Industrial noise exposure and ambulatory blood pressure and heart rate.

Studies on the effects of long-term exposure to industrial noise on resting blood pressure have yielded inconsistent results. Ambulatory blood pressure and heart rate were monitored simultaneously with noise exposure in normotensive male industrial workers in Israel (85 aged 25 to 44 and 77 aged 45 to 65 years). In the younger group, average ambulatory systolic blood pressure was 3.2 mm Hg higher and diastolic blood pressure 2.3 mm Hg higher in subjects exposed to more than 85 dBa (P less than .001), after adjusting for potential confounding variables. In those aged 45 to 65, ambulatory systolic blood pressure was 3.3 mm Hg lower and diastolic blood pressure unchanged in noise-exposed subjects. Ambulatory heart rate was 2.7 and 2.6 beats per minute higher at the higher noise level (P = .002) in the respective age groups. These findings suggest that industrial noise exposure is associated with higher ambulatory blood pressure and heart rates in men under 45 years old, but the effect on blood pressure appears to diminish considerably with age.