Dall CH, et al. – The authors 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. In this study the 5–month washout showed a significant loss of improvement. high–intensity interval training (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.