One year of high-intensity interval training improves exercise capacity, but not systemic arterial function in stable heart transplant recipients

Abstract

Background: There is a high prevalence of hypertension and coronary allograft vasculopathy in heart transplant (HTx) recipients. High‐intensity interval training (HIIT) improves exercise capacity and lower blood pressure in hypertensive patients, but the effect of HIIT on arterial properties in stable HTx recipients is unknown. We aimed to investigate the effect of HIIT on arterial properties in stable HTx recipients. Methods: Thirty‐two stable HTx recipients (1‐8 years post‐transplant) were randomized 1:1 to either HIIT (4 × 4 minutes at 90‐95% of peak heart rate (HR) 3 times per week for 8×3 weeks throughout one year) or control group. Cardiopulmonary exercise tests and tonometric recordings were performed at baseline and follow‐up. Aortic root pressure and flow were obtained by calibrated carotid arterial pulse traces and aortic root Doppler flow recording, and used as input in mathematical models of the arterial system. Arterial properties were described by peripheral vascular resistance (TVR), proximal aortic stiffness (characteristic impedance, Z0), total arterial compliance (C) and arterial elastance (Ea). Results: HIIT increased VO2peak from 27.6±4.8 at baseline to 30.6±4.5 ml/kg/min at follow‐up, while the control group remained unchanged (30.5±7.2 vs. 30.2±6.6 ml/kg/min, p=0.006 for difference between the groups at follow‐up). Neither blood pressure nor arterial properties were influenced after one year of HIIT (Table). (Table presented) Conclusions: Whereas HIIT is feasible in HTx recipients and effectively improves exercise capacity, it does not alter blood pressure or systemic arterial function significantly.