An 8-week Forced-rate Aerobic Cycling Program Improves Cardiorespiratory Fitness in Persons With Chronic Stroke: A Randomized Controlled Trial

Abstract

Objective: To examine the cardiorespiratory effects of a forced-rate aerobic exercise (FE) intervention among individuals with chronic stroke compared with an upper extremity repetitive task practice (UE RTP) control group.

Design: Secondary analysis of data from a randomized controlled trial.

Setting: Research laboratory.

Participants: Individuals with chronic stroke (N=60).

Interventions: Participants completed 24 sessions of FE followed by RTP (FE+RTP, N=30) or time matched RTP alone (N=30). The FE+RTP group was prescribed exercise at 60%-80% of heart rate reserve on a motorized stationary cycle ergometer for 45 minutes followed by 45 minutes of RTP. The control group completed 90 minutes of RTP.

Main outcome measures: Metabolic exercise stress tests on a cycle ergometer were conducted at baseline and post-intervention. Outcomes included peak oxygen consumption (peak V̇o₂) and anaerobic threshold (AT).

Results: Fifty participants completed the study intervention and pre/post stress tests. The FE+RTP group demonstrated significantly greater improvements in peak V̇o₂ from 16.4±5.7 to 18.3±6.4 mL/min/kg compared with the RTP group (17.0±5.6 to 17.2±5.6 mL/min/kg, P=.020) and significantly greater improvements in AT from 10.3±2.8 to 11.5±3.6 mL/min/kg compared with the RTP group (10.8±3.9 to 10.4±3.2 mL/min/kg, P=.020). In analyzing predictors of post-intervention peak V̇o₂, the multivariable linear regression model did not reveal a significant effect of age, sex, body mass index, or beta blocker usage. Similarly, bivariate linear regression models for the FE group only did not find any exercise variables (aerobic intensity, power, or cycling cadence) to be significant predictors of peak V̇o₂.

Conclusions: While the aerobic exercise intervention was integrated into rehabilitation to improve UE motor recovery, it was also effective in eliciting significant and meaningful improvements in cardiorespiratory fitness. This novel rehabilitation model may be an effective approach to improve motor and cardiorespiratory function in persons recovering from stroke.

Trial registration: ClinicalTrials.gov NCT03819764.

Keywords: Aerobic exercise; Cardiopulmonary exercise test; Cardiorespiratory fitness; Rehabilitation.