Effects of cardiovascular exercise early after stroke: systematic review and meta-analysis

Background: Previous studies have shown the beneficial effects of aerobic exercise in chronic stroke. Most motor and functional recovery occurs in the first months after stroke. Improving cardiovascular capacity may have potential to precipitate recovery during early stroke rehabilitation. Currently, little is known about the effects of early cardiovascular exercise in stroke survivors. The aim of this systematic review was to evaluate the effectiveness of cardiovascular exercise early after stroke. Methods: A systematic literature search was performed. For this review, randomized and non-randomized prospective controlled cohort studies using a cardiovascular, cardiopulmonary or aerobic training intervention starting within 6 months post stroke were considered. The PEDro scale was used to detect risk of bias in individual studies. Inter-rater agreement was calculated (kappa). Meta-analysis was performed using a random-effects model. Results: A total of 11 trials were identified for inclusion. Inter-rater agreement was considered to be "very good" (Kappa: 0.81, Standard Error: 0.06, CI95%: 0.70-0.92), and the methodological quality was "good" (7 studies) to "fair" (4 studies). Peak oxygen uptake data were available for 155 participants. Pooled analysis yielded homogenous effects favouring the intervention group (standardised mean difference (SMD) = 0.83, CI95% = 0.50-1.16, Z = 4.93, P < 0.01). Walking endurance assessed with the 6 Minute Walk Test comprised 278 participants. Pooled analysis revealed homogenous effects favouring the cardiovascular training intervention group (SMD = 0.69, CI95% = 0.45-0.94, Z = 5.58, P < 0.01). Gait speed, measured in 243 participants, did not show significant results (SMD = 0.51, CI95% = -0.25-1.26, Z = 1.31, P = 0.19) in favour of early cardiovascular exercise. Conclusion: This meta-analysis shows that stroke survivors may benefit from cardiovascular exercise during sub-acute stages to improve peak oxygen uptake and walking distance. Thus, cardiovascular exercise should be considered in sub-acute stroke rehabilitation. However, concepts to influence and evaluate aerobic capacity in severely affected individuals with sub-acute stroke, as well as in the very early period after stroke, are lacking. Further research is needed to develop appropriate methods for cardiovascular rehabilitation early after stroke and to evaluate long-term effects of cardiovascular exercise on aerobic capacity, physical functioning, and quality of life.