The potential to change pacing and performance during 4000m cycling time trials using hyperoxia and inspired gas-content deception

The aim of this study was to determine if a series of trials manipulating FiO₂ content and belief (through deception) might change pacing and performance during 4000m cycling time trials.

At a glance:

• Hyperoxic and oxygen deception time trials have the potential to build belief and improve performance in subsequent normoxic trials or competitive events.
• The order of hyperoxic and deception time trials may encourage athletes to deviate from their routine pacing template.
• Future studies manipulating the FiO₂ should consider the effects trial order and participants’ knowledge of the FiO₂ may have on exercise regulation.

Purpose:
To determine if a series of trials with fraction of inspired oxygen (FiO₂) content deception could improve 4000-m cycling time-trial (TT) performance.

Methods:
A total of 15 trained male cyclists (mean [SD] body mass 74.2 [8.0] kg, peak oxygen uptake 62 [6] mL·kg^-1·min^-1) completed six 4000-m cycling TTs in a semirandomized order. After a familiarization TT, cyclists were informed in 2 initial trials they were inspiring normoxic air (NORM, FiO₂ 0.21); however, in 1 trial (deception condition), they inspired hyperoxic air (NORM-DEC, FiO₂ 0.36). During 2 subsequent TTs, cyclists were informed they were inspiring hyperoxic air (HYPER, FiO₂ 0.36), but in 1 trial, normoxic air was inspired (HYPER-DEC). In the final TT (NORM- 1NFORM), the deception was revealed and cyclists were asked to reproduce their best TT performance while inspiring normoxic air.

Results:
Greater power output and faster performances occurred when cyclists inspired hyperoxic air in both truthful (HYPER) and deceptive (NORM-DEC) trials than NORM (P< .001). However, performance only improved in NORM-INFORM (377 W; 95% confidence interval [CI] 325—429) vs NORM (352 W; 95% Cl 299-104; P< .001) when participants (n = 4) completed the trials in the following order: NORM-DEC, NORM, HYPER-DEC, HYPER.

Conclusions:
Cycling performance improved with acute exposure to hyperoxia. Mechanisms for the improvement were likely physiological; however, improvement in a deception trial suggests an additional placebo effect. Finally, a particular sequence of oxygen deception trials may have built psychophysiological belief in cyclists such that performance improved in a subsequent normoxic trial.

Full reference and abstract:
Davies, M., Clark, B., Lewis, L., Gore, C., Welvaert, M., Thompson, K.G. (2019) The potential to change pacing and performance during 4000-m cycling time trials using hyperoxia and inspired gas-content deception. International Journal of Sport Physiology and Performance, 2019, 14(7):949-957.