Effects of Acute Exercise and 12-Week High-Intensity Interval Training on Inflammatory Biomarkers in Stable Coronary Artery Disease: A Randomized Controlled Trial
Question
How do acute strenuous exercise and 12 weeks of supervised high-intensity interval training affect systemic inflammatory biomarkers in patients with stable coronary artery disease?
Summary
Patients with stable coronary artery disease completed an acute maximal cycling test and were then randomized to supervised rowing HIIT or standard care for 12 weeks. Acute strenuous exercise temporarily increased several inflammatory biomarkers, with partial resolution by 2 hours. Despite high adherence and previously reported fitness gains, 12 weeks of HIIT did not reduce resting inflammatory markers compared with standard care in this optimally treated, low-inflammation CAD cohort.
Methodology
- Adults with stable coronary artery disease at least 12 months after myocardial infarction or revascularization, able to perform strenuous exercise.
- 168 participants.
- Rowing ergometer.
- Work intervals: <=2 minutes; session 7 calibration used six 2-minute all-out intervals.
- Recovery: 1:1 work-to-rest; session 7 used 2-minute recovery.
- Intensity: Target power calibrated from mean power across six 2-minute all-out intervals; target reevaluated at sessions 16 and 25.
- Approximately 30 minutes with 6-minute warm-up and 4- to 5-minute cool-down when exhaustive bouts were scheduled.
- 3 sessions per week.
- 12 weeks.
- Single-center randomized controlled trial with an acute exercise biomarker substudy followed by 12-week HIIT versus standard care.
- High-sensitivity CRP, Leukocyte count, Inflammatory cytokines, and Cardiorespiratory fitness association were tracked.
Outcomes
Acute inflammatory response
Acute maximal exercise increased CRP by 7.7%, leukocytes by 50.5%, IFN-gamma by 13.1%, TNF-alpha by 12.9%, IL-2 by 22.8%, and IL-6 by 42.4%; IL-10 decreased by 9.2%.
Reported acute changes were significant, generally P<0.001 for main immediate contrasts.
Two-hour biomarker recovery
CRP and IL-10 returned to baseline by 2 hours, IFN-gamma fell below baseline, while TNF-alpha, IL-2, IL-6, and leukocytes remained elevated.
Examples: IL-6 remained 12.4% above baseline (P<0.001); leukocytes remained 12.4% above baseline (P<0.001).
12-week inflammatory biomarkers
HIIT did not significantly alter resting inflammatory markers compared with standard care over 12 weeks.
No statistically significant time-by-group effects were reported for the main inflammatory biomarker comparisons.
Adherence
The supervised rowing HIIT program had high protocol adherence.
Adherence across 36 sessions was 97%.
Fitness-biomarker correlation
Change in absolute peak oxygen uptake was not significantly associated with inflammatory biomarker changes in HIIT participants.
IL-10 correlation r=0.29, P=0.081; other biomarkers |r|<=0.12 and not significant.
Insights
- Short-term HIIT should not be presented as reliably lowering resting inflammatory biomarkers in well-treated stable CAD patients.
- High-risk clinical HIIT protocols used familiarization, close supervision, power calibration, and immediate modification for discomfort.
- Acute hard exercise can transiently raise inflammatory markers, so timing of biomarker measurement relative to exercise matters.
Limitations
- Circulating biomarkers may not reflect vascular or plaque-level inflammation.
- Acute exercise test was not repeated after 12 weeks, so training effects on acute inflammatory spikes are unknown.
- Medication, diet, stress, illness, and seasonal factors may have contributed to biomarker variability.
- Inflammatory markers were measured only at weeks 6 and 12.
- Acute responses were prespecified in the ethics protocol but not registered as ClinicalTrials.gov outcomes.
- Single-center structured health care setting with high adherence limits generalizability.
- Inflammatory endpoints were secondary, and sex-specific analyses had few female participants.
- Twelve weeks may have been insufficient for resting inflammation changes.
Safety
- No specific adverse event totals were reported in the extracted article text.
- Patients unable to perform strenuous exercise or with higher-risk cardiac conditions were excluded.
- All training sessions were supervised and included monitoring for early discomfort.
- Resistance or interval duration was modified immediately if needed.
- Authors noted vigorous exercise can temporarily elevate cardiovascular risk in sedentary CAD patients.