Effects of Acute Exercise and 12-Week High-Intensity Interval Training on Inflammatory Biomarkers in Stable Coronary Artery Disease: A Randomized Controlled Trial

Background: Persistent low-grade inflammation contributes to coronary artery disease (CAD), but how acute vigorous exercise and structured training affect systemic inflammatory biomarkers in stable CAD remains unclear. We evaluated the acute response to a single vigorous bout and the effects of a 12-week high-intensity interval training program on systemic inflammation in patients with stable CAD.

Methods: In 168 patients with stable CAD, blood samples were collected before, immediately after, and 2 hours after a maximal incremental cycling test. Participants were then randomized to 12 weeks of high-intensity interval training or standard care; 142 completed follow-ups. High-sensitivity CRP (C-reactive protein), leukocytes, interleukin-2, interleukin-6, interleukin-10, interferon-γ, and tumor necrosis factor-α were measured at baseline, week 6, and week 12.

Results: Acute exercise elevated CRP by 7.7% [95% CI, 5.5-10.0] and leukocytes by 50.5% [95% CI, 48.2-52.8]; CRP returned to baseline by 2 hours, whereas leukocytes remained elevated. Interferon-γ increased by 13.1% [95% CI, 9.2-17.3] following exercise but fell below baseline after 2 hours. 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 following acute exercise and stayed elevated after 2 hours, while interleukin-10 decreased by 9.2% [95% CI, -14.1 to -4.0] and returned to baseline after 2 hours. Over 12 weeks, high-intensity interval training did not significantly alter these inflammatory markers compared with standard care.

Conclusions: Acute strenuous exercise induces transient increases in inflammatory markers in stable CAD, which begin to resolve within 2 hours. In this optimally treated cohort, regular high-intensity interval training did not produce a sustained anti-inflammatory effect.