Accumulated oxygen deficit during ramp exercise

This study aimed to compare oxygen deficit during exhaustive ramp exercise (OD ramp and OD lag) with maximal oxygen deficit during a high-intensity constant-power test (MAOD). OD ramp was estimated from the difference between oxygen demand and actual oxygen uptake. OD lag was estimated using a simple equation assuming a linear increase in oxygen uptake lagging behind metabolic requirement. After a first test providing estimation of P peak, 12 healthy males did two 15 W.min(-1) and two 30 W.min(-1) ramp tests to evaluate in duplicate OD ramp and OD lag and an exhaustive exercise at 105% of P peak to evaluate MAOD. OD ramp from the 15 W.min(-1) tests (1.50 +/- 1.83 and 2.60 +/- 2.12 l) and from the 30 W.min(-1) tests (2.41 +/- 1.00 and 2.72 +/- 1.23 l) did not differ from MAOD (2.33 +/- 0.50 l). Contrary to OD lag estimated from the 15 W.min(-1) tests (2.27 +/- 0.30 and 2.31 +/- 0.31 l), OD lag from the 30 W.min(-1) tests (2.51 +/- 0.34 and 2.52 +/- 0.36 l) was significantly greater than MAOD (p < 0.05). The conclusion is that the oxygen deficit would accumulate progressively during a ramp test until attaining the maximal oxygen deficit. This measurement would not however give reliable index of an individual subject due to the elevated test-retest variability.