Strenuous Exercise tied to Temporary Inflammation in Stable CAD, suggests study

A new study published in the Journal of American Heart Association showed that in patients with stable coronary artery disease (CAD), acute vigorous exercise causes short-term elevations in inflammatory markers that diminish within two hours.

CAD is the most prevalent form of cardiovascular disease, which continues to be the leading cause of mortality worldwide. Acute myocardial infarction is caused by atherosclerosis-driven plaque growth and rupture, and each step of the disease's evolution is largely dependent on persistent low-grade inflammation. Endothelial dysfunction, lipid accumulation, foam cell production, and fibrous cap weakening are all facilitated by inflammatory pathways.

Cholesterol-lowering treatments diminish risk, but residual inflammatory risk remains, as seen in CANTOS, where interleukin-1β inhibition decreased recurrent occurrences regardless of cholesterol levels. Exercise controls inflammation. While regular training may have anti-inflammatory effects, the data is still conflicting. Acute, intense exertion temporarily raises proinflammatory markers. In order to compare the acute and 12-week inflammatory responses to high-intensity interval training against usual therapy, researchers carried out a randomized controlled experiment in 168 individuals with stable CAD.

Blood samples were taken prior to, during, and two hours following a maximum incremental cycling test in 168 individuals with stable CAD. After that, 142 participants finished follow-ups after being randomly assigned to either normal care or 12 weeks of high-intensity interval training. At baseline, week six, and week twelve, measurements were taken of high-sensitivity CRP (C-reactive protein), leukocytes, interleukin-2, interleukin-6, interleukin-10, interferon-γ, and tumor necrosis factor-α.

Acute exercise increased leukocytes by 50.5% [95% CI, 48.2–52.8] and CRP by 7.7% [95% CI, 5.5–10.0]; leukocytes remained elevated after two hours, but CRP recovered to baseline. Within exercise, interferon-γ rose by 13.1% [95% CI, 9.2–17.3], but within two hours, it dropped below baseline.

Following acute exercise, tumor necrosis factor-α (12.9% [95% CI, 8.4–17.4]), interleukin-2 (22.8% [95% CI, 17.5–28.5]), and interleukin-6 (42.4% [95% CI, 36.5–48.5]) also increased and remained elevated after 2 hours, whereas interleukin-10 dropped by 9.2% [95% CI, −14.1 to –4.0] and returned to baseline after two hours.

When compared to usual treatment, high-intensity interval training did not significantly change these inflammatory markers during a 12-week period. Overall, while 12 weeks of HIIT did not produce long-lasting anti-inflammatory improvements, acute, intense exercise temporarily increased inflammatory markers in stable individuals with CAD. 

Source:

Kristiansen, J., Kristensen, S. D., Hvas, A.-M., Ellingsgaard, H., Mohr, M., Grove, E. L., & Sjúrðarson, T. (2026). Effects of acute exercise and 12-week high-intensity interval training on inflammatory biomarkers in stable coronary artery disease: A randomized controlled trial. Journal of the American Heart Association, 15(4), e042256. https://doi.org/10.1161/JAHA.125.042256