Many people with post-COVID experience persistent fatigue. For some of them, heart measurements show abnormalities. For a long time, it was believed that these changes were mainly the result of fitness loss due to lack of movement. This is referred to as cardiac deconditioning.
A new publication in the British Journal of Sports Medicine explains that this explanation is not always sufficient. NMCB researchers Rob Wüst and Braeden Charlton contributed to this publication.
For example, during exercise tests, it is observed that the heart does not fill with blood properly. There are also indications of inflammation in the heart. In addition, studies point to issues in the energy balance of cells and disturbances in the small blood vessels. This may help explain why exercise leads to persistent heart and exertion-related complaints in some patients.
The findings are important for healthcare. Heart abnormalities in post-COVID should be carefully assessed. Deconditioning may play a role, but it does not explain all the findings. Therefore, a standard progression of exercise is not necessarily suitable for every patient. Treatment should be tailored to what the individual can handle to prevent worsening symptoms.
Read a Dutch-language explanation of this review on the NMCB website:
👉 Cardiac Changes in Post-COVID Beyond Deconditioning
Read the full scientific review here:
👉 https://bjsm.bmj.com/content/early/2026/02/09/bjsports-2025-111387.long