Rollator use does not consistently change the metabolic cost of walking in people with chronic obstructive pulmonary disease.

OBJECTIVES: To (1) evaluate whether the use of a rollator changed metabolic cost during a controlled walking task, and (2) explore relationships between the difference in dyspnea and metabolic cost associated with rollator use. DESIGN: Single-group interventional study in which patients completed 2 corridor walks: 1 without and 1 with a rollator, at the same individualized constant speed. SETTING: Rehabilitation hospital. PARTICIPANTS: Patients with chronic obstructive pulmonary disease (N=15; 10 men; median age [interquartile range; IQR]=69 [12]y; forced expiratory volume in 1 second=42 [20]% predicted). INTERVENTION: Rollator use. MAIN OUTCOME MEASURES: Oxygen uptake, converted to metabolic equivalent units (METs), and minute ventilation were measured throughout both tasks using a portable gas analysis system; dyspnea and arterial oxygen saturation (SpO(2)) were collected on completion. RESULTS: Median [IQR] walk speed [IQR] was 48 (10)m/min. Walking with a rollator, compared with walking without, reduced dyspnea (median [IQR]=1.0 [1.5] vs 2.0 [2.0]; P=.01) without changing energy expenditure (median [IQR]=2.8 [1.2] vs 3.2 [0.9] METs; P=.65), minute ventilation (median [IQR]=30.3 [9.6] vs 27.7 [9.9]L/min; P=.50), or SpO(2) (median [IQR]=92 [8]% vs 94 [10]%; P=.41). The association between the reduction in dyspnea and any difference in energy expenditure related to rollator use was of borderline significance (r(s)=.50; P=.06). Six of the 8 participants who experienced a reduction in dyspnea also demonstrated a reduction in the metabolic cost of walking. CONCLUSIONS: The mechanism responsible for the amelioration in dyspnea during rollator-assisted walking is multifactorial. A reduction in the metabolic cost of walking may play a part in some, but not all, patients.

The 6-min walk test: responses in healthy Canadians aged 45 to 85 years.

We sought to describe responses to the 6-min walk test (6MWT) in healthy Canadian adults in order to facilitate interpretation of its results in patient populations. Seventy-seven healthy Canadians aged 45 to 85 years (65 ± 11 years, 40 females) completed this study. During a single visit, three 6MWTs were undertaken. The main outcome measure was 6-min walk distance (6MWD). Age, gender, height, and weight were recorded. In 61 (79%) participants, cardiorespiratory variables were collected during the third 6MWT using a calibrated portable gas analysis system. The 6MWD increased between the first and second test (615 ± 96 to 639 ± 98 m; p < 0.001) with no further improvement on the third test (638 ± 99 m; p = 0.945). The best 6MWD from the first 2 tests was 640 ± 99 m (range 416 to 880 m). A greater 6MWD was achieved by males compared with females (672 ± 94 vs. 611 ± 93 m; p = 0.005). The following equation accounted for 49% of the variance in 6MWD: 6MWD = 970.7 + (-5.5 × age) + (56.3 × gender), where females = 0, males = 1. The 6MWT elicited large cardiorespiratory responses with minimal symptoms. The rate of oxygen uptake measured at test-end was associated with the 6MWD (r = 0.802; p < 0.001). These data allow the 6MWD achieved in Canadian adults to be expressed as a percentage of the predicted value and provide researchers and clinicians with values for the expected cardiorespiratory responses in a healthy adult population for the purpose of comparison with patient populations.

Modifying track layout from straight to circular has a modest effect on the 6-min walk distance.

BACKGROUND: The protocol used for the 6-min walk test (6MWT) influences its results. The only study to examine the effect of modifying track layout performed a retrospective analysis and concluded that institutions using continuous tracks yield greater distances than those using straight tracks. Agreement between the distances measured on different tracks could not be examined. We evaluated the effect of modifying track layout on walk distance and examined the agreement and repeatability of distances measured on different tracks. METHODS: In a prospective, randomized, cross-over study, 27 COPD subjects (FEV(1), 38 +/- 14% [mean +/- SD]; 15 men) attended three separate test sessions, completing six 6MWTs. To familiarize all subjects with both tracks, the first two sessions comprised two 6MWTs on either a circular or straight track. During the final session, each subject was tested once on the straight and once on the circular track. RESULTS: The distance walked on the circular track exceeded the straight track by 13 +/- 17 m (p < 0.001). The limit of agreement between tracks was 33 m. Coefficient of repeatability values when the test was completed on different days for the straight and circular tracks were 51 m and 65 m, respectively. CONCLUSIONS: When evaluating changes in 6-min walk distance in groups of patients, track layout should be standardized. However, the effect of modifying track layout on an individual's walking distance is small compared to their daily variability in walk distance. Therefore, standardizing track layout for any given individual may be inconsequential when evaluating the change in distances from tests performed on different days.