title: Quantitative assessment of walking time and postural change in patients with COPD using a new triaxial accelerometer system.
abstract: BACKGROUND
  The purpose of this study was to quantify the walking time and frequency of postural changes in daily life in patients with chronic obstructive pulmonary disease (COPD) using a new triaxial accelerometer system.
  
  
  METHODS
  Twenty-six elderly patients with stable COPD (age 76.8 ± 6.2 years; percent forced expiratory volume in one second [%FEV1] 52.9% ± 26.3%) and 20 age-matched elderly subjects (age 73.0 ± 4.2 years; %FEV1 124.0% ± 22.3%) participated in the study. The subjects' time spent walking (slow, fast), standing, sitting, and lying down and the frequency of their postural changes (getting up, standing up) were assessed for 7 consecutive days using an Activity Monitoring And Evaluation System (A-MES™). We analyzed the relationships among walking times, frequency of postural changes, and physiologic factors in both COPD patients and controls.
  
  
  RESULTS
  The COPD patients' total walking time, including slow (<2 km/hour) and fast (≥2 km/hour) walking, and their frequency of standing up were significantly lower than those of the age-matched controls (P < 0.01). The fast walking time in daily life was significantly correlated with the 6-minute walking distance, quadriceps femoris muscle force, and dyspnea (P < 0.01).
  
  
  CONCLUSIONS
  These results suggest that both slow (<2 km/hour) and fast (≥2 km/hour) walking time and frequency of postural changes is significantly decreased in COPD patients compared with healthy elderly subjects. The data also suggest that the COPD patients' different walking times in daily life are significantly correlated with exercise capacity and dyspnea. The 6-minute walking distance had the strongest correlation with fast walking time.
authors.affiliation: Department of Physical Therapy, Akita University Graduate School of Health Sciences, Akita, Japan. mito5958@cna.ne.jp
authors.forename: Atsuyoshi
authors.initials: A
authors.lastname: Kawagoshi
authors.forename: Noritaka
authors.initials: N
authors.lastname: Kiyokawa
authors.forename: Keiyu
authors.initials: K
authors.lastname: Sugawara
authors.forename: Hitomi
authors.initials: H
authors.lastname: Takahashi
authors.forename: Shunichi
authors.initials: S
authors.lastname: Sakata
authors.forename: Saori
authors.initials: S
authors.lastname: Miura
authors.forename: Sachie
authors.initials: S
authors.lastname: Sawamura
authors.forename: Masahiro
authors.initials: M
authors.lastname: Satake
authors.forename: Takanobu
authors.initials: T
authors.lastname: Shioya
mesh_terms: D056044:Actigraphy / Q000295:instrumentation*; D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D004867:Equipment Design; D005080:Exercise Test / Q000295:instrumentation*; D017079:Exercise Tolerance; D005260:Female; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D011187:Posture; D011237:Predictive Value of Tests; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000503:physiopathology; D012720:Severity of Illness Index; D013997:Time Factors; D016138:Walking
keywords: chronic obstructive pulmonary disease; fast walking; frequency of postural changes; slow walking; triaxial accelerometer
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