Journal of Nature and Science of Medicine · Published 2026-06-08 · DOI 10.4103/jnsm.jnsm_83_25
Mayowa Jeremiah Adeniyi, Ayoola Awosika
Objective: Facial expressions exert psychophysiologic effects that extend beyond emotional communication, influencing orthostatic changes, autonomic responses, and heart rate variability (HRV). Emerging evidence suggests that proprioceptive feedback from facial musculature can modulate central autonomic networks, yet the precise mechanisms remain underexplored. Electroencephalogram (EEG) recordings demonstrate shifts in cortical oscillations with varying facial expressions, but their relationship with cardiovascular adjustments during postural transitions is poorly characterized. This knowledge gap limits our understanding of how embodied emotion contributes to stress adaptation, cerebral autoregulation, and syncope susceptibility. This study investigated the effect of intermittent voluntary facial expressions on orthostatic EEG. Materials and Methods: Forty apparently healthy young males, averaging 19.6 years, who satisfied the inclusion criteria were selected for the study. An electroencephalogram was recorded using Powerlab 26T as previously reported, and participants stood upright for 20 min. Participants performed each of the facial expressions (frown, smile, and laugh) once every 10 s (using stop watch) for a 20 min period. Results: Intermittent voluntary expressions of frown, smile, and laughter during orthostasis significantly increased alpha/beta ratio when compared to baseline, respectively (P = 0.0001, 0.008, and 0.0001). Voluntary expression of a smile during orthostasis was also found to be associated with a significantly lower alpha/beta ratio (P = 0.039) when compared to laughter during orthostasis. Conclusion: The finding of the study indicates the relative advantage of intermittent smile during prolonged standing over other voluntary facial expressions in healthy individuals. Positive expressions, such as smiling, may buffer orthostatic intolerance by enhancing parasympathetic tone, while negative expressions may exacerbate sympathetic dominance, altering HRV dynamics. Advancing research in this area may uncover novel, low-cost strategies for psychophysiologic modulation and rehabilitation for conditions not limited to vasovagal syncope, anxiety disorders, and autonomic dysfunction.
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Adeniyi, M., Awosika, A. (2026). Impact of Intermittent Voluntary Facial Expressions on Orthostatic Electroencephalogram. Journal of Nature and Science of Medicine. https://doi.org/10.4103/jnsm.jnsm_83_25