Activation of the alternative complement pathway and production of factor H by skeletal myotubes

Recent negative findings regarding differences in blood pressure (BP) and heart rate (HR) reactivity at work between Type A and Type B workers may stem from the failure to note the stressors to which they were exposed. In this naturalistic study, an objective work stressor--varying levels of ambient noise--was individually monitored among 123 normotensive males. We examined the relationship of Type A behavior (assessed by the Thurstone Temperament Schedule) to ambulatory BP and HR reactivity under high and low noise conditions. We also tested the hypothesized mediating function of tension arousal. Results of multiple regression analyses indicated that when workers were exposed to high noise levels (> or = 80 dB(A)), Type A behavior was positively related to diastolic BP (p = 0.029) and HR reactivity (p = 0.0001), even after adjusting for clinic values, time of measurement, worker activities, and body position during measurement. When the same workers were exposed to low noise levels, the results were not significant. This suggests that noise constitutes a stressor for Type A individuals, and highlights the importance of noting the actual stressor-exposure condition. In addition, Type A individuals reported high tension, noted concurrently with the ambulatory measurements. Tension arousal was also related to BP and HR reactivity. Adding the tension variable to the above regressions weakened the relationship between Type A behavior and BP and HR reactivity. Thus, the tension experienced by Type A workers exposed to noise stress may have served as a mediator of cardiovascular reactivity.