Respiratory and Sleep Apnea

In the short term, untreated sleep apnea makes sufferers sleepy, accident-prone, and
hypertensive. In the long run, this sleep disorder can leave you with heart disease and
metabolic problems, among many other health issues [1].
While many are now familiar with the above consequences of untreated sleep apnea, there is
surprisingly little mention of its effects on the respiratory system. Sleep apnea is a breathing
disorder, after all. It should have some effects on the lungs and other respiratory organs, right?

Effects of Sleep Apnea on the Respiratory System
Obstructive sleep apnea (OSA) is a sleep-related breathing disorder. It causes repeated pauses
in breathing during sleep, which results in fragmented sleep and low blood oxygen levels.
Virtually every organ system is affected by these changes, most notably the brain and heart.
However, there is another problem that occurs during apneic episodes that may affect the lungs
and that is intrathoracic pressure swings [2]. During normal breathing, the pressure inside your
chest cavity is negative, which facilitates lung inflation and normal blood flow. During apneic
episodes, there are swings between positive and negative pressure, which some researchers
believe could damage lung tissue [3].
Researchers suspect that sleep apnea may cause other respiratory issues or worsen existing
ones through multifaceted and complex mechanisms. But this has not yet proven to be true as
more research is needed to understand the link between sleep apnea and respiratory problems.
Respiratory Problem Linked to Sleep Apnea
As explained, sleep apnea may cause or worsen existing lung conditions. Three respiratory
problems most frequently linked to sleep apnea are:

Pulmonary Hypertension

Roughly 20% of people with OSA have pulmonary hypertension [4]. Pulmonary hypertension is
a type of high blood pressure affecting lung arteries and the right side of the heart. Drops in
blood oxygen levels that happen during apnea episodes trigger constrictions of blood vessels.
Besides that, changes in lung pressure with apneic episodes may be another contributing factor.

Asthma
Asthma and OSA often co-occur, which makes treatment of both more difficult [2]. Sleep apnea
Apneic episodes can increase smooth muscle tone and worsen bronchoconstriction in asthma
sufferers. Changes in blood flow and oxygen levels that happen in the lungs of OSA sufferers
can cause changes in the lower airways that make asthma more difficult to treat.

OSA-COPD Overlap Syndrome
Chronic obstructive pulmonary disease (COPD) and OSA can also co-occur in some patients,
which is known as overlap syndrome. When patients have both conditions, there’s a greater risk
of disability and early death.
COPD is a chronic and progressive inflammatory lung disease that causes trouble with normal
breathing. The most common cause is smoking, with air pollutants being another possible
cause. When these conditions co-occur with sleep apnea, treatment tends to be more difficult
and the outcomes grim.
References:

1. Jordan AS, McSharry DG, Malhotra A. Adult obstructive sleep apnoea. Lancet. 2014 Feb
22;383(9918):736-47. doi: 10.1016/S0140-6736(13)60734-5. Epub 2013 Aug 2. PMID:
23910433; PMCID: PMC3909558.

2. Locke BW, Lee JJ, Sundar KM. OSA and Chronic Respiratory Disease: Mechanisms and
Epidemiology. Int J Environ Res Public Health. 2022 Apr 30;19(9):5473. doi:
10.3390/ijerph19095473. PMID: 35564882; PMCID: PMC9105014.

3. Lederer DJ, Jelic S, Bhattacharya J, Basner RC. Is obstructive sleep apnea a cause of
idiopathic pulmonary fibrosis? Arch Pathol Lab Med. 2012 May;136(5):470; author reply
470. doi: 10.5858/arpa.2011-0650-LE. PMID: 22540293; PMCID: PMC7213593.

4. Shah FA, Moronta S, Braford M, Greene N. Obstructive Sleep Apnea and Pulmonary
Hypertension: A Review of Literature. Cureus. 2021 Apr 20;13(4):e14575. doi:
10.7759/cureus.14575. PMID: 34035997; PMCID: PMC8135661.