Energy expenditure during daily activities as measured by two motion sensors in patients with COPD

Background: In patients with chronic obstructive pulmonary disease (COPD), energy expenditure (EE) assessment during the performance of daily activities is not yet studied in depth. The aim of this study was to determine which daily activities are more demanding to patients with COPD and to compare the accuracy of EE estimation given by the pedometer Digiwalker SW701 (DW) and the multisensor SenseWear Armband (SAB).

Methods: Thirty-six patients with COPD (20 men; FEV1 48 ± 15%predicted; BMI 25.7 ± 8 kg/m(2)) were submitted to a modified version of the Glittre ADL-test, which included five activities performed for 1 min each: walking on the level, walking on the level carrying a backpack, walking up/downstairs, rising/sitting in chairs and moving objects in and out of a shelf. During the protocol subjects wore both devices concomitantly, and indirect calorimetry (IC) was simultaneously performed as the criterion method to assess EE.

Results: The most demanding daily activity for individuals with COPD was walking up/downstairs (4.9 ± 1.7 kcal versus 3.7 ± 1.4 to 4.2 ± 1.8 kcal for the other tasks; p < 0.05). EE estimation by the SAB did not show difference in comparison to IC for the sum of the five activities (SAB = 22.7 ± 7 kcal versus IC = 21 ± 8 kcal; p > 0.05), although overestimation was found in activities involving walking. DW showed significant EE underestimation in the sum of the activities (9.6 ± 4.3 kcal; p < 0.05 versus IC) and for each activity.

Conclusion: Walking up/downstairs was the most energy-demanding daily activity for patients with COPD. Furthermore, during daily activities, the multisensor showed adequate overall estimation of energy expenditure, as opposed to the pedometer.