The causes of sleep apnea almost all come back to an airway that collapses too easily while you sleep. Excess weight is the best-known factor, but neck circumference, the shape of your jaw and throat, evening alcohol and a number of medicines all play a part. Some of those factors you can change, others you were simply born with.
That distinction is what I miss on most pages about this subject.
They list risk factors without saying which ones you can act on. Which is the only question that matters to you. So below, for each factor, what it does and whether you can turn the dial.
What is the main cause of sleep apnea?
Excess weight is the strongest modifiable cause. Fat around the neck presses on the airway from outside, and belly fat pushes against your diaphragm when you lie down, so your lungs expand less and the airway stays less stable. Both effects arrive during sleep, when your throat muscles are already relaxed.
Neck circumference predicts better than the number on the scales. In men, roughly 43 centimetres upward is treated as raised risk. Take two men who both weigh 95 kilos: one carries a neck circumference of 39 centimetres and the other 46, and the second faces clearly higher odds purely through where his body puts the fat.
That it is modifiable is more than theory. Kuna and colleagues followed people with obesity and type 2 diabetes for four years in the Sleep AHEAD study. The group on an intensive lifestyle programme maintained a lower apnea-hypopnea index than the control group, and the effect tracked how much weight actually stayed off.
How to tackle that belly fat without ignoring the hormonal side is covered in losing belly fat as a man.
Why do men get sleep apnea more often than women?
Men have a longer throat, a narrower passage and different muscle tone in the upper airway during sleep. On top of that, men store fat around the neck and belly sooner than around hips and thighs. That combination explains the gap in almost every population study.
The figures are not subtle. In the HypnoLaus study, 49.7 percent of men aged 40 to 85 had a moderate to severe form, against 23.4 percent of women.
Age stacks on top. Risk climbs until around sixty and levels off after that, which means the years when your career and family are busiest are exactly the years when the odds rise fastest.
Which other risk factors are there?
Beyond weight and sex, a handful of other things count. The table below sets them out, with why each matters and whether you can change it yourself. That last column is the point of this article.
| Factor | Why it counts | Modifiable? |
|---|---|---|
| Excess weight and belly fat | Presses the airway closed and reduces lung volume when lying down | Yes |
| Neck circumference above 43 cm | More tissue around an airway that is already narrow | Partly, through weight |
| Alcohol in the evening | Relaxes the throat muscles exactly when you need them | Yes |
| Smoking | Irritates the airway lining and makes it swell | Yes |
| Sleeping on your back | Gravity pulls the tongue backwards | Yes |
| Receding or small lower jaw | Permanently reduces the space behind the tongue | No |
| Large tonsils or deviated septum | Narrows the passage higher up the airway | Sometimes, surgically |
| Age and sex | Tissue slackens over the years, male anatomy is more vulnerable | No |
Look at that right-hand column and the majority of factors turn out to be modifiable. That is a more agreeable conclusion than most people expect when they land on this subject.
Which conditions raise the odds of sleep apnea?
An underactive thyroid is the best known. In hypothyroidism, tissue in the throat can retain fluid and swell, and the condition also produces the fatigue and sluggishness that resemble apnea. That makes it doubly relevant: as an aggravating factor and as a confusing diagnosis.
Sleep apnea also associates with high blood pressure, type 2 diabetes and heart rhythm disorders. That link runs both ways. Peppard and colleagues showed in the New England Journal of Medicine in 2000 that the odds of new high blood pressure rose with apnea severity, even after correcting for weight and age.
The Dutch Heart Foundation, Hartstichting, accordingly lists sleep apnea among the things associated with high blood pressure and rhythm disorders. With blood pressure that will not come down despite medication, it is one of the things a doctor can bring in.
What your thyroid has to do with this is in thyroid health in men. The blood pressure side is in high blood pressure in men.
Can medication make sleep apnea worse?
Yes, several drugs can affect breathing during sleep unfavourably. Sleeping tablets from the benzodiazepine group and strong painkillers from the opioid group relax the muscles and blunt the drive to breathe. That is precisely the wrong combination for an airway that already collapses too easily.
Testosterone from outside belongs on this list too, and for our readers it is the most relevant one. Hoyos and colleagues gave eighteen weeks of testosterone to men with obesity and severe sleep apnea in 2012. Breathing during sleep measurably worsened in the early weeks, though that difference was no longer significant at eighteen weeks.
This is not a reason to stop anything on your own. It is a reason to mention that you snore or fade out during the day when you talk to your doctor about testosterone therapy. What else is involved there is covered in TRT explained.
What can blood testing actually establish?
Blood does not demonstrate sleep apnea. What blood does do is make visible the conditions that mimic the complaints or aggravate the apnea: an underactive thyroid, an iron deficiency, disordered blood sugar and low testosterone.
That is exactly why many men end up here. The complaint is fatigue, the first step is a blood test, and the outcome decides whether the next conversation is about hormones or about breathing.
For a broad picture there is the male hormone panel. What gets measured is set out on the marker pages for TSH and total testosterone.
What it comes down to
The causes of sleep apnea are part anatomy and part lifestyle, and the good news is that the lifestyle side weighs more heavily than people assume. Weight, alcohol, smoking and sleeping position are all four in your own hands.
What strikes me here is how often medication stays out of the conversation. Sleeping tablets and testosterone are rarely mentioned when someone reports that their snoring has got worse over recent months.
If you recognise several factors from the table, raise it with your doctor and ask about a sleep study. What that looks like is in sleep study. The full picture is in the pillar on sleep apnea in men.
Every blood test result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.
References
- Heinzer R, et al. Prevalence of sleep-disordered breathing in the general population: the HypnoLaus study. The Lancet Respiratory Medicine, 2015. PMID 25682233
- Kuna ST, et al. Long-term effect of weight loss on obstructive sleep apnea severity in obese patients with type 2 diabetes. Sleep, 2013. PMID 23633746
- Peppard PE, et al. Prospective study of the association between sleep-disordered breathing and hypertension. New England Journal of Medicine, 2000. PMID 10805822
- Hoyos CM, et al. Body compositional and cardiometabolic effects of testosterone therapy in obese men with severe obstructive sleep apnoea. European Journal of Endocrinology, 2012. PMID 22848006
Author
Caliberhealth
Dr. Naimi, BIG-registered physician, oversees the medical standards behind our content and assessments. Read our medical policy
