Abstract Body:
INTRODUCTION: Cognitive impairment, mood disorders, and reduced serum BDNF levels are common in stroke patients. Previous studies suggest that aerobic exercise improves these outcomes by enhancing oxygenation. Herein, the authors compare the effectiveness of high-intensity interval training (HIIT) with low (LIT) and moderate (MIT) intensities and usual activity (UA) in stroke patients.


METHODS: We systematically searched PubMed, Cochrane, Embase, and Scopus databases for studies comparing HIIT with LIT, MIT, or UA in stroke patients. We evaluated change from baseline in cognitive improvement, mood disorders including anxiety and depression, and serum BDNF levels. Subgroup analyses were conducted based on stroke onset and exercise intensity, and separate analyses compared HIIT with each control group to assess cognitive improvement at different intensity levels.

RESULTS: A total of ten non-randomized and randomized studies were included in the analysis. Seven studies involving 373 patients showed no statistically significant difference in cognitive improvement between HIIT and the control group (std. MD 0.09; 95% CI -0.13 to 0.30; p=0.43). Separate analyses also revealed no significant differences between HIIT and LIT (std. MD -0.06; 95% CI -0.54 to 0.41; p=0.60), HIIT and MIT (std. MD 0.03; 95% CI -0.30 to 0.37; p=0.85), and HIIT and UA (std. MD 0.20; 95% CI -0.13 to 0.53; p=0.23). Subgroup analysis for chronic stroke did not show significant differences either (std. MD 0.07; 95% CI -0.19 to 0.34; p=0.58). Additionally, an analysis of four studies involving 281 patients found no significant difference in mood disorders (std. MD -0.21; 95% CI -0.62 to 0.21; p=0.33). A separate analysis of four studies with 130 patients also revealed no significant difference in serum BDNF levels between the two groups (std. MD 3.65; 95% CI -0.37 to 7.67; p=0.08). However, subgroup analysis indicated that serum BDNF levels were 3.32 ng/mL higher in the MIT group compared to the HIIT group.

CONCLUSION: High-intensity-interval training does not demonstrate a significant advantage in cognitive improvement, mood disorders, or serum BDNF levels when compared to different exercise intensities. However, MIT is associated with increased serum BDNF levels compared to HIIT. Future robust RCTs are needed to compare different exercise intensities and durations to provide more conclusive results.