Comparison of Motion Sickness-Induced Cardiorespiratory Responses between Susceptible and Non-susceptible Subjects and the Factors Associated with Symptom Severity

This study aimed to examine the correlations between susceptibility to motion sickness and pulmonary function and aerobic capacity. We supposed that people with different susceptibilities to motion sickness differ in their cardiorespiratory responses. Thirteen healthy young men were recruited. They were asked to complete a motion sickness history questionnaire and were divided into susceptible and non-susceptible groups. A rotary chair was rotated for 10 minutes at 20 rpm to induce motion sickness. After the rotation, Graybiel's diagnostic criteria were used to grade the severity of motion sickness. This study also conducted evaluations of cardiorespiratory responses. Participants underwent a pulmonary function test and an exercise test to evaluate aerobic capacity. A generalized estimating equation was used to analyze the correlation between Graybiel's scores and the pulmonary function and exercise test results. The differences between the two groups were analyzed for the physiological parameters measured. The results indicated higher severities of motion sickness in participants with lower values of maximum voluntary ventilation (MVV). Moreover, the group of susceptible participants demonstrated significantly higher Graybiel's scores and stronger cardiorespiratory responses, significant interaction effects were observed in oxygen consumption, carbon dioxide production (VCO2), ventilation, and respiratory rate. To summarize, MVV is proposed as a reference index for evaluating susceptibility to motion sickness. Severe motion sickness in susceptible participants is suggested to be related to hyperventilation, which causes excessive VCO2.