High-intensity aerobic interval training for patients 3-9 months after stroke: a feasibility study

Background and purpose: High-intensity aerobic interval training (AIT) has shown to be beneficial in patients with cardiac and pulmonary diseases. Presumably, patients with stroke also benefit from such treatment. However, the feasibility and potential efficacy of high-intensity AIT should be investigated for patients early after stroke.

Methods: This was a single-group, pre-test-post-test, intervention study. The intervention consisted of a 6-week high-intensity AIT programme, performed twice a week. The AIT comprised 4 × 4-minute intervals, at 85-95% of peak heart rate, interrupted by 3-minute active breaks. Adherence to the protocol, compliance and adverse events were registered to assess feasibility. Cardiorespiratory fitness and functional outcomes were assessed before and after the intervention and at 6 and 12 weeks follow-up.

Results: Ten men and five women (mean age 70.0 ± 7.7; range 61-85 years) with mild to moderate stroke were included, 3-9 months after onset. One patient was diagnosed with cancer during follow-up. There were three minor events, but no serious adverse events occurred. All patients accomplished all training sessions and reached the 85% intensity level, except one patient who discontinued the last session. The mean peak oxygen uptake showed no significant improvement from pre-treatment, 28.7 ± 3.8 ml kg(-1) min(-1), to post-treatment, 29.6 ± 3.6 ml kg(-1) min(-1), p = 0.189, whereas the mean 6-minute walk test improved from 410.7 ± 101.4 m to 461.0 ± 99.6 m, p = 0.001, and the median (interquartile range) Rivermead Motor Assessment Scale improved from 12.0 (11.0-13.0) to 13.0 (11.0-13.0) points, p = 0.100. These improvements continued after the intervention was concluded.

Conclusions: This study has shown that high-intensity AIT is feasible for a selected group of stroke patients. However, the training should be accomplished in line with the American College of Sports Medicine guidelines for high-risk populations to ensure safety. The participants achieved a clinically highly significant improvement in walking distance. This intervention should be tested out in a randomized controlled trial to assess if it is superior to other interventions.