Long Covid Newsletter
Issue #36May 11, 20267 studies

Long COVID linked to 2x higher heart disease risk in Stockholm study of 9,000 patients

This week brought major advances in understanding long COVID's biological mechanisms and health impacts. From brain changes in mice to cardiovascular risks in humans, researchers are mapping how the virus leaves lasting marks on multiple body systems.

🫀 Long COVID Doubles Heart Disease Risk

  • 8,999 people with physician-diagnosed long COVID in Stockholm showed dramatically higher rates of cardiovascular events compared to 1.2 million controls

  • Women with long COVID had 18.2% cumulative incidence of heart problems vs 8.4% in controls; men showed 20.6% vs 11.1%

  • Cardiac arrhythmias were the biggest concern—long COVID increased risk by 3x in women and 61% in men, even after adjusting for other health factors

Why it matters: This is the first large population study showing long COVID significantly raises heart disease risk in community patients (not just hospitalized cases), suggesting millions may need cardiovascular monitoring.

🥈 Top 2% journal 🔗 EClinicalMedicine Journal Article 🗓️ May 4

Key Findings

🧠 Virus Damages Brain's Sleep-Wake System in Mice

  • SARS-CoV-2 caused lasting loss of brain neurons and suppressed orexin—a key chemical that regulates sleep, appetite, and alertness—in infected mice

  • Viral RNA persisted in mouse brains well beyond acute infection, coinciding with focal loss of cortical neurons

  • Supplementing orexin-A/B increased neuron survival both in lab dishes and living mice under tested conditions

💡 May help explain why long COVID patients struggle with fatigue, sleep problems, and brain fog.
🥉 Top 5% journal 🔗 Journal of neuroinflammation Journal Article 🗓️ May 5

🔬 Children's Immune Systems Reveal Long COVID Subgroups

  • 74 children with severe long COVID showed distinct immune and metabolic patterns that changed over time—SARS-CoV-2 markers declined within 1 year while inflammatory signals persisted

  • Higher hemoglobin levels linked to worse function in kids who'd never had Epstein-Barr virus, while higher IL-12p40 and thiamine levels tracked with milder symptoms

  • Blood protein NfL (neurofilament light chain) inversely correlated with functional status, suggesting ongoing nerve damage

💡 Could lead to blood tests that help doctors identify which children need more intensive long COVID treatment.
🥈 Top 2% journal 🔗 Nature communications Journal Article 🗓️ May 4

🩸 Blood Vessel Problems Drive Heart Symptoms

  • 19 long COVID patients with heart symptoms had severely disrupted blood vessel function—lower nitric oxide and higher ADMA (a compound that impairs blood vessels)

  • These patients showed 3-fold higher inflammatory markers and significantly worse heart pumping ability compared to 20 recovered patients and 10 never-infected controls

  • Blood vessel dysfunction correlated with worse heart strain measurements and elevated heart damage markers

💡 Suggests long COVID heart problems stem from blood vessel inflammation rather than direct heart muscle damage.
Top 20% journal 🔗 Frontiers in cardiovascular medicine Journal Article 🗓️ May 7

🎵 Singing Lessons Help Long COVID Breathing

  • 1,413 long COVID patients completed a 6-week online breathing program using singing techniques, with 84% providing follow-up data

  • Participants reported median 415 days of long COVID symptoms before starting the program

  • Breathing scores improved significantly: walking breathlessness dropped by 5 points, stair climbing by 10 points on visual scales, plus better quality of life measures

💡 Shows accessible, low-cost interventions may help the millions struggling with long COVID breathlessness.
🥇 Top 1% journal 🔗 The Lancet. Digital health Journal Article 🗓️ May 8

📊 Machine Learning Spots Long COVID Risk Factors

  • AI analysis of 17,200 people in the NIH All of Us program found that combining medical records with survey and genetic data improved long COVID prediction accuracy from 73.6% to 74.8%

  • Active military service and self-reported fatigue emerged as top predictive factors beyond standard medical data

  • The improvement was modest, raising questions about whether the cost of collecting extra data is worth the small gain in accuracy

💡 Suggests long COVID risk is complex and may require multiple types of data to predict reliably.
🥉 Top 5% journal 🔗 Communications medicine Journal Article 🗓️ May 5

🔄 Comprehensive Rehab Shows Lasting Benefits

  • 75 long COVID patients completed a 6-week program with aerobic training, breathing exercises, and strength training, with improvements maintained at 6-month follow-up

  • Patients with lower baseline capacity showed the greatest functional gains, while benefits were consistent across age and sex groups

  • The study was the first to analyze voice and speech problems in long COVID alongside standard rehabilitation measures

💡 Multi-component rehabilitation may provide sustained benefits, especially for those most severely affected.
Top 20% journal 🔗 Scientific reports Journal Article 🗓️ May 5

Implications

These studies reveal long COVID as a complex, multi-system condition affecting the brain's sleep centers, blood vessels, and immune system in measurable ways. The cardiovascular findings are particularly concerning given the millions affected, while the rehabilitation and breathing intervention results offer hope for evidence-based treatments.

Studies in this issue

Primary sources used for this newsletter.

  1. Long COVID and the risk of developing new heart and blood vessel diseases
    main storyEClinicalMedicine2026-05-04PMID 42077647
  2. Using data from different sources improves machine learning to identify long COVID
    key findingCommunications medicine2026-05-05PMID 42086912
  3. COVID-19 infection is linked to reduced brain wakefulness signals and lasting loss of nerve cell markers in thinking areas
    key findingJournal of neuroinflammation2026-05-05PMID 42087199
  4. Comprehensive rehabilitation may help improve function and reduce symptoms in long COVID over six months
    key findingScientific reports2026-05-05PMID 42086796
  5. Online Singing Breathing Program and Wellbeing in People with Long COVID Breathlessness in the UK
    key findingThe Lancet. Digital health2026-05-08PMID 42103518
  6. Patterns of immune and metabolism changes identify groups in children with long COVID
    key findingNature communications2026-05-04PMID 42082458
  7. Blood vessel and heart problems in long COVID with heart symptoms linked to imbalance in a key blood vessel signaling pathway
    key findingFrontiers in cardiovascular medicine2026-05-07PMID 42095154

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