2018 Volume 14 Issue 1 Pages 17-25
This study investigated the influence of mental stress on trunk vibration while standing and on autonomic nerve function.
The study included 16 healthy male volunteers. As a mental workload, participants performed a Stroop task (ST) consisting of reading aloud groups of letters in which the meaning of the letters and their color did not correspond. Monochrome letter groups were read aloud as a control task. The evaluation parameters included subjective evaluation of the task using the visual analog scale (VAS), vibration at two locations in the back (T1-2 and T11-12), and the earlobe pulse wave. Frequency analysis of the pulse wave was performed, and the low frequency component was divided by the high frequency component (LF/HF ratio) to evaluate autonomic nerve function.
Psychological stress and fatigue VAS scores were significantly higher after the ST compared to the control task (P<0.05). Vibration at T1-2 and the LF/HF ratio during the ST significantly increased compared to before and after the ST (P<0.01). The increase in upper trunk vibration and LF/HF ratio with mental stress suggests that mental stress increases muscle tone in association with increased sympathetic nerve activity.
