15 Facts About Sleep Apnea (How It Impacts Long Term Health and How to Prevent It)

Sleep apnoea is often dismissed as a “social problem”, either a bad habit of “loud snoring” or a tendency to be a “heavy sleeper.” This couldn't be any further from the truth. In fact, it is a sleep-related breathing disorder that acts as a systemic stressor, stimulating the body's 'fight or flight' response, and with potentially devastating long-term cardiovascular and metabolic effects if left untreated. It also affects over 5% of all Australians.

Many people with sleep apnoea are unaware they have this serious medical condition, as it is often first observed by a family member or bed partner. Because it occurs during unconsciousness, a person can stop breathing on several occasions every night and yet never be fully aware of it, leaving many to wonder why they have extreme daytime fatigue.

Good sleep is key to longevity. Unfortunately, proper bedtime hygiene is often insufficient to solve sleep apnoea, just like many other sleep disorders. In this blog, you will learn key facts regarding the physiology of sleep apnoea, the long term impact on health and how regular screening for indicators of systemic health can help you identify the markers of sleep apnoea.

1. Sleep Apnoea is Characterised by Repeated Interruptions to Breathing

Sleep apnoea is defined by these abnormal breathing patterns: repeated “apnoeas” (complete stoppages of breathing) and “hypopnoeas” (partial reductions in breathing rate). Episodes may last from 10 seconds to over a minute.

When breathing stops, blood oxygen levels (oxygen saturation) start to drop (hypoxaemia). At the same time carbon dioxide levels rise. This biochemical change alerts the brain's respiratory control centres to the distress of the body, forcing a “micro-arousal” (a split second return to lighter stages of sleep) to get the throat muscles working again and re-establish airflow. Though life-saving, these arousals prevent the body from getting back to deep, restorative sleep.

Sleep apnoea can affect anyone, including children, but certain factors increase the risk of developing the condition. The underlying causes are complex and can stem from various physical or neurological issues. Unexplained fatigue and mood swings are common symptoms due to interrupted breathing. Furthermore, people with sleep apnoea might wake up with a dry mouth due to breathing with an open mouth. In severe cases, they may also experience significant consequences such as car accidents and lost productivity due to excessive daytime sleepiness.

2. There are Three Types of Sleep Apnoea

The breathing pauses characteristic of sleep apnoea are grouped into three types based on how they happen:

• Obstructive Sleep Apnoea (OSA): Breathing pauses here are the result of a mechanical obstruction. This occurs when the muscles in the back of the throat relax during normal sleep, causing a blockage of the airway. OSA is the most common type. In OSA, the key issue is the relaxation of the muscles that keep the upper airway open during waking. During sleep, particularly during deep sleep stages when there is least muscle tone, these muscles relax. In most people this results in a narrowing of the airway that vibrates (snoring), but for a person with OSA, the airway closes completely. In severe cases, these breathing stops may occur more than 30 times per hour.
  ‍
• Central Sleep Apnoea (CSA): Breathing interruptions in CSA are neurological. The brain fails to signal breathing despite an open airway. Central sleep apnoea is less common than obstructive sleep apnoea.
  ‍
• Mixed/Complex Sleep Apnoea: This is a combination of both obstructive and central types. A person may initially present with OSA but continue to experience interruptions even after treatment clears the physical obstruction.

3. Sleep Apnoea is an Inflammatory Systemic Stressor

One commonly overlooked fact is that sleep apnoea is not simply a problem of the lungs or even the throat. The cycle of repeated drops in oxygen saturation followed by rapid re-saturation (called intermittent hypoxia) physiologically recreates what is known as “reperfusion injury”, generating reactive oxygen species (ROS) and causing oxidative stress. This leads to systemic inflammation which is sometimes detectable as the blood marker high-sensitivity C-reactive protein (hs-CRP).

4. Sleep Apnoea and Metabolism

There is a bi-directional relationship between sleep apnoea and metabolism. Intermittent hypoxia disrupts glucose metabolism. Studies suggest that sleep apnoea contributes to insulin resistance, making it harder for your body to use available sugar to create energy and raising blood sugar levels. This often manifests as rising levels of glycated haemoglobin (HbA1c). Monitoring fasting insulin is also important to check for underlying resistance and ensure energy intake (measured in kilojoules) is metabolised effectively.

5. OSA Impacts Heart Health

One detrimental effect of untreated OSA is hypertension (high blood pressure). Each time blood oxygen levels drop, the sympathetic nervous system triggers an aggressive response due to oxygen starvation. Blood pressure suddenly spikes as levels of adrenaline and cortisol surge. Over time this raises your body’s natural “set point” for blood pressure, resulting in chronic hypertension that can be resistant to normal medications. This increases the cumulative risk for:

• Atrial Fibrillation
• Heart Failure
• Ischaemic Heart Disease
• Stroke

6. Impact on Brain Function: Cognition & Mood

The brain is highly sensitive to oxygen levels. Chronic drops are associated with executive dysfunction, memory problems during long-term data retention, and increased irritability. Chronic inflammation from repeated micro-arousals may even accelerate beta amyloid accumulation, which is a plaque marker for neurological decline.

7. Impact on Hormones: Testosterone & Growth Hormone

Deep sleep helps regulate testosterone production and growth hormone release. Most testosterone production in men occurs during the first rounds of deep, slow-wave sleep. Sleep apnoea disrupts this natural rhythm, which can lead to low testosterone symptoms like low libido. Growth hormone, which helps maintain muscle mass and blunts fat accumulation, is also triggered by deep sleep cycles. Disrupted sleep thus leads to increased body fat and lower recovery rates from exercise.

8. Many Cases Go Undetected

Many Australians living with moderate to severe apnoea remain undiagnosed. Affected individuals feel like they’ve slept all night but wake up with chronic fatigue. One frequently overlooked sign is “nocturia”, which is the need to wake frequently at night to urinate. When the heart is under strain during an apnoea event, it releases Atrial Natriuretic Peptide (ANP), a hormone that causes the kidneys to produce more urine. Frequent night-time urination can be a clinical hint that points towards sleep apnoea.

9. Not All Patients Fit The Profile

While a large neck circumference (over 43cm for men, 40cm for women) is a primary factor for OSA, it can affect anyone. Factors such as a recessed jaw, large tonsils, a deviated septum or an inherently narrow airway can cause OSA in apparently fit and lean individuals. This is why a thorough clinical look at your physical health is essential.

10. The Apnea-Hypopnea Index (AHI)

To quantify severity, clinicians use the Apnoea-Hypopnoea Index (AHI), expressed as the average number of events per hour:

• Normal: Less than 5 events per hour
• Mild OSA: 5 to 15 events per hour
• Moderate OSA: 15 to 30 events per hour
• Severe OSA: More than 30 events per hour

11. Diagnosis via Polysomnography

Doctors diagnose sleep apnoea using medical history, physical examination, and a sleep study. A Sleep Study (Polysomnography) provides gold-standard data because it monitors brain wave activity, oxygen saturation, and chest efforts to distinguish between central and obstructive sleep apnoea. While home sleep testing is gaining popularity, polysomnography remains a vital investigation for a formal diagnosis.

12. Evidence-Based Treatments

• CPAP Therapy: Continuous Positive Airway Pressure (CPAP) is an evidence-based treatment for moderate to severe OSA. It prevents airways from collapsing by blowing pressurised air via a nasal mask. Research shows effective use reduces daytime tiredness and lessens the risk of cardiovascular disease.
• Oral Appliances and Surgery: For mild to moderate cases, a Mandibular Advancement Splint (MAS) may be used to push the jaw forward and keep the airway open. Surgical options are generally reserved for patients with specific anatomical abnormalities who cannot tolerate other therapies.

13. Lifestyle Changes

Weight management is an important means to manage or reduce the risk of OSA. Excess tissue around the neck and chest exerts mechanical pressure on the airway. Adopting a diet with appropriate kilojoule (kJ) targets can assist. Other helpful changes include avoiding alcohol and sleeping pills before bed and adopting a sideways sleeping position.

14. Proactive Screening

OSA is often a progressive condition. Throat tissues can lose tone with age, making the symptoms worse over time. Early detection is critical. Clinical screening can address your sleep health within the context of your overall wellbeing. Screening for inflammatory, metabolic and cardiovascular markers can identify issues early so they can be managed effectively alongside formal diagnostic pathways.