title: Self-adjustments may account for the contradictory correlations between HRV and motion-sickness severity.
abstract: This study investigates the relationship between heart rate variability (HRV) and the level of motion sickness (MS) induced by simulated tunnel driving. The HRV indices, normalized low frequency (NLF, 0.04-0.15 Hz), normalized high frequency (NHF, 0.15-0.4 Hz), and LF/HF ratio were correlated with the subjectively and continuously rated MS levels of 20 participants. The experimental results showed that for 13 of the subjects, the MS levels positively correlated with the NLF and the LF/HF ratio and negatively correlated with the NHF. The remaining seven subjects had negative correlations between the MS levels and the NLF and the LF/HF ratio and a positive correlation between the MS levels and the NHF. To clarify this contradiction, this study also inspected the effects of subjects' self-adjustments on the correlations between the MS levels and the HRV indices and showed that the variations in the relationship might be attributed to the subjects' self-adjustments, which they used to relieve the discomfort of MS.
authors.affiliation: Brain Research Center, University System of Taiwan, Hsinchu, Taiwan.
authors.forename: Chun-Ling
authors.initials: CL
authors.lastname: Lin
authors.forename: Tzyy-Ping
authors.initials: TP
authors.lastname: Jung
authors.forename: Shang-Wen
authors.initials: SW
authors.lastname: Chuang
authors.forename: Jeng-Ren
authors.initials: JR
authors.lastname: Duann
authors.forename: Chin-Teng
authors.initials: CT
authors.lastname: Lin
authors.forename: Tzai-Wen
authors.initials: TW
authors.lastname: Chiu
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000328:Adult; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D009041:Motion Sickness / Q000503:physiopathology* / Q000523:psychology; D010775:Photic Stimulation / Q000379:methods*; D011597:Psychomotor Performance / Q000502:physiology*; D012720:Severity of Illness Index; D014584:User-Computer Interface; D055815:Young Adult