Influence of cycling history on the ventilatory response to cycle-ergometry in humans: a role for respiratory memory?

The ventilatory (V' E) mechanisms subserving stability of alveolar and arterial PCO2 (PACO2, PaCO2) during moderate exercise (< lactate threshold, thetaL) remain controversial. As long-term modulation has been argued to be an important contributor to this control process, we proposed that subjects with no experience of cycling (NEx) might provide insight into this issue. With no exercise familiarization, 9 sedentary NEx subjects and 9 age-, sex-, and activity-matched controls (C) who had cycled regularly for recreational purposes since childhood completed a square-wave (6-min stage) cycle-ergometry test: 10 W-WR1-WR2-WR1-10 W; WR1 range 25-45 W, WR2 range 50-90 W. WRs were subsequently confirmed to <thetaL. The NEx V'E-V'CO2 slope, V'E-intercept, mean PACO2 and estimated alveolar ventilation were not different from C. In conclusion, these findings provide no support for, and possibly support for no, V'E control during moderate exercise being modulated by influences related to long-term exercise history.