A comparison between ventilation and heart rate as indicator of oxygen uptake during different intensities of exercise

The aim of this study is to compare the relation between ventilation (V(E)) and oxygen uptake (VO(2)) [VO(2)= f (V(E))] and between heart rate (HR) and VO(2) [VO(2)= f (HR)]. Each one of the subjects performed three types of activities of different intensities (walking without load, walking with load and intermittent work). VO(2), V(E), and HR were measured continuously by using indirect calorimetry and an electrocardiogram. Linear regressions and coefficients of determination (r(2)) were calculated to compare the relation VO(2) = f (V(E)) and VO(2) = f (HR) for two different regroupings: by session duration (r(session)(2)) and by subject (r(subject)(2)). Results showed that r(session)(2) of the relation VO(2) = f (V(E)) were significantly higher than those of the relation VO(2) = f (HR) for steady state activities (walking with or without load during 3 or 6 min, p < 0.01) and for activities without oxygen consumption steady state (walking with or without load during 1 min, p < 0.01 and intermittent work, p < 0.05). V(E) is more strongly correlated with VO(2) than with HR. This is a very promising approach to develop a new method to estimate energy expenditure.