Cardiorespiratory responses during the 6-minute walk and ramp cycle ergometer tests and their relationship to physical activity in stroke.
OBJECTIVE
The 6-minute walk test (6MWT) is used to measure exercise capacity after stroke. We sought to compare cardiorespiratory responses during the 6MWT with responses to a ramp cycle ergometer test (CET) in community-dwelling individuals with stroke. A secondary objective was to determine the relationship between cardiorespiratory responses during each test and daily physical activity.


METHODS
Participants completed 3 evaluation sessions. The CET and 6MWT were conducted in 2 separate sessions at least 72 hours apart. Participants wore a portable gas analysis unit (Cosmed K4b2), which also measured heart rate (HR) during the 6MWT. A uniaxial accelerometer (activPAL) was used to measure time spent upright (standing and stepping) over 5 days as an estimate of daily physical activity.


RESULTS
Complete CET and 6MWT data were obtained for 16 participants (14 men), a mean ± standard deviation of 2.0 ± 1.1 years after stroke and 71.1 ± 9.7 years of age. Compared with the 6MWT, the CET elicited a higher VO(2peak) (P = .032), VCO(2peak) (P = .005), respiratory exchange ratio (P = .015), and self-reported perceived breathing (P < .0001) and leg heaviness (P < .0001) at test completion and a lower HR(peak) (P = .029). Except for the first minute, VO(2) during the 6MWT was, on average, 80% to 85% of VO(2peak) from the CET. Among 15 participants, average time spent upright per day was not significantly associated with 6MWT distance (r = 0.447, P = .096) or VO(2peak) from the CET (r = 0.388, P = .153).


CONCLUSIONS
Exercise intensity achieved during the 6MWT appeared sufficiently high for aerobic training, assuming CET VO(2peak) accurately reflects aerobic capacity. The 6MWT may be useful for prescribing aerobic exercise poststroke.
1University of Toronto, ON, Canada.
Nancy M
NM
Salbach
Dina
D
Brooks
Julia
J
Romano
Lynda
L
Woon
Thomas E
TE
Dolmage
D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D016552:Ergometry; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology*; D011446:Prospective Studies; D012123:Pulmonary Ventilation / Q000502:physiology*; D020521:Stroke / Q000503:physiopathology*; D016138:Walking / Q000502:physiology*
6-minute walk test; aerobic exercise; outcome assessment; physical activity; progressive exercise test; stroke