Author:

Keywords:

objective monitoring, validity, assessment, energy expenditure, physical activity

Abstract:

Introduction: When conducting epidemiological and interventional studies, it is important to select the appropriate assessment tool. Multi-sensor activity monitors such as the SenseWear Pro3 Armband (SWA) have been shown a valid and practical tool in measuring the energy expenditure (EE) of daily living activities. Recent validation studies however have reported inconclusive results for the measurement of vigorous intensity activities and found significant errors in predicting EE of activities of very vigorous intensity. Therefore the purpose of this study is to assess the accuracy of the SWA in measuring EE at different intensity levels. Methods: Data was obtained from 44 students (24 male and 20 female), averaged 21.1 (±1.4) yr of age, performing an incremental running test. The activity protocol included walking activities of moderate (3 - 6 METs) intensity and running activities of vigorous (6 – 9 METs) and very vigorous intensity (> 9 METs). By means of a paired t-test, the differences in EE estimated from the SWA with the EE measured from the Indirect Calorimetry (IC), used as the criterion measure, were analyzed. Agreement between the two methods was assessed by the Bland and Altman method and by means of correlation coefficients. Results: The SWA underestimated EE for vigorous (-1.36 ± 1.17 kcal/min) and very vigorous activities (-5.80 ± 3.71 kcal/min). No significant difference in EE was found for moderate intensity activities (p=0.586). The Bland-Altman analysis indicates that the 95% limits of agreement between the two methods ranged from -1.76 kcal/min to 1.85 kcal/min for moderate intensity, from -3.66 kcal/min to 0.94 kcal/min for vigorous intensity and from -13.06 kcal/min to 1.47 kcal/min for very vigorous intensity. The two methods do not consistently provide similar measures for very vigorous intensity activities because there is a level of disagreement that includes an underestimation of up to 13.06 kcal/min. EE measured by the SWA and IC were significantly correlated for moderate (r = 0.64, p < 0.0001), vigorous (r = 0.65, p < 0.0001) and very vigorous intensity (r = 0.69, p < 0.0001) activities. Conclusions: According to our results, the SWA is a valid tool in estimating EE of moderate intensity activities and can be used in daily life. Since exceeding this intensity results in a significant underestimation of EE, the SWA cannot be used for predicting the EE of vigorous to very vigorous intensities such as running. In future the EE equation needs to be adjusted to give an accurate estimate of EE for high intensity exercises.