Long-term effects of high-intensity interval training in heart transplant recipients: A 5-year follow-up study of a randomized controlled trial

Abstract

Background: Previous studies have demonstrated that high-intensity interval training (HIT) is superior to moderate-continuous exercise in general and in cardiovascular diseases. Recently, we also found HIT safe and efficient after heart transplantation (HTx). This study reports the 5-year long-term effects.

Design and methods: Forty-one HTx patients who had completed the previous 12-month randomized controlled trial, comparing HIT intervention with usual care, were eligible. In particular, we measured VO_2peak , muscular capacity, intravascular ultrasound, and questionnaires measuring physical and mental health.

Results: The baseline mean±SD values were as follows: age; 49.1±16.5 years, men; 68%, time since HTx: 4.1±2.2 years. Within the HIT group, initial VO_2peak increased significantly from 27.7±5.7 to 31.2±5.3 mL/kg/min. However, during the next 4 years, VO_2peak decreased to 26.0±6.2 mL/kg/min. The control group showed slightly decreasing VO_2peak values during the entire 5-year period. The HIT group reported significantly less anxiety symptoms, but there were no long-term differences in VO_2peak , muscular capacity, or cardiac allograft vasculopathy between the groups. The similar VO_2peak values correspond to our findings of similar everyday activity.

Conclusion: Our findings suggest that intermittent periods of HIT may be necessary to maintain the initial benefits gained from the intervention. However, HIT probably reduces the burden of anxiety, which is a frequent health issue following HTx.

Keywords: anxiety; clinical trial; exercise; exercise test; heart transplantation; physical fitness; rehabilitation; time.