Sleep Apnoea Is More Than Snoring: Risks, TRT, Weight, Genetics and the Bigger Health Picture

There is a tendency to reduce sleep apnoea to one symptom:

Snoring.

But obstructive sleep apnoea can reach far beyond what happens during the night.

Repeated interruptions to breathing can fragment sleep, lower oxygen levels and repeatedly activate the body’s stress response. Over time, untreated obstructive sleep apnoea is associated with cardiovascular, metabolic and cognitive consequences that make it worth looking at as part of the wider health picture – not simply as a sleep problem.

And while weight is one of the better-known risk factors, it isn’t the only one.

Genetics. Airway anatomy. Age. Alcohol. Certain health conditions. And, in some people, considerations around testosterone replacement therapy can all influence risk.

So, what actually is sleep apnoea – and who should be paying attention?

 

 

What is Obstructive Sleep Apnoea?

 

Obstructive sleep apnoea, often shortened to OSA, occurs when the upper airway repeatedly narrows or closes during sleep.

When airflow reduces, it is described as a hypopnoea.

When breathing temporarily stops, it is an apnoea.

The brain responds by bringing you into a lighter stage of sleep or briefly waking you enough to reopen the airway. You may have no memory of this happening.

But your body does.

These episodes can happen repeatedly throughout the night, resulting in fragmented sleep and, in some people, repeated falls in blood oxygen saturation.

That is why somebody can technically spend eight hours in bed and still wake up feeling as though they have barely slept.

 

 

Sleep apnoea symptoms aren’t always obvious

 

Loud snoring and witnessed pauses in breathing are two of the most recognisable features, but they are not the whole picture.

NICE recommends considering obstructive sleep apnoea where someone has two or more features including:

• Loud or persistent snoring
• Witnessed pauses in breathing
• Choking or gasping during sleep
• Unrefreshing sleep
• Waking headaches
• Unexplained daytime sleepiness
• Persistent tiredness or fatigue
• Waking frequently to urinate
• Disrupted sleep or insomnia
• Problems with concentration, memory or cognition.

 

Importantly, not everyone with sleep apnoea feels excessively sleepy.

That matters because someone experiencing fatigue, poor concentration, headaches or disrupted sleep may not immediately recognise sleep apnoea as a possibility.

 

 

Why does Sleep Apnoea matter?

 

It isn’t the sound of snoring that makes obstructive sleep apnoea medically important.

It is what repeated airway obstruction can do beneath the surface.

Each episode can create a combination of:

airway obstruction → reduced airflow → falling oxygen → arousal from sleep → restoration of breathing

before the process begins again.

Repeated intermittent hypoxia, sleep fragmentation and activation of the sympathetic nervous system can place additional stress on cardiovascular and metabolic regulation. Obstructive sleep apnoea is associated with conditions including hypertension, atrial fibrillation, cardiovascular disease, stroke and type 2 diabetes.

Untreated sleep apnoea can also contribute to:

• Impaired concentration and cognitive performance
• Poor daytime energy
• Mood disturbance
• Reduced quality of sleep
• Impaired work performance
• Excessive daytime sleepiness
• Increased accident risk where tiredness affects driving or other safety-critical activities.

Sleep isn’t passive.

It is one of the foundations your cardiovascular, neurological, endocrine and metabolic systems rely on.

 

 

What increases the risk of sleep apnoea?

 

There is rarely one single explanation.

Sleep apnoea is better understood as the result of multiple overlapping risk factors influencing airway structure, airway stability and breathing during sleep.

 

 

1. Weight and body composition

 

Being overweight or living with obesity is one of the strongest recognised risk factors for obstructive sleep apnoea.

Additional tissue around the neck and upper airway can contribute to airway narrowing, while central adiposity can also affect respiratory mechanics.

But there is an important distinction:

Weight is a risk factor for sleep apnoea. It is not a requirement for having it.

A lean individual can still develop significant OSA because anatomy, genetics, airway function and other factors matter too.

Equally, not everyone living with obesity will have sleep apnoea.

This is why symptoms and individual risk factors need to be assessed in context rather than assuming someone’s BMI gives us the whole answer. NICE recognises overweight and obesity as factors associated with a higher prevalence of OSA and recommends appropriate weight-management support as part of management where relevant.

 

 

2. Genetics and family history

 

Sleep apnoea can run in families.

And that isn’t simply because families can share similar body weights or lifestyle factors.

Inherited characteristics can influence:

• Jaw and craniofacial structure
• Tongue and upper-airway soft tissue
• Fat distribution
• Airway collapsibility
• Respiratory control during sleep.

International consensus evidence suggests that having a first-degree family member with obstructive sleep apnoea is associated with approximately twice the risk of developing OSA yourself.

More recent large-scale genetic research also supports a genuine polygenic component to OSA susceptibility, including genetic influences that remain after accounting for BMI.

So, when somebody says:

“My dad has sleep apnoea, but I’m not overweight.”

That family history is still relevant.

 

 

3. Your individual airway anatomy

 

Some people simply have an airway that is more vulnerable to obstruction when muscle tone reduces during sleep.

Potential anatomical contributors include:

• A relatively small or recessed lower jaw
• A larger tongue
• Enlarged tonsils
• A narrower upper airway
• Craniofacial structure
• Nasal obstruction.

These structural differences can exist regardless of body weight.

This is one of the reasons why sleep apnoea should never be viewed solely as a weight-related condition.

 

 

4. Age and Sex

 

OSA becomes more common with age and historically has been diagnosed more frequently in men.

Hormonal influences, differences in airway anatomy and differences in patterns of body-fat distribution are likely to contribute.

But women absolutely develop obstructive sleep apnoea too – and symptoms do not always present as the stereotypical picture of a man with very loud snoring and profound daytime sleepiness.

Fatigue, insomnia, headaches, poor concentration and fragmented sleep can all form part of the clinical picture.

 

 

TRT and sleep apnoea: what’s the connection?

 

This is where context matters.

Testosterone replacement therapy does not automatically cause sleep apnoea.

But there is enough evidence of a potential relationship between testosterone therapy and sleep-disordered breathing that it should not be ignored – particularly where someone already has significant risk factors or symptoms of OSA.

Research examining TRT and obstructive sleep apnoea remains relatively limited and findings have not been completely uniform.

However, clinical trials have shown that testosterone therapy can temporarily worsen measures of nocturnal oxygen desaturation and sleep-disordered breathing in some men with existing severe OSA.

Current Endocrine Society guidance recommends against starting testosterone therapy in men with untreated severe obstructive sleep apnoea.

That does not mean every man considering TRT requires a sleep-apnoea diagnosis.

It does mean that symptoms such as:

• Loud snoring
• Witnessed breathing pauses
• Gasping during sleep
• Persistent morning headaches
• Unexplained daytime fatigue
• Excessive sleepiness

should not be overlooked simply because low testosterone has already been identified.

There can also be an important bidirectional relationship here.

Poor sleep, obesity, repeated hypoxia and sleep fragmentation can themselves sit alongside lower testosterone concentrations and symptoms commonly attributed to testosterone deficiency.

So fatigue, poor recovery, low mood and reduced libido should not automatically be interpreted through one hormone marker alone.

The wider clinical picture still matters.

 

 

Sleep apnoea, TRT and Haematocrit

 

There is another reason the TRT conversation deserves context: red blood cell production.

Testosterone therapy can increase haemoglobin and haematocrit in some individuals.

At the same time, repeated nocturnal hypoxia in severe OSA may provide an additional stimulus for red blood cell production.

A systematic review found that people with obstructive sleep apnoea had slightly higher haematocrit levels overall, particularly in severe OSA, although the average increase was modest and OSA alone did not usually produce clinically significant erythrocytosis.

So a raised haematocrit should not simply be labelled:

“It’s the sleep apnoea.”

Or:

“It’s the testosterone.”

It needs investigation in context.

For someone using TRT who also has symptoms suggestive of OSA, both pieces of information can be clinically relevant.

 

Alcohol, Sedatives and sleeping position

 

Anything that further relaxes the muscles supporting the upper airway may make obstruction more likely in susceptible people.

Alcohol – particularly close to bedtime – can worsen OSA in some individuals.

Sleeping tablets and other sedating medicines may also worsen sleep-disordered breathing and should only be used as medically advised in somebody with known or suspected sleep apnoea.

For some people, OSA is also substantially worse when sleeping on their back.

Again, these may not be the fundamental cause of OSA.

They can be co-factors that amplify an existing vulnerability.

 

What other health conditions are associated with sleep apnoea?

 

NICE identifies a higher prevalence of obstructive sleep apnoea among people with several medical conditions, including:

• Treatment-resistant hypertension
• Type 2 diabetes
• Atrial fibrillation and other cardiac arrhythmias
• Previous stroke or transient ischaemic attack
• Chronic heart failure
• Hypothyroidism
• Acromegaly
• Moderate or severe asthma
• Polycystic ovary syndrome.

This doesn’t necessarily mean one condition directly caused the other.

It means the overlap is significant enough that the possibility of OSA should form part of appropriate clinical assessment.

 

 

Can a blood test diagnose sleep apnoea?

 

No.

And this distinction is important.

You cannot diagnose obstructive sleep apnoea from a testosterone result, cortisol result, full blood count or any other blood marker.

If OSA is suspected, NICE recommends home respiratory polygraphy as the initial diagnostic test for adults, with other sleep-testing approaches considered depending on symptoms, availability and the clinical picture.

However, blood testing can still provide useful information about the wider physiological picture surrounding someone’s symptoms and risk factors.

Depending on the individual, relevant markers could include:

 

Full blood count

Particularly haemoglobin and haematocrit.

This can be especially relevant in somebody taking testosterone therapy because TRT itself can increase red blood cell production.

 

HbA1c and glucose markers

OSA frequently overlaps with insulin resistance, obesity and type 2 diabetes.

Testing does not diagnose OSA, but it can identify metabolic factors that may need addressing alongside it.

 

Lipid profile

Given the overlap between obstructive sleep apnoea and cardiovascular risk, cholesterol and triglycerides can help provide additional cardiovascular context.

 

Thyroid markers

Hypothyroidism is associated with a higher prevalence of OSA and can independently produce symptoms such as fatigue, weight change and poor concentration.

Where clinically appropriate, TSH and free thyroid hormone assessment may therefore provide useful additional context.

 

Testosterone and reproductive hormones

Where symptoms genuinely suggest testosterone deficiency, hormonal testing can be useful.

But a single low testosterone result should never automatically explain fatigue, low energy, poor recovery or reduced libido without considering sleep quality, weight, medication, stress and other health factors.

 

Blood pressure

It isn’t a blood test – but it deserves a place on the list.

Obstructive sleep apnoea and hypertension frequently coexist, and OSA should be particularly considered in treatment-resistant or poorly controlled hypertension.

 

 

So, when should you investigate sleep apnoea?

 

Snoring occasionally does not automatically mean you have OSA.

But it becomes much harder to dismiss when several pieces begin appearing together.

For example:

snoring + witnessed breathing pauses + morning headaches

or

unrefreshing sleep + daytime fatigue + high blood pressure

or

TRT + rising haematocrit + new loud snoring/daytime sleepiness

or

family history + compatible symptoms despite a healthy body weight.

 

Those patterns deserve a proper conversation.

NICE advises assessment for OSA where two or more recognised features are present and recommends tools such as the Epworth Sleepiness Scale and STOP-Bang Questionnaire as part of preliminary assessment – although neither questionnaire should replace a diagnostic sleep study.

 

 

How is obstructive sleep apnoea treated?

 

Treatment depends on the severity of OSA, symptoms and the factors contributing to it.

This can include:

• Weight management where appropriate
• Reducing alcohol intake
• Stopping smoking
• Improving sleep habits
• Positional therapy in selected cases
• Mandibular advancement devices
• Managing nasal obstruction
• Continuous positive airway pressure therapy, better known as CPAP.

NICE recommends CPAP alongside lifestyle advice for people with moderate or severe OSA and for some people with symptomatic mild disease.

The right intervention depends on the individual – not simply the number of times they snore.

 

The My Atlas perspective

 

One abnormal marker rarely tells the whole story.

And neither does one symptom.

If somebody is fatigued, struggling with recovery, experiencing changes in body composition or investigating their hormones, there can be a temptation to focus entirely on what appears on the blood report.

But physiology doesn’t operate marker by marker.

Sleep quality influences the environment those markers sit within.

Likewise, metabolic health, body composition, hormones, cardiovascular health, medication and genetics can all provide important context around sleep.

At My Atlas, our role is to help you investigate that wider health picture through appropriate biomarker testing and clinical interpretation.

Blood testing cannot diagnose sleep apnoea.

But where symptoms point towards OSA, recognising the possibility — rather than trying to explain everything through a testosterone result, thyroid marker or body weight – can be an important next step.

Because good health isn’t simply about how many hours you spend in bed.

It is about what your body is doing during them.

 

Frequently Asked Questions (FAQs)

 

Can you have sleep apnoea if you aren’t overweight?

 

Yes. Obesity is an important risk factor, but lean individuals can develop OSA due to factors such as airway anatomy, craniofacial structure, age, family history and inherited susceptibility.

 

 

Can testosterone replacement therapy cause sleep apnoea?

 

The relationship is not that straightforward.

TRT does not inevitably cause OSA, but available evidence suggests it can worsen sleep-disordered breathing in some susceptible men.

Current Endocrine Society guidance recommends against starting testosterone therapy where severe OSA remains untreated.

 

Can sleep apnoea cause high haematocrit?

Severe OSA has been associated with modest increases in haematocrit, likely related to intermittent hypoxia.

However, evidence suggests OSA alone does not usually produce clinically significant erythrocytosis, so a substantially raised haematocrit should still be properly investigated.

 

 

Can sleep apnoea lower testosterone?

 

OSA and lower testosterone can coexist, particularly alongside obesity and metabolic dysfunction.

Sleep fragmentation and intermittent hypoxia may contribute, but the relationship is multifactorial and a low testosterone result should be interpreted within the wider clinical picture.

 

 

What test confirms sleep apnoea?

 

A sleep study is required to diagnose obstructive sleep apnoea. NICE recommends home respiratory polygraphy as the first-line diagnostic investigation for suspected OSA in adults.

 

Medical disclaimer:

This article is for educational purposes and does not replace individual medical assessment. If you are concerned about sleep apnoea, particularly if you experience witnessed pauses in breathing, choking during sleep or excessive daytime sleepiness, speak to your GP or an appropriate sleep service. Do not start, stop or alter prescribed testosterone therapy or other medication without discussing this with the clinician responsible for your care.