COVID-19 infection is linked to a measurably higher risk of developing obstructive sleep apnea, according to multiple large studies tracking patients for months to years after their initial illness. The increased risk appears in both hospitalized and non-hospitalized patients, and the relationship is complicated by the fact that the virus and sleep apnea seem to worsen each other. Untangling the direct effects of the virus from pandemic-era lifestyle changes and diagnostic shifts makes the picture messier than a simple cause-and-effect story, but the signal in the data is consistent enough that researchers and sleep clinicians are paying close attention.
How Much Higher Is the Risk After Infection
Two large population-level studies provide the clearest numbers. One, using data from an urban population followed for up to four and a half years, found that hospitalized COVID patients had roughly a 40 percent higher risk of being diagnosed with new obstructive sleep apnea compared to people who never tested positive, while non-hospitalized COVID patients had about a 33 percent higher risk.1Scientific Reports. Risk of new-onset obstructive sleep apnea up to 4.5 years after COVID-19 in the urban population A separate study looking at a larger cohort found an even stronger association, with COVID patients about 50 percent more likely to receive an obstructive sleep apnea diagnosis at three months and nearly 60 percent more likely at one year, compared to matched individuals without a COVID history.2PubMed. The prevalence of obstructive sleep apnea syndrome after COVID-19 infection
These are not small, obscure signals. Both studies used statistical adjustments to account for factors like age, obesity, and other health conditions, and the association held. The persistence of the risk over years rather than weeks argues against this being just a temporary inflammatory response. Whether the virus truly causes sleep apnea or triggers something that was already lurking beneath the surface in many of these patients is a harder question, and one the data alone cannot fully resolve.
Post-COVID Fatigue That Turns Out to Be Sleep Apnea
One of the more striking findings comes from sleep clinics evaluating patients who showed up complaining of persistent fatigue or excessive daytime sleepiness after their COVID infection. When researchers put these patients through formal sleep studies, about 35 percent turned out to have obstructive sleep apnea that had never been diagnosed before.3European Journal of Neurology. Post-COVID-19 Sleepiness Could be Undiagnosed Obstructive Sleep Apnea, Study Finds Among those newly diagnosed, the severity ranged from mild to severe, with close to a quarter of the group having moderate or severe cases.4PubMed Central. Undiagnosed obstructive sleep apnea syndrome as a treatable cause of new‐onset sleepiness in some post‐COVID patients
This raises an uncomfortable possibility. Many people walking around with long-COVID fatigue might actually have a treatable sleep disorder that just happened to become noticeable after their infection. Whether COVID unmasked something that was already developing, or whether the virus tipped these patients over a threshold, the practical message is the same: if you recovered from COVID months ago but still feel chronically exhausted or unrested despite getting enough sleep, it is worth getting screened for sleep apnea rather than simply attributing everything to long COVID.
A long-COVID clinic in northeast Ohio that systematically referred patients for home sleep testing found that roughly 16 percent of those tested had moderate-to-severe sleep apnea with an index above 15 events per hour, while about 41 percent had normal results below 5 events per hour.5SLEEP. 1408 Assessments of Sleep and Home Sleep Testing Referrals from a Long COVID Clinic in Northeast Ohio That still leaves a meaningful chunk in the middle, people with mild sleep-disordered breathing that might never have been noticed without post-COVID symptoms pushing them toward a sleep evaluation.
What the Virus Might Be Doing to Breathing During Sleep
The mechanism by which COVID could promote sleep apnea is not neatly established, and the research so far paints a surprisingly mixed picture. A study that directly measured the key physiological traits underlying sleep apnea found no meaningful differences between people with a COVID history and those without when it came to the big three culprits: upper airway collapsibility, the sensitivity of the brain’s breathing control loop, and the arousal threshold that determines how easily you wake up from a breathing event.6PubMed Central. Sleep Apnea Pathophysiology in Patients with a History of COVID-19 The one difference that did emerge was a higher ventilatory response to arousal, meaning that when people with a COVID history woke briefly during sleep, their breathing overcompensated more than normal. That kind of overshoot can destabilize the cycle of breathing and arousal in ways that sustain apnea events, but it is a subtle finding rather than a dramatic smoking gun.
There are other plausible pathways researchers are exploring, even if direct evidence is still thin. COVID is known to cause inflammation throughout the body, including in the upper airways. Persistent swelling or tissue changes in the throat and nasal passages could narrow the airway just enough to matter during sleep, when muscle tone naturally decreases. The virus can also affect the nervous system in ways that disrupt the brain’s control of breathing muscles, and case reports have documented diaphragm weakness following COVID infections. One published case described a patient with bilateral diaphragmatic impairment confirmed on testing months after COVID, leading to ongoing breathing difficulty despite the original lung infection having cleared.7PubMed Central. A Bilateral Diaphragmatic Paralysis Post-COVID-19 Infection: A Case Report and a Review of the Literature Damage to the diaphragm or the nerves controlling it could contribute to breathing instability during sleep, even if the lungs themselves have recovered.
The pattern is not unique to SARS-CoV-2. Sleep-disordered breathing and central apnea have been observed after other viral respiratory epidemics, including the original SARS outbreak and influenza. Respiratory viruses are known to invade or damage the parts of the brain that control breathing rhythm, which can show up as sleep-disordered breathing during or after the acute illness.8PubMed Central. Pediatric sleep apnea and viral respiratory infections: what do clinicians need to know? COVID may be doing something similar, potentially on a larger scale given how many people were infected.
Sleep Apnea Also Makes COVID Worse
The relationship between COVID and sleep apnea runs in both directions. People who already had obstructive sleep apnea before catching COVID faced roughly double the risk of a severe outcome, even after accounting for obesity, age, sex, and other health conditions that tend to cluster with sleep apnea.9PubMed Central. Obstructive sleep apnea is an independent risk factor for severe COVID-19: a population-based study The fact that this association survived adjustment for obesity is important because skeptics might argue that the real risk factor is being overweight, with sleep apnea just along for the ride. But the data suggest sleep apnea carries its own independent risk.
There is a nuance here, though. A separate study found that the severity of sleep apnea mattered, not just its presence. Having a diagnosis of obstructive sleep apnea was not, by itself, a statistically significant risk factor for worse COVID outcomes in that particular analysis, but having a more severe degree of the condition was.10Sleep Medicine Research. Is Obstructive Sleep Apnea a Risk Factor for Severe COVID-19? This makes physiological sense. Mild sleep apnea may not disrupt blood oxygen levels and systemic inflammation enough to meaningfully interact with a viral lung infection, but moderate or severe cases, with dozens of breathing interruptions per hour, push the body into a state of chronic stress that could impair the immune response and worsen outcomes.
This bidirectional relationship creates a vicious cycle for some patients. They contract COVID, which worsens or triggers sleep apnea, which in turn leaves them with the kind of fragmented sleep and low-grade oxygen deprivation that slows recovery and amplifies lingering symptoms. It also means that diagnosing and treating sleep apnea after a COVID infection is not just about sleep quality. It may have real implications for how fully someone recovers from the infection itself.
How Much of This Is the Pandemic Rather Than the Virus
You cannot talk about new sleep apnea diagnoses during and after the pandemic without confronting a major confounding factor: the pandemic changed how people lived, ate, exercised, and slept in ways that are themselves risk factors for developing sleep apnea. A study of existing sleep apnea patients found that those experiencing high stress during the pandemic were far more likely to gain weight, with nearly two-thirds of the most anxious patients putting on pounds, and over 80 percent reporting changes to their sleep schedule.11PubMed Central. The Management of Obstructive Sleep Apnea Patients during the COVID-19 Pandemic as a Public Health Problem-Interactions with Sleep Efficacy and Mental Health Weight gain is the single strongest modifiable risk factor for obstructive sleep apnea, and pandemic-era disruptions to routines, exercise, and mental health drove weight gain across the population.
So when studies find more sleep apnea diagnoses in people who had COVID compared to those who did not, some of that difference may reflect the broader lifestyle upheaval rather than a direct viral effect. The large cohort studies try to adjust for body mass and other measurable confounders, and the association still holds, but no statistical adjustment can perfectly separate “your body changed because of the virus” from “your body changed because you spent two years stuck at home, stressed, and eating more.” The researchers behind these studies are generally candid about this limitation.
There is also a detection-bias argument. People who had COVID, especially those with lingering symptoms, interacted with the medical system far more often afterward. If you are seeing doctors regularly for post-COVID fatigue, you are more likely to end up in a sleep lab than someone who never had a reason to complain about tiredness. Some of those 35 percent of long-COVID patients newly diagnosed with sleep apnea may have developed it years before their COVID infection but never had a reason to get tested. COVID did not cause their apnea, it caused their testing.
Getting Tested and Treated After COVID
If you have persistent fatigue, daytime sleepiness, or unrefreshing sleep months after a COVID infection, sleep apnea screening makes practical sense regardless of the ongoing debate about causation. Home sleep testing has become more accessible and is the standard first step for most adults without complex medical histories. The results are straightforward: if you are averaging more than five breathing disruptions per hour, you likely have some degree of sleep apnea, and if you are above 15 events per hour, treatment with positive airway pressure therapy is standard.
For people who already had sleep apnea and used a CPAP machine before the pandemic, the good news is that research found the pandemic did not significantly disrupt CPAP effectiveness or adherence overall.12PubMed Central. Telemetric Assessment of Continuous Positive Airways Pressure (CPAP) Effectiveness and Adherence in Obstructive Sleep Apnea during COVID-19 Pandemic However, certain subgroups, including older patients and those with diabetes or high blood pressure, did show some pandemic-related changes in how well their CPAP therapy was working. If you fall into those categories and felt like your CPAP was less effective during or after the pandemic, it may be worth getting your settings reassessed rather than assuming nothing has changed.
The treatment itself has not changed because of COVID. Positive airway pressure remains the first line for moderate-to-severe obstructive sleep apnea. Oral appliances, weight management, positional therapy, and in some cases surgery are options depending on severity and the anatomy involved. What has changed is awareness. Clinicians working in long-COVID clinics are increasingly incorporating sleep assessments into their standard evaluations, recognizing that a subset of patients carrying a long-COVID label may have a condition with a well-established treatment pathway.
When Sleep Apnea Was Already There
The 35 percent prevalence figure from post-COVID sleep studies needs context. Obstructive sleep apnea is strikingly common in the general population, particularly among middle-aged and older adults who carry extra weight. Estimates of undiagnosed sleep apnea in the broader population range widely but consistently suggest that a large proportion of people who have it do not know. The patients in the post-COVID studies who were newly diagnosed tended to be older and had a trend toward higher body weight compared to those who tested normal.4PubMed Central. Undiagnosed obstructive sleep apnea syndrome as a treatable cause of new‐onset sleepiness in some post‐COVID patients Those are the same risk factors that predict sleep apnea in any population, COVID or not.
This does not invalidate the association, but it does mean the situation is more nuanced than “COVID gives you sleep apnea.” For many people, the virus may have been the straw that broke the camel’s back, pushing a borderline airway over the threshold, or it may have simply been the catalyst that finally got someone into a sleep lab. Either way, the outcome is the same for the individual: a diagnosis that explains their symptoms and opens the door to treatment. Whether COVID caused it, worsened it, or merely revealed it matters for researchers trying to understand the virus’s long-term effects, but it matters less for the person who can now get a CPAP and start sleeping better.
What Remains Genuinely Unknown
The honest answer is that the evidence is stronger for an association than for a clear mechanism. The large cohort studies consistently show more sleep apnea diagnoses after COVID, and the risk increases hold up after statistical adjustments, but the physiological study that directly measured the traits that cause sleep apnea found almost no differences between COVID and non-COVID groups.6PubMed Central. Sleep Apnea Pathophysiology in Patients with a History of COVID-19 That is a real tension in the literature. If COVID were directly damaging the upper airway or fundamentally changing how the brain controls breathing during sleep, you would expect to see it in those measurements. The fact that researchers mostly did not suggests either the mechanism is subtler than expected, the effect operates through pathways not yet tested, or a significant chunk of the observed association comes from confounding and detection bias.
Longer-term follow-up will help. One of the key studies tracked patients for up to four and a half years, and the risk remained elevated throughout that window.1Scientific Reports. Risk of new-onset obstructive sleep apnea up to 4.5 years after COVID-19 in the urban population If the elevated risk persists at the seven- or ten-year mark, the case for a durable biological effect strengthens. If it flattens out as pandemic-era weight gain and lifestyle disruptions normalize, that points more toward environmental confounders. The research community is still collecting data, and the definitive answers are probably years away.
In the meantime, the practical takeaway is straightforward. COVID infection is associated with a higher chance of developing sleep apnea, the overlap in symptoms means many cases go unrecognized, and the condition is highly treatable once diagnosed. If post-COVID fatigue is dragging on, a sleep study is one of the most productive tests you can ask for.