Lung volume estimation for thoracic respiration via chest size deviation measurement

Individual thermal stress of people in physical training has not been evaluated quantitatively in real time. The main limitations in evaluating individual thermal stress are the difficulties in measuring individual thermal parameters, clothing insulation, and metabolic rate. In this study, we aimed to overcome these limitations with metabolic rate measurement. For calculating metabolic rate in real time without breath gas analysis, we proposed a derivation method from oxygen consumption and lung volume. We found that the deviation of chest size is proportional to the change of lung volume in each person, and the coefficient of determination was greater than 0.90.