A test to establish maximum O2uptake despite no plateau in the O2uptake response to ramp incremental exercise

Abstract

The O 2 uptake (V̇o 2) response to ramp incremental (RI) exercise does not consistently demonstrate plateau-like behavior at the limit of tolerance, and hence the requirements for a maximum V̇o 2 commonly are not met, despite apparent maximum effort. We sought to determine whether an appended step exercise (SE) test at a work rate greater than that achieved in a preceding ramp test would establish the plateau criterion. Seven healthy male adults performed RI cycle ergometry (20 W/min) to the limit of tolerance, followed by 5-min recovery (20 W) and then an SE test at 105% (RISE-105) of the final work rate (WR peak) achieved during RI. Five of these subjects also performed an RI test followed by SE at 95% WR peak(RISE-95). V̇o 2 was measured breath by breath using a turbine and mass spectrometer. The average of the final 15 s of RI or SE was used to establish respective V̇o 2 peaks. When V̇o 2 peak was approached, a constant V̇o 2 value (e.g., a plateau) was not discernable during any RI or SE component of the tests. Although the WR peak[mean (SD)] was higher during the SE portion [359 W (SD 31)] than during the RI portion [341 W (SD 29)] of the RISE-105, the peak V̇o 2 was not different [SE, 4.30 l/min (SD 0.51); RI, 4.33 l/min (SD 0.52); P = 0.49; n = 7]. Similarly, in the RISE-95 test, WR peak was 310 W (SD 31) for the SE portion and 326 W (SD 32) for the RI portion, yet the peak V̇o 2 values were not different [SE, 4.12 l/min (SD 0.53); RI, 4.11 l/min (SD 0.48); P = 0.78; n = 5]. The lack of notable difference between the V̇o 2 peaks established at different WR peak values in our RISE protocols provides the plateau criterion for verification of maximum V̇o 2 in a single test session, even when the data response profiles do not themselves evidence a plateau.