Post-COVID-19 Sleepiness Could be Undiagnosed Obstructive Sleep Apnea, Study Finds

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A new study found a 35% prevalence of newly diagnosed obstructive sleep apnea in patients with lingering COVID-19 symptoms of fatigue or sleepiness.

Post-COVID-19 symptoms like daytime sleepiness, fatigue, and memory/concentration problems may be because of reduced sleep efficiency and undiagnosed obstructive sleep apnea, a new study found.1

People who have COVID-19 have reported experiencing symptoms, such as chronic pain, brain fog, shortness of breath, chest pain, and intense fatigue, for either weeks, months, or years after a SARS-Cov-2 infection. One 2021 study found 76% of 1655 patients with COVID-19 had persistent symptoms for 6 months after leaving the hospital. Symptoms included respiratory and cardiac symptoms, as well as neurological symptoms—63% had fatigue, 26% had sleep difficulties, 11% had smell disorders, 7% had taste disorders, 6% had dizziness, and 2% had myalgia and headache.

A U.S. Household Pulse Survey, conducted by the Census Bureau and National Center for Health Statistics, found the percentage of participants with lingering or new symptoms post-COVID dropped to 11% in January 2023 from 19% in June 2022. The decline reason remains unknown. A Yale Medicine cardiologist, Erica Spatz, MD, MHS, believed the decline could be due to more people getting vaccinated, as well as milder variants.2

A new single-center retrospective study, led by Katja Menzler, from the department of Neurology at Philipps-University Marburg in Marburg, Germany, aimed to evaluate the polysomnographic results of post-COVID-19 patients—and thus diagnosing potential sleep disorders. The study referred to the condition of experiencing lingering COVID-19 symptoms for > 12 weeks as “post-COVID syndrome.” Though, the Centers for Disease Control (CDC) refers to experiencing symptoms for > 4 weeks as “Post-COVID Conditions.”3 Risk factors linked to post-COVID syndrome include female, sex, middle age, other chronic diseases or psychiatric diseases, and the severity of the infection.

The study included 34 patients with post-COVID syndrome between March 2021 and December 2022. The sample had a mean age of 45.5 ± 12.1 years, as well as 27 females and 7 males. All patients reported new-onset fatigue and sleepiness after SARS-CoV2 infection. Patients underwent polysomnography between January 2021 and October 2022.

After getting infected by COVID-19, one patient had excessive snoring and witnessed apnea;, another patient had preexisting snoring without apnes (after the infection snoring had increased), 4 patients had occasional snoring, 3 patients had previous asthma, and one patient had a history of pulmonary.

The polysomnography revealed 26% (n = 9) had a sleep latency of < 30 minutes, 35% (n = 12) had a total sleep time of < 6 hours, and 50% (n = 17) had a reduced sleep efficiency of < 80%. None of the patients demonstrated sleep-onset rapid eye movement (REM). The findings revealed a 35% prevalence of newly diagnosed obstructive sleep apnea in patients with fatigue stemmed from their COVID-19 infection.

“Reports of the prevalence of [obstructed sleep apnea] in the general population vary, but range between 9% and 38% for mild to severe cases, and between 6% and 17% for only moderate to severe cases,” the investigators wrote. “The percentage of all [obstructed sleep apnea] cases observed in the present study was therefore in the upper range, and the percentage of moderate to severe cases was slightly higher than reports in the general population.”

The investigators concluded by stating the treatment of obstructive sleep apnea with CPAP improved daytime sleepiness.

“An improvement in fatigue was reported in these two patients after initiation of automatic positive airway pressure therapy,” the investigators wrote. “In line with these results, CPAP treatment led to discontinuation of daytime symptoms in the 50% of patients with [obstructive sleep apnea] who agreed to and tolerated CPAP treatment in our study, supporting our suggestion of [obstructed sleep apnea] being a treatable cause of fatigue and daytime sleepiness in patients with post-COVID syndrome.”


  1. Menzler K, Mayr P, Knake S, et al. Undiagnosed obstructive sleep apnea syndrome as a treatable cause of new-onset sleepiness in some post-COVID patients [published online ahead of print, 2023 Nov 21]. Eur J Neurol. 2023;10.1111/ene.16159. doi:10.1111/ene.16159
  2. Katella, K. What Happens When You Still Have Long COVID Symptoms? Yale Medicine. October 27, 2023.,intense%20fatigue%2C%20can%20be%20debilitating. Accessed November 22, 2023.
  3. Post-COVID Conditions: Information for Healthcare Providers. Centers for Disease Control and Prevention. September 11, 2023. Accessed November 22, 2023.