Research Study Abstract

Validity of Six Activity Monitors in Chronic Obstructive Pulmonary Disease: A Comparison with Indirect Calorimetry

  • Added on June 20, 2012

Reduced physical activity is an important feature of Chronic Obstructive Pulmonary Disease (COPD). Various activity monitors are available but their validity is poorly established. The aim was to evaluate the validity of six monitors in patients with COPD. We hypothesized triaxial monitors to be more valid compared to uniaxial monitors. Thirty-nine patients (age 68±7 years, FEV1 54±18% predicted) performed a one-hour standardized activity protocol. Patients wore 6 monitors (Kenz Lifecorder (Kenz), Actiwatch, RT3, Actigraph GT3X (Actigraph), Dynaport MiniMod (MiniMod), and SenseWear Armband (SenseWear)) as well as a portable metabolic system (Oxycon Mobile). Validity was evaluated by correlation analysis between indirect calorimetry (VO2) and the monitor outputs: Metabolic Equivalent of Task [METs] (SenseWear, MiniMod), activity counts (Actiwatch), vector magnitude units (Actigraph, RT3) and arbitrary units (Kenz) over the whole protocol and slow versus fast walking. Minute-by-minute correlations were highest for the MiniMod (r = 0.82), Actigraph (r = 0.79), SenseWear (r = 0.73) and RT3 (r = 0.73). Over the whole protocol, the mean correlations were best for the SenseWear (r = 0.76), Kenz (r = 0.52), Actigraph (r = 0.49) and MiniMod (r = 0.45). The MiniMod (r = 0.94) and Actigraph (r = 0.88) performed better in detecting different walking speeds. The Dynaport MiniMod, Actigraph GT3X and SenseWear Armband (all triaxial monitors) are the most valid monitors during standardized physical activities. The Dynaport MiniMod and Actigraph GT3X discriminate best between different walking speeds. Link to Abstract:


  • Hans Van Remoortel 1
  • Yogini Raste 2
  • Zafeiris Louvaris 3
  • Santiago Giavedoni 4
  • Chris Burtin 1
  • Daniel Langer 1
  • Frederick Wilson 5
  • Roberto Rabinovich 4
  • Ioannis Vogiatzis 3
  • Nicholas S. Hopkinson 2
  • Thierry Troosters 1
  • on behalf of PROactive consortium


  • 1

    Faculty of Kinesiology and Rehabilitation Sciences, Department of Rehabilitation Sciences, Katholieke Universiteit Leuven, and Respiratory Division, UZ Gasthuisberg, Leuven, Belgium

  • 2

    NIHR Respiratory Biomedical Research Unit at Royal Brompton and Harefield NHS Foundation Trust and Imperial College, London, United Kingdom

  • 3

    Thorax Foundation, Research Centre of Intensive and Emergency Thoracic Medicine, and Department of Physical Education and Sports Sciences, National and Kapodistrian University of Athens, Athens, Greece

  • 4

    ELEGI Colt Laboratory, Centre for Inflammation Research, University of Edinburgh, Edinburgh, Scotland, United Kingdom

  • 5

    Precision Medicine, Pfizer Worldwide Research and Development, Sandwich, Kent, United Kingdom




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