Jimeno-Almazán, Amaya, Pallarés, Jesús G, Buendía-Romero, Ángel et al. · Journal of clinical medicine · 2021 · DOI
Some people who recover from COVID-19 experience persistent fatigue and difficulty exercising for months afterward. This study tested 32 people with long-lasting COVID symptoms and found that about 12% had a specific heart problem called chronotropic incompetence—their heart rate doesn't increase normally during exercise. This heart rhythm problem may explain why some patients struggle with exercise intolerance after COVID-19.
This study identifies chronotropic incompetence as a potential cardiopulmonary mechanism underlying exercise intolerance in post-COVID syndrome. The findings are relevant to ME/CFS research because similar autonomic dysfunction and cardiac response abnormalities may contribute to post-exertional malaise and exercise intolerance in ME/CFS patients, suggesting shared physiological pathways warranting investigation.
This study does not establish chronotropic incompetence as the primary cause of post-COVID fatigue or demonstrate that this finding is specific to COVID-19 rather than other conditions. The small sample size and cross-sectional design preclude causal inference or determination of how common this abnormality truly is in the broader post-COVID population. Results cannot be generalized to hospitalized or more severely affected COVID-19 patients.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Jimeno-Almazán, Amaya, Pallarés, Jesús G, Buendía-Romero, Ángel, Martínez-Cava, Alejandro, & Courel-Ibáñez, Javier (2021). Chronotropic Incompetence in Non-Hospitalized Patients with Post-COVID-19 Syndrome.. Journal of clinical medicine. https://doi.org/10.3390/jcm10225434
BibTeX
@article{mecfsatlas-jimeno-almazn-2021-chronotropic-incompetence,
author = {Jimeno-Almazán, Amaya and Pallarés, Jesús G and Buendía-Romero, Ángel and Martínez-Cava, Alejandro and Courel-Ibáñez, Javier},
title = {Chronotropic Incompetence in Non-Hospitalized Patients with Post-COVID-19 Syndrome.},
journal = {Journal of clinical medicine},
year = {2021},
doi = {10.3390/jcm10225434},
note = {PubMed: 34830716},
url = {https://www.mecfsatlas.com/evidence/jimeno-almazn-2021-chronotropic-incompetence},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-26. https://www.mecfsatlas.com/evidence/jimeno-almazn-2021-chronotropic-incompetence
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