Understanding the causes of breathlessness in people with long-COVID

People with long-COVID continue to have health problems for many months or years after infection. It’s a big health and economic problem in the UK, affecting nearly 2 million people and costing £8 billion each year. 

Many people with long-COVID experience breathing difficulties. They have a pattern of erratic breathing at rest and during exercise, despite their lung function being normal. We don’t know why this happens, but evidence suggests it’s caused by disruption of the control of breathing, coordinated by the brain and nervous system, rather than a specific lung problem.  

A key part of this breathing control system is the carotid chemoreflex. This is driven by small organs in the neck called the carotid bodies, which monitor the chemical status of the blood, sending signals into the brain causing breathing and circulatory adjustments. The carotid chemoreflex controls breathing and feelings of breathlessness.  

When someone is infected with COVID-19, the virus enters the carotid bodies and disrupts their normal function. This may explain why some patients with long-COVID are breathless at rest and during exercise. Our recent research shows that the carotid chemoreflex is more sensitive in people with long-COVID, without other health problems.  

Project aims

We want to find out whether temporarily inactivating the carotid bodies improves breathing at rest and during exercise in people with long-COVID. We will monitor whether this reduces hyperventilation at rest and improves breathing efficiency during exercise.  

What we hope to achieve

At the moment there aren’t any evidence-based treatments for people with long-COVID. Our study will shed light on whether the carotid body could be a target for future treatment for patients with long-COVID with unexplained breathing difficulties. We hope it will lead to a larger study on whether inactivating the carotid bodies helps manage these patients’ breathlessness.