High-intensity interval training enhances mitochondrial bioenergetics of platelets in patients with heart failure

Objective: Exercise improves cardiopulmonary fitness and reduces the risk of vascular thrombosis in patients with cardiovascular diseases. In platelets, mitochondria carry out cellular bioenergetics and thrombogenesis. This study aimed to elucidate the effect of high-intensity interval training (HIIT) on systemic aerobic capacity and platelet mitochondrial bioenergetics in patients with heart failure (HF). Methods: Thirty-four randomly selected HF patients engaged in HIIT (3-min intervals at 40% and 80% of VO_2peak, n = 17) for 30 min/day, 3 days/week for 12 weeks, or to a control group that received general healthcare (GHC; n = 17). Systemic aerobic capacity (i.e., peak O₂ consumption, VO_2peak) and platelet mitochondrial O₂ consumption rate (OCR) in the HF patients were measured through automatic gas analysis and high-resolution respirometry, respectively. Results: The HIIT group exhibited higher VO_2peak and O₂ uptake efficiency slope and lower V_E-VCO₂ slope after 12-week intervention, compared to those of the GHC group. Moreover, the HIIT regimen increased the maximal and reserve OCR capacities, enhanced the Complex I- and II-mediated OCRs, and elevated the bioenergetic health index in platelet mitochondria; however, these effects were not observed with the GHC regimen. Additionally, the VO_2peak levels were positively correlated with the maximal and reserve OCR capacities and Complex I- and II-mediated OCRs in platelet mitochondria. Conclusion: Platelet mitochondrial function is an ideal bioenergetic indicator in patients with HF. HIIT for 12 weeks elevates platelet mitochondrial OCRs via increasing Complex I and II activities. Moreover, systemic aerobic capacity is positively associated with platelet mitochondrial OCRs in HF patients.