot of pressure. Another common effect of sleep apnoea is nighttime sweating. To diagnose this condition, the patient’s sleep is monitored under medical supervision or at home. To manage the disease, affected people are encouraged to make healthier lifestyle choices such as losing weight and decreasing alcohol intake and smoking. In some cases, the continuous positive airway pressure (CPAP) treatment may be administered to keep airways open during sleep.