Autonomic nerve responses under linear acceleration

Autonomic nerve responses of human subjects were evaluated by frequency analysis of heart rate and pulse plethysmogram under linear acceleration applied to parallel (Z) and perpendicular (Y) to the body axis in supine posture. The acceleration applied were 0.25 G with sinusoidal frequencies, 0.1 to 0.17 Hz. The acceleration loading to Z-axis only induced additional frequency component in the power spectra obtained from heart rate and pulse plethysmogram at the foot finger skin, while no additional response was observed in Y-axis loading. The frequency dependency of the acceleration induced heart rate and pulse plethysmogram components suggested a resonance characteristic at higher frequency than 0.17 Hz. Iris diameter change during the acceleration loading measured by infrared light indicated a correlation to the acceleration. The results suggested that an autonomic hemodynamic modulation may arise from a feedback of low pressure receptors when the slow sinusoidal acceleration is loaded to the body axis.
資料番号: AA0046917003