Effects of High-Intensity Interval Training After Stroke (the HIIT-Stroke Study): A Multicenter Randomized Controlled Trial.

Abstract

To examine if 8 weeks of high-intensity interval training (HIIT) in addition to standard care would increase and maintain peak oxygen uptake (Vo_2peak) more than standard care alone in patients with stroke. This was a single-blind, multicenter, parallel group, randomized controlled trial. Specialized rehabilitation units at 3 Norwegian hospitals. Participants (N=70), 3 months to 5 years after first-ever stroke, were randomly assigned to the intervention group (n=36) or the control group (n=34); 42% were women, mean age was 57.6±9.3 years, mean time post stroke was 26.4±14.5 months. The intervention was 8 weeks: 3 times a week with HIIT treadmill training with work periods of 4 × 4 minutes at 85%-95% of peak heart rate interspersed with 3 minutes of active recovery at 50%-70% of peak heart rate. The control group received standard care according to national guidelines. The primary outcome, analyzed by intention-to-treat, was Vo_2peak measured as liters per minute 12 months after inclusion. Secondary outcome measures were blood pressure and blood profile. Mean baseline Vo_2peak was 2.63±1.08 L·min^-1 vs 2.87±0.71 L·min^-1, while at 12 months Vo_2peak was 2.70±1.00 L·min^-1 vs 2.67±0.76 L·min^-1 (P=.068) in the intervention and control groups, respectively. There was a significant and greater improvement in the intervention group compared with the control group at 12 months in 3 of 6 secondary outcomes from the peak test but no significant differences for blood pressure or blood profile. The HIIT intervention, which was well-tolerated in this sample of well-functioning survivors of stroke, was not superior to standard care in improving and maintaining Vo_2peak at the 12-month follow-up. However, secondary results from the peak test showed a significant improvement from before to immediately after the intervention.