Int. J. Environ. Res. Public Health 2010, 7 3462 and no significant school x type of acute stressor interaction effect (F1,182 = 0.92, p = 0.34). Follow-up ANCOVAs were conducted to evaluate the simple effects of school within type of acute stressor. These analyses, and the data in Figure 1, revealed that noisy-school children had lower SBP reactivity than quiet-school children during both the math (F1,182 = 8.53, p = 0.004) and noise challenge (F1,182 = 3.95, p = 0.048). School accounted for approximately twice as much variance in SBP reactivity during the math challenge (partial Eta-squared = 0.045) than during the noise challenge (partial Eta-squared = 0.021). Analyses of DBP reactivity revealed no significant main effect of school (F1,182 = 3.46, p = 0.064), no significant main effect of type of acute stressor (F1,182 = 2.43, p = 0.121), and no significant school x type of acute stressor interaction effect (F1,182 = 1.11, p = 0.29). However, inspection of the means and standard errors in Figure 1 indicated that the schools did differ in DBP reactivity to the math challenge. Thus, follow-up ANCOVAs were conducted to evaluate the simple effects of school within type of acute stressor. These analyses revealed that noisy-school children had significantly lower DBP reactivity than quiet-school children during the math challenge (F1,182 = 4.65, p = 0.032), but not during the noise challenge (F1,182 = 0.79, p = 0.376). School accounted for a relatively small proportion of the variance (partial Eta-squared = 0.025) in DBP reactivity during the math challenge. Figure 1. Systolic 1 and diastolic 2 blood pressure reactivity during acute math and noise stressors among children in the quiet versus noisy elementary school (n = 189). 1 Means adjusted for sex, age, BMI, testing problems, and resting systolic blood pressure. 2 Means adjusted for sex, age, BMI, testing problems, and resting diastolic blood pressure. 4. Discussion Results of this quasi-experimental study revealed no link between traffic noise exposure at school and resting blood pressure in a sample of urban elementary school boys and girls in India. These findings contradict work on aircraft noise and children’s resting blood pressure, but generally match findings on traffic noise [1,2]. Thus one way to interpret the present results is lack of support for the hypothesis that chronic noise exposure raises blood pressure. However several prior studies have also