Autonomic Nervous System Responses to Whole-Body Vibration and Mental Workload: A Pilot Study

Hamed Jalilian, Zahra Zamanian, Omid Gorjizadeh, Shahrzad Riaei, Mohammad Reza Monazzam, Mohammad Abdoli-Eramaki

Abstract


Background: Whole-body vibration (WBV) and mental workload (MWL) are common stressors among drivers who attempt to control numerous variables while driving a car, bus, or train.

Objective: To examine the individual and combined effects of the WBV and MWL on the autonomic nervous system.

Methods: ECG of 24 healthy male students was recorded using NeXus-4 while performing two difficulty levels of a computerized dual task and when they were exposing to WBV (intensity 0.5 m/s2; frequency 3–20 Hz). Each condition was examined for 5 min individually and combined. Inter-beat intervals were extracted from ECG records. The time-domain and frequency-domain heart rate variability parameters were then extracted from the inter-beat intervals data.

Results: A significant (p=0.008) increase was observed in the mean RR interval while the participants were exposed to WBV; there was a significant (p=0.02) reduction in the mean RR interval while the participants were performing the MWL. WBV (p=0.02) and MWL significantly (p<0.001) increased the standard deviation of normal-to-normal intervals with a moderate-to-large effect size. All active periods increased the low-frequency component and low-frequency/high-frequency ratio. However, only the WBV significantly increased the highfrequency component. A significant (p=0.01) interaction was observed between the WBV and MWL on low-frequency component and low-frequency/high-frequency ratio.

Conclusion: Exposure to WBV and MWL can dysregulate the autonomic nervous system. WBV stimulates both sympathetic and parasympathetic nervous system; MWL largely affects sympathetic nervous system. Both variables imbalance the sympatho-vagal control as well.


Keywords


Autonomic nervous system; Vibration; Mental processes; Workload; Heart rate



doi: 10.15171/ijoem.2019.1688


 pISSN: 2008-6520
 eISSN: 2008-6814

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