This pilot randomized crossover study will evaluate the acute effects of immersive virtual reality (IVR) on respiratory effort during submaximal exercise in healthy adults. Dyspnea and increased respiratory effort are influenced not only by mechanical and metabolic factors, but also by emotional and central neural inputs. IVR has shown potential to reduce anxiety, promote relaxation, and modulate physiological responses, but its direct effect on respiratory effort has not been adequately studied. Healthy adults will complete two experimental exercise sessions: one session with IVR and one session without IVR, in randomized order. In both conditions, participants will perform a 6-minute constant-load cycling test at a submaximal workload individualized from a prior incremental exercise test. Respiratory effort will be assessed continuously using esophageal pressure monitoring. Additional measurements will include ventilatory variables, perceived dyspnea, acute state anxiety, heart rate, oxygen saturation, and heart rate variability. The primary aim is to determine whether IVR reduces respiratory effort compared with the control condition. This pilot study is intended to provide physiological evidence on the potential role of IVR as a non-pharmacological strategy to modulate respiratory effort and dyspnea, and to inform future research in clinical populations.
Dyspnea is a complex and multidimensional symptom defined as a subjective experience of breathing discomfort that arises from interactions among physiological, psychological, and environmental factors. It is highly prevalent, affecting approximately 10% of the general adult population and up to half of hospitalized patients. The sensation of dyspnea can emerge when there is a mismatch between central respiratory drive and the effective ventilatory response, a condition known as neuromechanical dissociation. In this context, efferent motor signals to the respiratory muscles are accompanied by afferent signals to sensory cortical areas (corollary discharge), which contribute to the conscious perception of respiratory effort and breathing discomfort. Respiratory effort is influenced not only by mechanical and metabolic factors but also by emotional and cognitive processes. Increasing evidence suggests that cortical and limbic networks involved in emotion, attention, and anxiety may modulate the perception of breathing effort. Therefore, interventions capable of modifying emotional or cognitive states may influence respiratory perception and the physiological response to exercise. Immersive virtual reality (IVR) is an emerging technology capable of inducing a strong sense of presence within a simulated environment through visual and auditory immersion. IVR has demonstrated beneficial effects in several clinical contexts, including anxiety reduction, stress modulation, and pain control. By altering sensory input and attentional focus, IVR may also influence physiological responses mediated by central neural mechanisms. However, the potential effect of IVR on respiratory effort and ventilatory control during exercise has not been well characterized. The present study aims to explore the acute physiological effects of IVR on respiratory effort during submaximal exercise in healthy adults. This pilot study uses a randomized crossover design in which participants perform two experimental conditions: exercise with immersive virtual reality and exercise without virtual reality (control condition). Each participant serves as their own control. Participants will complete an initial incremental cardiopulmonary exercise test to determine individual exercise capacity and identify the respiratory compensation point. Based on these results, a constant-load cycling protocol will be prescribed at a submaximal intensity corresponding to a fixed proportion of this threshold. During the experimental sessions, participants will perform a six-minute constant-load cycling test under each condition, separated by at least one week. Respiratory effort will be continuously assessed using esophageal pressure monitoring, allowing calculation of indices such as inspiratory effort and pressure-time product. Additional physiological and perceptual variables will also be collected, including ventilatory parameters, tidal volume, respiratory rate, inspiratory time, heart rate, oxygen saturation, heart rate variability, perceived dyspnea using the Borg scale, and acute state anxiety measured through a validated questionnaire. The primary objective of this pilot study is to evaluate whether immersive virtual reality reduces respiratory effort during submaximal exercise compared with the control condition. Secondary objectives include exploring the effects of IVR on ventilatory responses, perceived dyspnea, and anxiety. The findings are intended to provide preliminary physiological evidence regarding the potential role of immersive virtual reality as a non-pharmacological strategy to modulate respiratory perception and respiratory effort, and to inform the design of future studies in clinical populations experiencing dyspnea.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
NONE
Enrollment
10
Participants are exposed to immersive virtual reality using a head-mounted display during a constant-load submaximal cycling exercise test. The virtual environment provides visual and auditory immersion designed to induce a sense of presence and relaxation. Exercise intensity is individualized based on a prior incremental cardiopulmonary exercise test. The intervention is intended to evaluate the acute effects of immersive virtual reality on respiratory effort, ventilatory responses, and perceived dyspnea during exercise.
Escuela de Ciencias de la Salud UC. Departamento de Kinesiología.
Santiago, Santiago Metropolitan, Chile
RECRUITINGEsophageal pressure swing (ΔPes)
Esophageal pressure swing (ΔPes), defined as the absolute difference between end-expiratory and end-inspiratory esophageal pressure, measured using an esophageal balloon catheter.
Time frame: At baseline (2 minutes before exercise), and in both arms (control and IVR) during the final 2 minutes of the 6-minute constant-load submaximal exercise test, and during the 2-minute post-exercise recovery period.
Pressure-time product per minute (PTPmin)
Pressure-time product per minute (PTPmin), expressed as cmH₂O·s/min, measured using an esophageal balloon catheter as an index of global inspiratory effort.
Time frame: At baseline (2 minutes before exercise), and in both arms (control and IVR) during the final 2 minutes of the 6-minute constant-load submaximal exercise test, and during the 2-minute post-exercise recovery period.
Modified Borg dyspnea score (0-10)
Dyspnea intensity will be assessed using the modified Borg scale, a self-reported numerical rating scale ranging from 0 to 10, where 0 indicates no breathing discomfort and 10 indicates maximal breathing discomfor
Time frame: At baseline (2 minutes before exercise), and in both arms (control and IVR) during the final 2 minutes of the 6-minute constant-load submaximal exercise test, and during the 2-minute post-exercise recovery period.
Early inspiratory esophageal pressure (Pes at 100 ms)
Early inspiratory esophageal pressure measured 100 ms after the onset of inspiratory effort using the esophageal pressure signal obtained from an esophageal balloon catheter. This parameter is used as an index of central respiratory drive.
Time frame: At baseline (2 minutes before exercise), and in both arms (control and IVR) during the final 2 minutes of the 6-minute constant-load submaximal exercise test, and during the 2-minute post-exercise recovery period.
Peak inspiratory flow (PIF)
Peak inspiratory flow will be measured breath-by-breath during exercise using a flow sensor and mouthpiece connected to a pneumotachograph. The highest inspiratory flow generated during each respiratory cycle will be recorded and analyzed.
Time frame: At baseline (2 minutes before exercise), and in both arms (control and IVR) during the final 2 minutes of the 6-minute constant-load submaximal exercise test, and during the 2-minute post-exercise recovery period.
Peak expiratory flow (PEF)
Peak expiratory flow will be measured breath-by-breath during exercise using a mouthpiece with nose clip and a flow sensor connected to a pneumotachograph. The highest expiratory flow generated during each respiratory cycle will be recorded and analyzed.
Time frame: At baseline (2 minutes before exercise), and in both arms (control and IVR) during the final 2 minutes of the 6-minute constant-load submaximal exercise test, and during the 2-minute post-exercise recovery period.
Inspiratory time (Ti)
Inspiratory time will be measured breath-by-breath from the airflow signal obtained using a mouthpiece with nose clip and a flow sensor connected to a pneumotachograph. Inspiratory time is defined as the duration from the onset of inspiratory airflow to the end of inspiration for each respiratory cycle.
Time frame: At baseline (2 minutes before exercise), and in both arms (control and IVR) during the final 2 minutes of the 6-minute constant-load submaximal exercise test, and during the 2-minute post-exercise recovery period.
Inspiratory duty cycle (Ti/Ttot)
Inspiratory duty cycle will be calculated breath-by-breath from the airflow signal obtained using a mouthpiece with nose clip and a flow sensor connected to a pneumotachograph. Ti/Ttot represents the ratio between inspiratory time (Ti) and total respiratory cycle time (Ttot), providing an index of the fraction of the respiratory cycle spent in inspiration.
Time frame: At baseline (2 minutes before exercise), and in both arms (control and IVR) during the final 2 minutes of the 6-minute constant-load submaximal exercise test, and during the 2-minute post-exercise recovery period.
Respiratory Rate (RR)
Respiratory rate will be measured breath-by-breath from the airflow signal obtained using a mouthpiece with nose clip and a flow sensor connected to a pneumotachograph. Respiratory rate will be calculated as the number of respiratory cycles per minute derived from the airflow signal.
Time frame: At baseline (2 minutes before exercise), and in both arms (control and IVR) during the final 2 minutes of the 6-minute constant-load submaximal exercise test, and during the 2-minute post-exercise recovery period.
Expiratory time (Te)
Expiratory time will be measured breath-by-breath from the airflow signal obtained using a mouthpiece with nose clip and a flow sensor connected to a pneumotachograph. Expiratory time is defined as the duration from the onset of expiratory airflow to the end of expiration for each respiratory cycle.
Time frame: At baseline (2 minutes before exercise), and in both arms (control and IVR) during the final 2 minutes of the 6-minute constant-load submaximal exercise test, and during the 2-minute post-exercise recovery period.
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