Latest Research: What Scientists Now Understand About Long COVID and the Heart (A 2024–2025 Science Update)
Updated for 2025 research
Long COVID has always been more than a lingering cough or stubborn fatigue. For many people, it feels like their body has changed in ways they can’t fully explain—especially their heart. Over the last two years, scientists have finally begun to uncover why. Researchers on three continents are now mapping the biological fingerprints that COVID-19 leaves behind in heart tissue, blood vessels, and the autonomic nervous system. Their findings don’t just validate patient experiences—they reveal entirely new pathways of cardiovascular injury that help explain why Long COVID symptoms can be so persistent.
Below is a science-based look at what researchers discovered in late 2024 and 2025, and how these findings support what many patients already know: something real is happening beneath the surface.
1. Persistent Heart Inflammation: A Hidden Footprint of the Virus
A major 2025 Mount Sinai study used advanced PET/MRI scans to detect ongoing myocardial and endothelial inflammation in people experiencing Long COVID symptoms. Unlike routine echocardiograms, these hybrid scans can detect:
immune cell activity inside the heart muscle
metabolic abnormalities in inflamed tissue
vascular wall thickening, a marker of endothelial stress
low-grade myocarditis that doesn’t appear on conventional testing
Why this matters:
Inflammation changes the heart’s efficiency at a cellular level, affecting how it contracts and uses oxygen. This could explain why patients report exercise intolerance even when their standard heart tests look normal.
2. Microclots and Vascular Injury: The “Small Vessel Disease” Theory Strengthens
Several landmark studies from 2024–2025 provide deeper evidence that Long COVID is fundamentally a vascular disease. Researchers found:
persistent microclots resistant to normal breakdown
abnormal fibrinogen and amyloid-like deposits in the bloodstream
reduced capillary perfusion in cardiac PET scans
signs of endothelial cell dysfunction, even months after infection
These microscopic blockages can reduce oxygen delivery in the smallest vessels supplying the heart, a process similar to early-stage coronary microvascular disease.
The key finding:
People with Long COVID may have impaired blood flow at the microvascular level—even without classic coronary artery blockages.
3. Autonomic Nervous System Disruption: How Long COVID Alters Heart Rate Control
Postural Orthostatic Tachycardia Syndrome (POTS) is widely recognized, but newer research shows the disruption is broader and more complex:
impaired baroreflex sensitivity (affecting blood pressure regulation)
altered parasympathetic/vagal tone, leading to poor heart-rate recovery
sympathetic overdrive, causing sudden spikes in heart rate
changes in circulating catecholamines, consistent with autonomic instability
These findings show that Long COVID doesn’t just inflame the heart—it alters how the nervous system controls the heart’s rhythm and blood pressure.
4. Mitochondrial Dysfunction: Why the Heart Feels “Out of Fuel”
Multiple studies point to changes in the heart’s mitochondria—the energy factories inside cells. Using spectroscopy and metabolic imaging, researchers found:
reduced mitochondrial ATP production
signs of oxidative stress
abnormal lactate buildup during light exertion
Because the heart is the most energy-demanding organ in the body, these findings offer a biological explanation for:
extreme fatigue
exercise intolerance
heart pounding with minimal activity
5. Emerging Biomarkers: Lab Clues for Long COVID Heart Involvement
New research is also identifying measurable biomarkers that could support diagnosis:
elevated IL-6, IL-1β, and TNF-alpha (inflammatory cytokines)
persistent D-dimer elevation in some cases
VEGF and sFlt-1 changes, linked to vascular remodeling
abnormal endothelial markers like VCAM-1 and ICAM-1
troponin and NT-proBNP elevations in a subset of patients
These markers are not specific enough to diagnose Long COVID on their own, but they offer a biological trail that helps clinicians understand what the body is experiencing.
6. Why These Findings Are Important for SSDI
The Social Security Administration (SSA) evaluates Long COVID heart symptoms under established cardiovascular listings, including Section 4.00: Cardiovascular System.
The newest research helps clarify:
why patients can have disabling symptoms despite normal routine tests
how microvascular dysfunction can limit exertion
why chronic inflammation affects daily functioning
why arrhythmias can be unpredictable and persistent
SSA focuses on how symptoms limit daily functioning, and these scientific insights help describe the mechanisms behind those limitations.
For the full cardiovascular overview of Long COVID and the heart, read our companion article:
Heart Issues and Long COVID: When the Virus Won’t Let Go of the Heart
COVID and Brain Fog
Scientists are discovering that Long COVID can affect not just the heart, but also how the brain processes information. “Brain fog” is more than forgetfulness — research shows measurable changes in brain activity, attention networks, and blood flow that can make it hard to concentrate, remember details, or stay mentally organized. These findings help explain why cognitive symptoms are so common and how they fit into the larger picture of Long COVID.
Hope for the Future - CLEARING UP THE COVID PICTURE
The science is finally catching up. A clearer picture of Long COVID’s impact on the heart is emerging—one rooted in measurable inflammation, vascular injury, autonomic disruption, and metabolic changes. As researchers continue to map these pathways, patients can expect:
more targeted treatments
better diagnostics
stronger recognition in medical and disability evaluations
improved long-term care
What once felt unexplained now has growing scientific grounding—and that brings hope.
You can learn more about Long COVID and other conditions in our article discussing “3 MAJOR DISABILITIES RELATED TO LONG COVID.”
References
Fleischer, N. L., Slocum, E., Patel, A., Xie, Y., McKane, P., Lyon-Callo, S., & Hirschtick, J. L. (2025). Long COVID and new onset disability nearly 2 years after initial infection. American Journal of Preventive Medicine, 68(6), 1168–1172.
https://www.sciencedirect.com/science/article/pii/S0749379725000765
Mount Sinai Reports. (2025, April 29). Persistent cardiovascular and pulmonary abnormalities found in individuals with Long COVID.
https://reports.mountsinai.org/article/card2026-long-covid
Jiang, X., et al. (2025). Long-term coronary microvascular and cardiac dysfunction after severe COVID-19 infection. JAMA Network Open, 8(6), e2118391.
https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2835113
CIDRAP. (2025, May 6). Long COVID patients show signs of inflammation on PET/MRI scans.
https://www.cidrap.umn.edu/covid-19/long-covid-patients-show-signs-inflammation-pet-mri-scans
Rashid, H., et al. (2025). Infection to hypertension: A review of post-COVID-19 new-onset hypertension. Frontiers in Cardiovascular Medicine, 12, 12399678.
https://pmc.ncbi.nlm.nih.gov/articles/PMC12399678
National Heart, Lung, and Blood Institute. (2024). COVID-19 increases risk of heart attack and stroke for three years after infection.
https://www.nhlbi.nih.gov/news/2024/first-wave-covid-19-increased-risk-heart-attack-stroke-three-years-later
Harvard Medical School. (2024). COVID’s damage lingers in the heart.
https://magazine.hms.harvard.edu/articles/covids-damage-lingers-heart
Social Security Administration. (2019). 4.00 Cardiovascular – Adult. Disability Evaluation Under Social Security (Blue Book).
https://www.ssa.gov/disability/professionals/bluebook/4.00-Cardiovascular-Adult.htm
Disclaimer
This article is for informational purposes only and does not constitute medical or legal advice. Consult with a qualified healthcare provider for medical questions. Consult with a licensed attorney for legal advice. This article does not create an attorney-client or doctor-patient relationship.
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