Long COVID Linked to Elevated Heart Disease Risk, Major Swedish Study Finds

STOCKHOLM — Adults diagnosed with long COVID face a significantly higher risk of developing serious cardiovascular conditions, including heart arrhythmias and coronary artery disease, according to a massive prospective study from the Karolinska Institutet. The research, published April 2, 2026, in eClinicalMedicine, suggests that even those who experienced mild initial infections—never requiring hospitalization—may remain vulnerable to heart-related complications for years following their recovery.

By following more than 1.2 million adults over a four-year period, researchers identified a sobering trend: cardiovascular events were nearly twice as common in women with long COVID compared to those without the condition. While the increased risk was also present in men, the study highlights a particular need for clinical vigilance regarding “invisible” symptoms in women.

Unmasking the Cardiovascular Toll

The research team, led by Pia Lindberg of the Karolinska Institutet, analyzed a Swedish cohort of adults aged 18 to 65. Within this group, approximately 9,000 individuals (0.7%) were formally diagnosed with long COVID, also known as post-COVID condition (PCC).

The statistical breakdown reveals a clear divergence in health outcomes over the follow-up period:

• Women with long COVID: 18.2% experienced a cardiovascular event, compared to 8.4% of those without the condition.

• Men with long COVID: 20.6% experienced an event, compared to 11.1% of those without.

Even after researchers adjusted for age, socioeconomic status, and pre-existing health habits, the associations remained “robust.” Women with long COVID were found to have just over twice the risk of receiving a new cardiovascular diagnosis. Men faced a risk approximately one-third higher than their peers who did not develop long-term symptoms.

Specific Conditions Identified

The study did not just find general “heart issues” but pointed toward specific clinical diagnoses. Both men and women showed elevated rates of:

• Cardiac Arrhythmias: Abnormal heart rhythms, such as atrial fibrillation.

• Coronary Artery Disease: Damage or disease in the heart’s major blood vessels.

Notably, women in the long COVID group also showed an increased risk of heart failure and peripheral vascular disease (reduced blood flow to the limbs), suggesting that the inflammatory impact of the virus may manifest differently across genders.

Beyond the Hospital Walls

One of the most significant aspects of this study is its focus on “non-hospitalized” patients. Early in the pandemic, it was widely assumed that only those with severe respiratory failure or ICU stays were at risk for long-term organ damage.

“Our findings suggest that long COVID can be a risk factor for cardiovascular disease even in younger people who were previously healthy and did not require hospital care during their acute infection,” stated lead author Pia Lindberg in a press release.

This aligns with a growing body of global evidence. A landmark 2022 study in Nature Medicine first sounded the alarm, reporting increased risks of inflammatory heart disease and thromboembolic (blood clotting) disorders post-infection. Furthermore, a 2025 meta-analysis involving 10 million people confirmed that these risks are not isolated incidents but a global public health trend.

Why the Heart? The Science of Persistence

Researchers are still working to pin down exactly why a respiratory virus triggers long-term heart issues. Current theories focus on several “biological holdovers” from the initial infection:

1. Chronic Inflammation: The immune system may remain in a “high alert” state, damaging the lining of the blood vessels (endothelium).

2. Autonomic Dysfunction: The virus may disrupt the nervous system’s ability to regulate heart rate and blood pressure.

3. Microclots: Tiny, persistent blood clots may impair oxygen delivery to tissues, stressing the heart muscle over time.

Expert Perspectives: A Call for Structured Follow-Up

Medical professionals not involved in the study emphasize that the findings should change how we view “lingering” symptoms.

“This is a wake-up call for both patients and providers,” says Dr. Elena Rossi, a cardiologist specializing in post-viral syndromes (not affiliated with the Karolinska study). “Symptoms like palpitations, shortness of breath, or extreme fatigue are often dismissed as ‘just part of the recovery.’ We now see that these may be the early warning signs of underlying vascular changes.”

Lindberg notes that structured follow-up is particularly vital for women, whose cardiovascular symptoms are frequently atypical—presenting as fatigue or nausea rather than the “classic” crushing chest pain often seen in men.

Practical Advice: What This Means for You

While the data may seem alarming, experts stress that a long COVID diagnosis is not a guarantee of heart disease. Instead, it should be viewed as a modifiable risk factor, similar to high blood pressure or high cholesterol.

For Patients

If you have had COVID-19 and continue to experience the following, consult a healthcare professional:

• Palpitations: A feeling that your heart is skipping a beat, fluttering, or beating too hard.

• Chest Discomfort: Any pressure, tightness, or pain during physical activity or rest.

• Exercise Intolerance: Feeling unusually winded after minor exertion, like climbing a flight of stairs.

• Swelling: Unexplained swelling in the legs, ankles, or feet.

For Clinicians

The study suggests a lower threshold for cardiovascular screening in post-COVID patients. Standard check-ups should prioritize monitoring blood pressure, lipid profiles, and heart rhythms to catch potential issues before they escalate into major events like heart attacks or strokes.

Limitations and Nuance

As with any observational study, there are caveats. Because this research relied on formal medical codes for “Long COVID,” it likely captures only the most symptomatic 0.7% of the population. This means the true number of people affected could be higher, or the risk profile could look different for those with very mild lingering symptoms who never sought a diagnosis.

Furthermore, while the study shows a strong association, it does not definitively prove that COVID-19 caused every heart event. Other factors, such as changes in lifestyle or delayed routine care during the pandemic, could play a role.

The Bottom Line

The Karolinska Institutet study reinforces a shift in the medical community’s understanding of COVID-19: it is a multi-systemic disease with potential long-term “echoes” in the cardiovascular system. By recognizing long COVID as a legitimate risk factor for heart disease, public health systems can better prepare for the long-term needs of a post-pandemic population.

References

• Karolinska Institutet News Release: Long COVID associated with increased risk of cardiovascular disease. April 1, 2026.

Medical Disclaimer: This article is for informational purposes only and should not be considered medical advice. Always consult with qualified healthcare professionals before making any health-related decisions or changes to your treatment plan. The information presented here is based on current research and expert opinions, which may evolve as new evidence emerges.