Cardiorespiratory fitness and walking ability in subacute stroke patients

Objectives: To evaluate the cardiorespiratory fitness of subacute stroke patients and to determine whether reduced fitness is associated with gait performance. Design: Descriptive, cross-sectional study. Setting: Rehabilitation hospital. Participants: Seventeen patients in an inpatient rehabilitation unit who had mild to moderate gait impairments after a recent (less than or equal to7wk) stroke. All subjects could walk at least 3m alone or with an aid but with no standby assistance. Interventions: Not applicable. Main Outcome Measures: Peak and submaximal cardiorespiratory responses were measured during semirecumbent leg cycling exercise. Walking velocity and endurance were assessed with 10-m and 6-minute walk tests, respectively. Results: Peak oxygen uptake (Vo(2)peak) was 1.15 +/- 0.36L/ min, which was only 50% of the Vo(2)peak reported in the literature for a healthy, age-matched group. Maximal walking velocity (1.02 +/- 0.28 m/s) and endurance (294.1+/-120.2m) were also approximately 50% of an aged-matched healthy group. Pearson product-moment correlations revealed that 6-minute walking endurance was strongly associated with self-selected walking velocity (R=.91) and measures of peak cardiorespiratory fitness (R=.84). Conclusions: Cardiorespiratory fitness was markedly impaired within 7 weeks after a stroke. Although muscle weakness and loss of coordination are the primary impairments that affect gait after a stroke, impaired cardiorespiratory fitness may secondarily affect gait performance by limiting walking endurance. To address this secondary impairment, current rehabilitation interventions can incorporate assessment of cardiorespiratory fitness status and aerobic exercise training for persons after stroke.