Energy expenditure in obese children : evaluation of a new multisensor device

Purpose Overweight and obesity are increasing among Italian children, particularly due to sedentary lifestyle. The evaluation of daily energy expenditure (EE) is therefore relevant to assess the level of physical activity in subjects at risk. Portable devices could improve the free-living EE monitoring, provided they are properly calibrated and validated. The present study aimed at evaluating a new multisensor wrist monitor (WM) (E3®, Empatica srl, Italy) in EE assessment in obese children and adolescents. Methods Twenty-eight participants (15 males; age 13 ± 2 years; mean ± SD) were enrolled. Nineteen subjects were obese (body mass index (BMI) >95th percentile for age and sex). Subjects were tested (1) while sitting (SIT), and during (2) walking at comfortable speed (SS) and (3) at faster speed (FS). EE was assessed in each condition by both indirect calorimetry (IC, by oxygen consumption measurement) and multisensor (accelerometry, heart rate, skin galvanic reaction, temperature) methods. Results EE measured during SIT, SS and FS was 1.48 ± 0.31, 4.25 ± 0.68 and 5.64 ± 0.92 METs with IC and 1.19 ± 0.11, 3.82 ± 0.77 and 5.17 ± 0.81 METs with WM, respectively. A significant difference (P < 0.01) between measurement methods in SS and FS condition (pooled data) disappeared in obese individual subgroup. The linear regression coefficient between EEs obtained by the two methods was 0.79 (P < 0.05), and the Bland–Altman plot showed a proportional bias. Conclusions EE estimated by the multisensor wrist monitor highly correlated with the values obtained by IC, particularly in the subgroup of obese children and adolescents, suggesting that it can be used to monitor physical activity in this specific population.