From accelerometer output to physical activity intensities in breast cancer patients. Issue 2 (February 2020)

• Record Type: Journal Article
• Authors: Sweegers, Maike G.; Buffart, Laurien M.; Huijsmans, Rosalie J.; Konings, Inge R.; van Zweeden, Annette A.; Brug, Johannes; Chinapaw, Mai J.M.; Altenburg, Teatske M.
• Is Part Of: Journal of science and medicine in sport. Volume 23:Issue 2(2020)
• Page Start: 176
• Page End: 181
• Publication Date: 2020-02
• Subjects: Physical activity -- Accelerometer -- Oncology -- Cut-points -- Physical fitness; Sports sciences -- Periodicals; Sports medicine -- Periodicals; Exercise -- Physiological aspects -- Periodicals; Sports -- physiology -- Periodicals; Sports Medicine -- Periodicals; Sportgeneeskunde; 617.102705
• DOI: 10.1016/j.jsams.2019.09.001
• Languages: English
• ISSNs: 1440-2440

Abstract

Abstract: Objectives: We aimed to investigate accelerometer output corresponding to physical activity intensity cut-points based on percentage of peak oxygen consumption (%VO2 peak) and Metabolic Equivalent of Task (MET) value in women treated for breast cancer. Design: Laboratory study. Methods: Fifty female patients shortly after completion of treatment for breast cancer were included. VO2 peak was determined during a cardiopulmonary exercise test. Subsequently, patients performed ten activities with different intensities while wearing an accelerometer on the right hip and a mobile oxycon to assess oxygen consumption. We studied the relationship between energy expenditure (expressed as %VO2 peak and MET-value) and accelerometer output (in counts per minute (cpm)) with linear regression analyses. We determined accelerometer output corresponding to physical activity intensity cut-points (40% and 60%VO2 peak; 3 and 6 MET) using regression equations. Results: VO2 peak was 22.4 mL/kg/min (SD 5.2) and resting metabolic rate was 3.1 mL/kg/min (SD 0.6). Accelerometer output corresponding to the cut-points for moderate (40% VO2 peak) and vigorous intensity (60% VO2 peak) were 1123 and 1911, respectively. The analyses based on MET-values resulted in accelerometer output of 1189 cpm for the moderate (3 MET) and 2768 cpm for the vigorous intensity cut-point (6 MET). Conclusions: Accelerometer outputs for moderate and vigorous intensity physical activity were lower than commonly used cut-points (i.e. 1952 and 5724 cpm), irrespective of the method used to express energy expenditure (%VO2 peak versus MET-value). Thus, categorizing physical activity intensities based on general-population cut-points, may underestimate physical activity intensities for women treated for breast cancer.