Introduction: Aerobic exercise (AE) has been shown to be efficacious in improving cardiovascular function following stroke; however, it is not routinely incorporated into post-stroke rehabilitation. Two modes of aerobic stationary bicycling (forced and voluntary rate) were applied to individuals with chronic stroke as part of a study to determine the effects of AE on motor recovery and cardiovascular function, compared to a no exercise control group. We hypothesized that both modes of AE training would elicit similar improvements in cardiorespiratory function, while no improvement would be evident in the control group.
Methods: Twenty-five individuals with chronic stroke were randomized to complete forced-rate aerobic exercise (FE, n=8), voluntary-rate aerobic exercise (VE, n=8), or no AE (n=9). All AE sessions were 45 minutes in length and occurred on a semi-recumbent cycle ergometer. All participants also completed upper extremity task practice, as the study was investigating the neuroplastic effects of AE on motor recovery. Participants in all groups underwent time-matched interventions, 3 times per week for 8 weeks. An exercise stress test and six-minute walk test were completed at baseline and end of treatment (EOT).
Results: Individuals in the FE and VE groups exercised at mean intensities of 56.5% and 55.9% of heart rate reserve, respectively. Peak oxygen consumption improved significantly from baseline to EOT for the FE and VE groups by 1.1 and 2.4 mL/kg/min, respectively, with no change in the control group. Ventilatory threshold improved by a mean of 1.1 mL/kg/min in FE participants, was unchanged in VE participants, and decreased by 1.5 mL/kg/min for those in the control group. Heart rate (HR) response during each stage of the stress test improved for 75% of the FE and VE participants and 44% of control group participants. During the 6-minute walk test, the FE, VE, and control groups improved by a mean of 190, 132, and 90 feet, respectively.
Conclusions: Individuals with chronic stroke tolerated both modes of intensive AE. The 8-week intervention elicited improvements in peak oxygen consumption, HR response, and activity tolerance. Both FE and VE were efficacious in improving cardiovascular fitness, while simultaneously enhancing motor recovery.