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

Abstract

The aim of this study is to compare the relation between ventilation (VE) and oxygen uptake (VO2) [VO2=ƒ(VE)] and between heart rate (HR) and VO2 [VO2=ƒ(HR)]. Each one of the subjects performed three types of activities of different intensities (walking without load, walking with load and intermittent work). VO2, VE, 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 VO2 =ƒ(VE) and VO2 =ƒ(HR) for two different regroupings: by session duration (r(2) session) and by subject (r(2) subject). Results showed that r(2) session of the relation VO2 =ƒ(VE) were significantly higher than those of the relation VO2 =ƒ(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). VE is more strongly correlated with VO2 than with HR. This is a very promising approach to develop a new method to estimate energy expenditure. Key pointsVentilation is more strongly correlated with oxygen uptake than heart rate during physical activities of different intensities.This study shows the interest to looking for ventilation to estimate energy expenditure.This study is a promising approach to develop a new method to estimate energy expenditureAn interesting perspective could be to develop a light and portable device to measure ventilation based on the coupling of four magnetometers.

Keywords: Physical activities; light to moderate intensities; non-steady state activities.; steady state activities.

Figure 1.

Description of the four days (D1, D2, D3 and D4) and details of the activity “walking with load” (example of the experimental protocol of the subject n°4).

Figure 2.

Details of the experimental protocol: walking with and without load (68 walks).

Figure 3.

Linear regressions (r², p and SEE) from the relations VO₂= f (V_E) and VO₂= f (HR) on the pooled data of the group 1 (walking with or without load during 3 min, 20 walks), the group 2 (walking with or without load during 6 min, 26 walks), the group 3 (walking with or without load during 1 min, 22 walks) and the group 4 (intermittent work, 12 exercises).