People who suffer from long COVID tend to feel breathless - and now a study might have uncovered the reason why.
Researchers believe that disturbed sleep may be behind the breathlessness that long COVID patients often experience.
It is thought this could be associated with other common post-COVID symptoms such as anxiety and muscle weakness.
The study of patients in 38 institutions across the UK was published in The Lancet Respiratory Medicine.
Doctors discovered that 62% of participants who had been admitted to hospital for coronavirus had sleep disruption, which was likely to persist for at least 12 months.
On average, participants who had been hospitalised with COVID-19 slept for over an hour longer, but their sleep patterns were less regular – with a 19% decrease on the sleep regularity scale – than other hospital patients.
The researchers believe that anxiety, reduced muscle function and breathlessness could all be associated with sleep disruption, and that patients might be able to be helped by treatments to alleviate reduced muscle function and anxiety.
The study used extensive data from patients hospitalised with COVID between March 2020 and October 2021.
Sleep quality was self-reported by 638 patients and measured in another 729 patients, who wore devices similar to smart watches that measured night-time activity levels.
Both measures consistently revealed a higher prevalence of sleep disturbance in people who had been hospitalised with coronavirus.
Lead author Dr John Blaikley, a clinical scientist from University of Manchester and respiratory doctor, said: "This study has discovered that sleep disturbance could be an important driver of post-COVID-19 breathlessness – or dyspnea – because of its associations with reduced muscle function and anxiety.
"If this is the case, then interventions targeting poor sleep quality might be used to manage symptoms and convalescence following COVID-19 hospitalisation, potentially improving patient outcomes."
Researcher Callum Jackson, from University of Manchester, said: "Understanding the causes of breathlessness is complex since it can arise from conditions that affect the respiratory, neurological, cardiovascular, and mental health systems.
"These same systems are also affected by sleep disturbance, another symptom that has been frequently reported after COVID-19.
"Our findings suggest that sleep disturbance is a common problem after hospitalisation for COVID-19 and is associated with breathlessness.
"We also show this is likely to persist for at least 12 months as subjective sleep quality did not change between five and 12-month follow-up visits."
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