RESUMEN
OBJECTIVE: To assess the effects of high-intensity interval training (HIIT) on physical, mental, and cognitive functioning after stroke. DESIGN: The HIIT Stroke Study was a single-blind, multicenter, parallel-group randomized controlled trial. SETTING: Specialized rehabilitation units at 3 Norwegian hospitals. PARTICIPANTS: Adult stroke survivors (N=70) 3 months to 5 years after a first-ever stroke. Mean age was 57.6±9.2 years and 58.7±9.2 years in the intervention and control groups, respectively. INTERVENTIONS: Participants were randomized to standard care in combination with 4×4 minutes of treadmill HIIT at 85%-95% of peak heart rate or standard care only. OUTCOMES: Outcomes were measured using physical, mental, and cognitive tests and the FIM and Stroke Impact Scale. Linear mixed models were used to analyze differences between groups at posttest and 12-month follow-up. RESULTS: The intervention group showed a significant treatment effect (95% confidence interval [CI]) from baseline to posttest on a 6-minute walk test of 28.3 (CI, 2.80-53.77) meters (P=.030); Berg Balance Scale 1.27 (CI, 0.17-2.28) points (P=.025); and Trail Making Test Part B (TMT-B; -24.16 [CI, -46.35 to -1.98] s, P=.033). The intervention group showed significantly greater improvement on TMT-B at the 12-month follow-up (25.44 [CI, -49.01 to -1.87] s, P=.035). The control group showed significantly greater improvement in total Functional Independence Measure score with a treatment effect of -2.37 (CI, -4.30 to -0.44) points (P=.016) at 12-month follow-up. No significant differences were identified between groups on other outcomes at any time point. CONCLUSIONS: HIIT combined with standard care improved walking distance, balance, and executive function immediately after the intervention compared with standard care only. However, only TMT-B remained significant at the 12-month follow-up.