Lack of validity of free-living physical activity energy expenditure estimated from ActiGraph equations in severely obese women: A doubly labelled water study

ABSTRACT

The current study aimed to investigate the validity of three ActiGraph predictive equations that are available to estimate free-living physical activity energy expenditure (PAEE) in women with severe obesity. The study included 20 women with class III obesity (age: 22–38 years). During 14 days of free-living conditions, total energy expenditure was measured using the doubly labelled water method; in addition, participants wore a triaxial accelerometer (model GT3X+) on the hip. The resting metabolic rate was measured by indirect calorimetry. At group level, the Freedson VM3 Combination was found to be more precise (bias = −61 kcal/day) than the Williams Work-Energy (bias = −283 kcal/day) and the Freedson Combination equations (bias = −186 kcal/day) for estimating PAEE. However, the three predictive equations had a wider limit of agreement (Williams Work-Energy [258, −824 kcal/day], Freedson Combination equations [324, −697 kcal/day] and Freedson VM3 Combination [424, −546 kcal/day]), indicating great uncertainty of the estimate. In conclusion, a wide variation was observed in the performance of different ActiGraph equations in estimating free-living PAEE among women with class III obesity. Therefore, our data do not support the use of these equations, and more studies are needed to improve predictive performance in free-living conditions.

KEYWORDS:

• Accelerometery
• obesity
• energetic cost
• agreement

Acknowledgments

The authors would like to thank Dr. Dale Schoeller for his technical assistance with DLW analysis, critical reading and helpful comments on this manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was funded by the Fundação de Amparo à Pesquisa do Estado de São Paulo – (FAPESP) under grant number 13/04420-4. Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) supported through scholarships ─ Financial Code 001