Rationale The SenseWear armband (SAB) is designed to measure energy expenditure (EE). In people with chronic obstructive pulmonary disease (COPD), EE estimated using the SAB (EE SAB ) is a popular outcome measure. However, a detailed analysis of the measurement properties of the SAB in COPD is lacking. Objective To examine the sensitivity of EE SAB , agreement between EE SAB and EE measured via indirect calorimetry (EE IC ), and its repeatability in COPD. Methods 26 people with COPD (forced expiratory volume in 1 s (FEV 1 )¼49618% predicted; 15 males) spent 6 min in five standardised tasks that comprised supine, sitting, standing and two walking speeds. A subgroup (n¼12) walked using a rollator. Throughout each task, measurements of EE SAB and EE IC were collected. The protocol was repeated on a second day. Results EE SAB increased between standing and slow walking (2.4, metabolic equivalents (METs) 95% CI 2.2 to 2.7) as well as slow and fast walking (0.5 METs, 95% CI 0.3 to 0.7). Considering all tasks together, the difference between EE SAB and EE IC was À0.2 METs (p¼0.21) with a limit of agreement of 1.3 METs. The difference between days in EE SAB was 0.0 METs with a coefficient of repeatability of 0.4 METs. Rollator use increased the variability in EE SAB , compromising its repeatability and agreement with EE IC . Conclusions EE SAB was sensitive to small but important changes. There was fair agreement between EE SAB and EE IC , and measurements of EE SAB were repeatable. These observations suggest that the SAB is useful for the evaluation of EE in patients with COPD who walk without a rollator.

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Summary at a glance:In patients with moderate COPD, the six-minute walk test, incremental shuttle walk test and endurance shuttle walk test elicited a similar peak rate of oxygen uptake and heart rate response as a ramp cycle ergometry test, demonstrating that both self-and externally-paced field tests progress to high intensities. 4 ABSTRACTBackground and objective: Field and laboratory-based tests are used to measure exercise

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.

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