Determining the ventilatory inter-threshold area in individuals with different endurance capacities

There is a general consensus in the literature regarding the existence of two ventilation break points during incremental exercise, i.e., Ventilatory Threshold 1 (VT1) and Ventilatory Threshold 2 (VT2), which mark the boundaries of the aerobic–anaerobic transition. The Inter-Threshold Area (ITA) has been defined as a parameter that connects the ventilatory thresholds. The main aim of the present study was to examine the ITA i.e., the expressed area between VT1 and VT2 for the function: ventilation÷oxygen uptake (VE/VO2 in L2min2) in individuals with various endurance capacities. Six hundred and six men with different levels of endurance completed an incremental exercise test and their ventilatory thresholds were recorded. The ITA is a trapezoid whose area is calculated as the sum of the area of the triangle and rectangle that form it between VT1 and VT2 below the VO2/VE function. The mean ITA for the function VO2–VE was greater in cyclists, as the main representatives for endurance athletes, than the mean corresponding to physical education students, who averaged a lower endurance level (120±34 vs. 86±40L2/min2). The results suggest that the determination of the ITA can reflect metabolic status throughout the aerobic–anaerobic transition during maximal incremental exercise tests.