title: Effect of high-intensity training versus moderate training on peak oxygen uptake and chronotropic response in heart transplant recipients: a randomized crossover trial.
abstract: In heart transplant (HTx) recipients, there has been reluctance to recommend high-intensity interval training (HIIT) due to denervation and chronotropic impairment of the heart. We compared the effects of 12 weeks' HIIT versus continued moderate exercise (CON) on exercise capacity and chronotropic response in stable HTx recipients >12 months after transplantation in a randomized crossover trial. The study was completed by 16 HTx recipients (mean age 52 years, 75% males). Baseline peak oxygen uptake (VO2peak ) was 22.9 mL/kg/min. HIIT increased VO2peak by 4.9 ± 2.7 mL/min/kg (17%) and CON by 2.6 ± 2.2 mL/kg/min (10%) (significantly higher in HIIT; p < 0.001). During HIIT, systolic blood pressure decreased significantly (p = 0.037) with no significant change in CON (p = 0.241; between group difference p = 0.027). Peak heart rate (HRpeak ) increased significantly by 4.3 beats per minute (p = 0.014) after HIIT with no significant change in CON (p = 0.34; between group difference p = 0.027). Heart rate recovery (HRrecovery ) improved in both groups with a trend toward greater improvement after HIIT. The 5-month washout showed a significant loss of improvement. HIIT was well tolerated, had a superior effect on oxygen uptake, and led to an unexpected increase in HRpeak accompanied by a faster HRrecovery . This indicates that the benefits of HIIT are partly a result of improved chronotropic response.
authors.affiliation: Department of Cardiology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark; Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark.
authors.forename: C H
authors.initials: CH
authors.lastname: Dall
authors.forename: M
authors.initials: M
authors.lastname: Snoer
authors.forename: S
authors.initials: S
authors.lastname: Christensen
authors.forename: T
authors.initials: T
authors.lastname: Monk-Hansen
authors.forename: M
authors.initials: M
authors.lastname: Frederiksen
authors.forename: F
authors.initials: F
authors.lastname: Gustafsson
authors.forename: H
authors.initials: H
authors.lastname: Langberg
authors.forename: E
authors.initials: E
authors.lastname: Prescott
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure; D018592:Cross-Over Studies; D015444:Exercise; D005260:Female; D006339:Heart Rate; D016027:Heart Transplantation; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism*
chemical_list: D010100:Oxygen
keywords: clinical research/practice; clinical trial design; heart (allograft) function/dysfunction; heart disease; heart transplantation/cardiology