To validate a new device designed to measure ventilation (V(E)), tidal volume (V(T)), inspiratory time (T(I)), and expiratory time (T(E)) during daily life activities. The anteroposterior displacement of the rib cage and abdomen and the axial displacements of the chest wall and the spine were measured using two pairs of magnetometers. was estimated from these four signals, and was simultaneously measured using a spirometer. A total of 707, 732, and 1,138 breaths were analyzed in sitting, standing, and exercise conditions, respectively. We compared V(E), V(T), T(I), and, T(E) measured by magnetometers (V(E)mag, V(T)mag, T(I)mag, and T(E)mag) with V(E), V(T), T(I), and T(E) measured by a spirometer V(E)spiro, V(T)spiro, T(I)spiro, and T(E)spiro, respectively). For pooled data V(E)mag, V(T)mag, T(I)mag, and T(E)mag were significantly correlated (p < 0.001) with V(E)spiro, V(T)spiro, T(I)spiro, and T(E)spiro in sitting and standing positions and during the walking exercise. The mean differences, between V(E)mag, and V(E)spiro for the group, were 10.44, 10.74, and 12.06% in sitting, standing, and exercise conditions, respectively. These results demonstrate the capacity of this new device to measure V(E) with reasonable accuracy in sitting, standing, and exercise conditions.

The aim of this paper is to validate a new method of energy expenditure (EE) estimation stemming solely from the measurement of rib cage, abdominal and chest wall distances. We set out to prove that the variations of these distances, measured by two pairs of electromagnetic coils, lead to the estimation of the ventilation (VE) and the EE. Eleven subjects were recruited to take part in this study (27.6 ± 5.4 years; 73.7 ± 9.7 kg). Each subject participated in two tests. The objective of Test 1 was to determine the individual and group equations between the VE and EE during light to moderate activities while Test 2 compared the two pairs of electromagnetic coils with the indirect calorimetry so as to estimate EE in upright sitting and standing positions and during walking exercises. During Test 2, we compared EE measured by indirect calorimetry (EE(IC-Val-REF)) with EE estimated by the two pairs of electromagnetic coils through the application of: (1) the individual equation (EE(mag-Val-INDIV)) and (2) the group equation (EE(mag-val-GROUP)). The results show that there is no significant difference between EE(IC-Val-REF) and EE(mag-Val-INDIV) and between EE(IC-Val-REF) and EE(mag-val-GROUP) for each activity. Furthermore, the mean difference seems to show that the estimation of EE is better with the group equation. In conclusion, on the proven basis of this study we are able to validate this new method which permits the estimation of EE from abdominal and rib cage distances. This study also highlights the advantage of using a group equation to the estimate EE.

The aim of this article was to compare 2 portable devices (a heart-rate monitor and an electromagnetic-coil system) that evaluate 2 different physiological parameters--heart rate (HR) and ventilation (VE)--with the objective of estimating energy expenditure (EE). The authors set out to prove that VE is a more pertinent setting than HR to estimate EE during light to moderate activities (sitting and standing at rest and walking at 4, 5, and 6 km/hr). Eleven healthy men were recruited to take part in this study (27.6 ± 5.4 yr, 73.7 ± 9.7 kg). The authors determined the relationships between HR and EE and between VE and EE during light to moderate activities. They compared EE measured by indirect calorimetry (EEREF) with EE estimated by HR monitor (EEHR) and EE estimated by electromagnetic coils (EEMAG) in upright sitting and standing positions and during walking exercises. They compared EEREF with EEHR and EEMAG. The results showed no significant difference between the values of EEREF and EEMAG. However, they showed several significant differences between the values of EEREF and EEHR (for standing at rest and walking at 5 and 6 km/hr). These results showed that the electromagnetic-coil system seems to be more accurate than the HR monitor to estimate EE at rest and during exercise. Taking into consideration these results, it would be interesting to associate the parameters VE and HR to estimate EE. Furthermore, a new version of the electromagnetic-coil device was recently developed and provides the possibility to perform measurement under daily life conditions.