What's Keeping a Billion People Up at Night?

Breathing has been described by top scientists as “important” for some reason. Unfortunately, some of us have trouble breathing at night, which is… less than ideal. Obstructive sleep apnea (OSA) is a condition where the airway is periodically blocked while sleeping, leading to sleep disruptions. The word apnea comes from the Greek language. The prefix  a- means “not” and -pnea comes from the word for breath, the same root as the word “pneumatic.” OSA is very common, with around one billion people suffering from the condition worldwide. Most people are unaware they have OSA because the breathing interruptions occur when sleeping. Regardless, OSA can cause people to snore, wake up at night, and have sleep that isn’t restful. This can lead to complications with cardiovascular and mental health, quality of life, and excessive sleepiness - which makes driving more dangerous. So how does breathing work, why does the airway get blocked with obstructive sleep apnea, and is there anything we can do about it?

Breathing is actually a pretty complex operation. Normally, breathing out is mostly an act of relaxing, but breathing in is a highly coordinated effort. Muscles in the diaphragm and chest contract to open the lungs and create a vacuum. The upper airway consists of the respiratory tract from the nose to above the vocal cords. This unique part of the body processes both food and air, requiring elasticity and flexibility to accomplish these competing tasks. It also produces speech sounds, chewing, sneezing, etc. The muscles that coordinate these tasks need to be contracted when breathing in for the airway to remain open. In OSA, the upper airway gets blocked.

When we lie down the fluid that pools in our legs flows up to the rest of the body, causing it to swell. When we sleep, the brain may not keep the throat muscles firm, causing a partial collapse of the throat. This is exacerbated when lying on the back, as the tongue and jaw fall into the airway. Alone, none of these would cause OSA. A partial blocking of the airway frequently results in snoring as bits of the throat flap in the breeze. OSA occurs when the changes we experience during sleep accompany structural damage to the upper airway. This damage can take many forms: a jaw that is small or set back in the throat, enlarged adenoid glands, and shifting bone structure. Additionally, increased adipose (fat) tissue in the neck can narrow the airway. Other risks include being male, obese, older, pregnant, and sleeping on the back. Some substances can increase the risk of OSA, including alcohol, cigarettes, sedatives, and hypnotics like benzodiazepines. These risk factors cause the throat to narrow or the brain to relax the jaw (or both) which causes the airway to temporarily collapse. Instead of pulling air into the lungs, the vacuum pulls the throat together. The body doesn’t get enough oxygen, and trouble increases from there.

So what can be done? A lot, actually! The first step is a diagnostic test. A nighttime in-laboratory sleep test called polysomnography is the go-to test, but home and portable sleep tests exist as well. Guidelines and directions must be carefully followed on portable kits to ensure accurate findings. If you do have OSA, the remedies vary widely. First, it’s a good idea to abstain from things that exacerbate OSA; like drinking and smoking. Second, sleeping on the side may provide some relief in mild cases. Beyond this, medical professionals may look into treating related disorders like asthma and heart failure. A sleep specialist may recommend or prescribe a Continuous Positive Airway Pressure (CPAP) machine, which pushes air into the throat instead of relying on the lungs to pull it in. These are highly effective but have low adherence, with around 50% of patients using the machines for less than 3 hours a night after the first month. In more severe cases, a specialist may recommend an oral appliance and/or surgery to physically change the structure of the airway. For many people, the solution to OSA may be to expand the airway by losing weight. This can be easier said than done, and clinical trials are looking into the effects of medications that induce weight loss for their ability to also tackle OSA. With luck, these new routes of treatment will let those with OSA breathe a little easier at night. 

Staff Writer / Editor Benton Lowey-Ball, BS, BFA

References

Choudhury, N., & Deshmukh, P. (2023). Obstructive Sleep Apnea in Adults and Ear, Nose, and Throat (ENT) Health: A Narrative Review. Cureus, 15(10). doi.org/10.7759/cureus.47637 

Del Negro, C. A., Funk, G. D., & Feldman, J. L. (2018). Breathing matters. Nature Reviews Neuroscience, 19(6), 351-367. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6636643/

Eckert, D. J., & Malhotra, A. (2008). Pathophysiology of adult obstructive sleep apnea. Proceedings of the American thoracic society, 5(2), 144-153. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2628457/

Otis, A. B., Fenn, W. O., & Rahn, H. (1950). Mechanics of breathing in man. Journal of applied physiology, 2(11), 592-607. Downloaded from journals.physiology.org/journal/jappl (073.035.112.088) on April 30, 2024

Sankri-Tarbichi, A. G. (2012). Obstructive sleep apnea-hypopnea syndrome: Etiology and diagnosis. Avicenna Journal of Medicine, 2(01), 3-8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3507069/