CARDIOVASCULAR EFFECTS OF SHORT TERM NOISE OF A CONSTANT FREQUENCY AND INTENSITY

Abstract

The term noise is commonly used to describe sounds that are disagreeable or unpleasant. Noise has become a very important ‘stress factor’ in the environment of man. Noise has many effects on exposed population. Many experts have investigated the acute effects of short-term loud noise on cardiovascular parameters. The main objective of this study was to observe the effect of exposure to short-term noise on blood pressure and heart rate. Methods: One hundred and seventeen normotensive medical students (61 male and 56 female), aged 18 23 years were exposed to 90 dB sound of 4000 Hz for 10 minutes. Blood pressure and heart rate was measured at regular 3-minute intervals before, during, and after the production of noise. The subjects selected for the study were themselves control group by exposing them to experimental conditions, without production of noise. Results: Systolic blood pressure, diastolic blood pressure, pulse pressure, mean arterial pressure and heart rate increased in 57.26%, 70.94%, 34.19%, 73.50% and 88.89% of the total subjects, respectively; while the pulse pressure decreased in 44.44% of the total subjects. Average rise in systolic blood pressure, diastolic blood pressure, pulse pressure, mean arterial pressure and heart rate was 2.462 mm Hg, 3.064 mm Hg, 0.42 mm Hg, 2.157 mm Hg and 8.938 respectively (p<0.05). Conclusion: Blood pressure and heart rate increase during exposure to noise and remain elevated for a certain period of time, usually 2–11 minutes, even after exposure to noise.