<b>Characterization of the heart rate curve during a maximum incremental test on a treadmill</b>. DOI: 10.5007/1980-0037.2011v13n4p285

Abstract

The objective of this study was to analyze the heart rate (HR) profile plotted against incremental workloads (IWL) during a treadmill test using three mathematical models [linear, linear with 2 segments (Lin2), and sigmoidal], and to determine the best model for the identification of the HR threshold that could be used as a predictor of ventilatory thresholds (VT1 and VT2). Twenty-two men underwent a treadmill incremental test (retest group: n=12) at an initial speed of 5.5 km.h-1, with increments of 0.5 km.h-1 at 1-min intervals until exhaustion. HR and gas exchange were continuously measured and subsequently converted to 5-s and 20-s averages, respectively. The best model was chosen based on residual sum of squares and mean square error. The HR/IWL ratio was better fitted with the Lin2 model in the test and retest groups (p0.05). During a treadmill incremental test, the HR/IWL ratio seems to be better fitted with a Lin2 model, which permits to determine the HR threshold that coincides with VT1.

Keywords

• Boltzmann sigmoidal model
• Ergometry
• Exercise test
• Physical exertion
• Heart rate.