Effect of high-intensity training versus moderate training on peak oxygen uptake and chronotropic response in heart transplant recipients: a randomized crossover trial.
Dall CH, Snoer M, Christensen S, et al.American journal of transplantation 2014; 14(10):2391-9
Aims
To investigate the effect of high intensity interval training (HIIT) versus continued moderate (CON) exercise on peak oxygen uptake and chronotropic response in adult heart transplant recipients.
Interventions
Participants were randomised to the HIIT or CON arms of the trial. Each group consisted of supervised sessions three times a week for 12 weeks and began with a 10 minute warm up and 10 minute cool down. The HIIT group received 16 minute interval training with intervals of 4,2 and 1 minutes at >80% of VO2 peak, separated by a 2-min active rest period with the total session time being 32 minutes. The CON group received a session of biking for 45 minutes at 60-70% of VO2peak.
Participants
17 clinically stable heart transplant recipients.
Outcomes
The primary outcome was VO2peak and the secondary outcomes were exercise training including blood pressure, heart rate (HR) peak, HR rest, HR reserve, HR recovery and workload.
Follow-up
12 weeks after 5 months washout and again after the second 12 week intervention period.
CET Conclusions
This is an interesting report of a randomised, cross-over study of 12 weeks high intensity interval training (HIIT) versus moderate exercise (45 minutes cycling) with a washout of 5 months during which participants continued with their usual lifestyle. Participants were stable heart transplant recipients who were at least 12 months posttransplant. Sample size calculations indicated that 16 patients were needed and 17 patients were included in the trial. Outcome assessors were blinded to the intervention and patients were asked not to discuss their exercise regimes with the assessors. There was a significant increase in VO2peak after both training regimes but the increase after HIIT was significantly greater. The change scores were also significantly higher after HIIT for peak power output, peak heart rate and heart rate reserve. No significant differences in change scores were found for systolic or diastolic blood pressure, or any of the other outcomes. The authors showed that the effects of exercise were lost during the washout period and they reported that there were no adverse events.
Data analysis
Available case analysis
Trial registration
ClinicalTrials.gov – NCT01914406