Virtual training leads to real acute physical, cognitive, and neural benefits on healthy adults: study protocol for a randomized controlled trial

BACKGROUND: Keeping a certain level of physical activity has beneficial effects on the body itself but also, surprisingly, on cognition: specifically, physical high-intensity intermittent aerobic exercise (HIE) can show improvement on cognitive executive functions. Although, in some cases performing strength or aerobic training is problematic or not feasible. Immersive virtual reality (IVR) can induce the illusory feeling of ownership and agency over a moving virtual body, therefore showing comparable physiological reactions: for example, if an individual is sitting on a chair but his virtual body climbs a hill, the individual’s heart rate increases coherently, as if he is actually walking. In this study, we investigate whether this same illusion can show beneficial consequences on the body as well as on executive functions (using the color-word matching Stroop task) and on its neural substrates (using functional near-infrared spectroscopy [fNIRS]). METHODS: In a cross-over randomized controlled trial, 30 healthy young adults will experience HIE training in IVR (i.e. the virtual body will perform eight sets of 30 s of running followed by 30 s of slow walking, while the participant is completely still) according to two random-ordered conditions: during the experimental condition, the virtual body is displayed in first-person perspective (1PP), while in the control condition, the virtual body is displayed in third-person perspective (3PP). To confirm that individuals have the illusion of ownership and agency over the virtual body in 1PP (and not in 3PP), we will record the heart rate, in addition to subjective questionnaires. Before and after every IVR sessions (one week apart), we will measure cortical hemodynamic changes in the participants’ prefrontal cortex using the fNIRS device during the Stroop task’s execution. DISCUSSION: From a theoretical perspective, we could prove that the sense of body ownership and agency can modulate physical and cognitive parameters, even in the absence of actual movements; from a clinical perspective, these results could be useful to train cognition and body simultaneously, in a completely safe environment. TRIAL REGISTRATION: University Hospital Medical Information Network Clinical Trial Registry, UMIN000034255. Registered on 1 October 2018. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13063-019-3591-1) contains supplementary material, which is available to authorized users.