Evaluation of three measures of cardiorespiratory fitness in independently ambulant stroke survivors

ABSTRACT

Measuring cardiorespiratory fitness (CRF) in the stroke population is challenging. Currently, the recommended method is a graded exercise test (GXT) on an ergometer such as a treadmill or cycle, which may not always be possible. We investigated whether walking tests such as the six-minute walk test (6MWT) and the shuttle walk test (SWT) may be appropriate indicators of CRF in the stroke population. Twenty-three independently ambulant stroke survivors (11 men, age 61.5 ± 18.4 years) within one-year post stroke performed the 6MWT, SWT, and cycle GXT, during which peak oxygen consumption (VO_2peak) and heart rate (HR_peak) were recorded. There were no differences (p > 0.05) in mean VO_2peak among the three tests (min-max: 17.08–18.09 mL kg⁻¹ min⁻¹). For individuals, small discrepancies in VO_2peak between the 6MWT and other tests were greater with higher fitness levels. HR_peak was significantly (p = 0.005) lower during the 6MWT. Correlations between VO_2peak and performance measures within each test were high (6MWT VO_2peak and distance: r = 0.78, SWT VO_2peak and shuttles: r = 0.73, cycle GXT VO_2peak and workload: r = 0.77) suggesting the performance measures may be clinically useful as proxy measures of CRF. Common comorbidities, such as lower-limb joint pain and poor balance, and participant’s fastest walking speed, should inform the choice of CRF test.

Declaration of interest

The authors have no conflicts of interest to declare.

Additional information

Funding

This work was supported by the Australian Research Council [Future Fellowship]; Heart Foundation; Hunter Medical Research Institute [Estate of the late Stephen James Fairfax Award]; National Stroke Foundation; Australian National Health and Medical Research Council [Career Development Fellowship APP1035465]; John Hunter Hospital Charitable Trust; Emlyn and Jennie Thomas Postgraduate Medical Research Scholarship.