Incongruent virtual reality cycling exercise demonstrates a role of perceived effort in cardiovascular control

In this study we have used a highly immersive virtual reality (VR) cycling environment where incongruence between virtual hill gradient (created by visual gradient and bike tilt angle) and actual workload (pedalling resistance) can experimentally manipulate perception of exercise effort. This therefore may provide a method to examine the role of effort perception in cardiorespiratory control during exercise. Twelve healthy untrained participants (7 men, age 26 ± 5 years) were studied during five visits. On visit 1 participants underwent cardiopulmonary exercise testing, and during subsequent visits (2-4) participants performed repeated hill climbs at different gradients (of 3%, 6% and 9% in counterbalanced order) with the actual workload 'congruent' with virtual hill gradient. On visit 5 participants completed three incongruent trials with virtual hill gradients of 3%, 6% and 9% but a fixed workload equal to that for the 6% climb (iVR3%, iVR6% and iVR9% trials). Despite no difference in power output, there was a significantly elevated rating of perceived exertion (RPE) and mean arterial blood pressure in iVR9% compared to iVR3% and iVR6%, although this effect decayed over time. There was no effect on any respiratory variable, and no significant reduction in RPE or cardiovascular responses was observed during the iVR3% trial. These data suggest that perception of effort and cardiovascular responses to exercise can be manipulated experimentally via virtual hill gradient (using visual and/or vestibular cues) in a VR environment. This work supports those previously showing the existence of a control mechanism which integrates perception of effort and the cardiovascular response to exercise in humans. KEY POINTS: We aimed to assess whether using a highly immersive virtual reality (VR) cycling environment to create incongruence between perceived effort (virtual hill gradient) and actual effort (pedal resistance) can manipulate cardiorespiratory responses to exercise. At an equivalent power output cycling up a steeper virtual hill produced greater ratings of perceived exertion (RPEs) and blood pressure responses compared to a virtual hill congruent to power output. This work suggests the existence of a control mechanism which integrates perception of exercise effort and the cardiovascular response to exercise, which can be experimentally manipulated by VR.