Relationship Between Heart Rate, Oxygen Consumption, and Energy Expenditure in Futsal

The primary aim of this study was to compare the measured oxygen consumption (Measured-VO(2)) in a simulated futsal game (S-Game) with the estimated oxygen consumption (Estimated-VO(2)) through a regression equation between heart rate (HR) and oxygen consumption (VO(2)) (HR-VO(2)) in treadmill running, and a secondary aim was to calculate the total energy expenditure (EE) in S-Game. Ten professional players (22.20 ± 3.22 years) were evaluated. HR-VO(2) was determined individually in the continuous test on the treadmill (Cont(Test)). The Measured-VO(2) in S-Game was compared with the Estimated-VO(2) in the Cont(Test). Alactic and lactic pathways were estimated by VO(2). The Estimated-VO(2) presented no statistically significant difference with the Measured-VO(2), using the paired t-test (p = 0.38). However, the correlation between Estimated- and Measured-VO(2) was very weak (r = −0.05), and it presented poor agreement (concordance correlation coefficient = −0.04). In addition, a Bland–Altman plot presented bias of −2.8 ml/kg/min and individual difference as large as 19 ml/kg/min. The HR-VO(2) determined by the Cont(Test) was not a good individual predictor of VO(2). The high intensity and intermittent nature of the futsal game possibly caused dissociation in the HR-VO(2) relationship. Cont(Test) is not recommended for estimating VO(2) and calculating individual EE in the futsal game. This is recommended only for the group mean. The total EE in S-Game was 13.10 ± 1.25 kcal.min(−1) (10.81 ± 1.57 metabolic equivalents). The contributions from the metabolic pathways were as follows: aerobic (93%), alactic (5%), and lactic (2%).