Thoracic bioelectrical impedance assessment of the hemodynamic reactions to recorded road-traffic noise in young adults

Abstract

Noise exposure increases blood pressure in both experimental and field studies. The underlying mechanisms may be evaluated by thoracic bioelectrical impedance. The aim of this experimental study was to assess changes in blood pressure, cardiac and hemodynamic parameters provoked by recorded traffic noise in young adults. The study included 130 participants (42 men and 88 women), aged 24.88±2.67 years. Thoracic electrical bioimpedance device was applied to monitor cardiac parameters, hemodynamic parameters, heart rate variability, blood pressure and heart rate. The testing procedure consisted of three phases. Participants were exposed to recorded road-traffic noise (Leq=89dBA) for 10min and relaxed in quiet conditions (Leq=40dBA) before and after noise exposure. Listening to recorded noise resulted in significant decrease of stroke volume and cardiac output, and an increase of vascular resistance. Heart rate variability and the overall sympathovagal balance remained similar through all experimental conditions. During noise exposure, systolic pressure increased by 2mmHg among women (95% confidence interval=0.97-2.73mmHg), and by 4mmHg among men (95% confidence interval=2.16-5.00mmHg). Similarly, diastolic pressure increased by 2mmHg among women (95% confidence interval=0.95-2.47mmHg), and by 4mmHg among men (95% confidence interval=2.46-5.28mmHg). Once noise ceased, both pressures returned to pre-exposure levels. Experimental exposure to recorded road-traffic noise of 89dBA for 10min provoked significant hemodynamic changes in young adults, including vasoconstriction (increase of vascular resistance), and hypodynamics (decrease of global heart flow). The interaction of these effects resulted in the elevation of blood pressure during noise exposure.

Keywords: Blood pressure; Hemodynamics; Impedance cardiography; Noise.