Efficacy of a school -based intervention on blood pressure and cortisol levels of African American adolescents

The purposes of this quasi-experimental design study were to determine the effects of a school-based health promotion intervention for African American adolescents and to explore the relationship of cardiovascular reactivity and salivary cortisol during physiologic stress to birth weight and family history of hypertension in a selected sample of African American adolescents.;The subjects for this study were African American adolescents between the ages of 14 to 17 years attending an urban high school. The school-based health promotion intervention was a nine-week program that was coordinated within a Person Fitness course. The intervention focused on knowledge, decision-making, diet, and exercise. The independent variables were family history of hypertension, a history of low birth weight, physiologic stress, and a school-based health promotion intervention program. The cold pressor test was used to induce physiologic stress. The dependent variables were blood pressure, cardiovascular reactivity, level of cortisol, diet, and exercise. The variables were measured at three equal intervals within the nine-week course.;The intervention group (n = 31) participated in the Personal Fitness class and the intervention program on health promotion, exercise, nutrition, and prevention of hypertension risk factors. They were instructed to exercise five to six times a week for 30 minutes per day and eat five to six fruits/vegetables per day. The control group (n = 17) participated in the Life Management course. Both groups were asked to complete a nutrition data form, a stress index form, and the cold pressor test for changes in blood pressure and salivary cortisol levels.;Multivariate repeated measures analysis of variance and covariance and t-test were used to determine the changes in blood pressure within subjects, between subjects, and within-subjects-by-between-subjects interactions.;The statistical analysis supports the efficacy of the intervention program in cognitive and behavioral components. Statistical analysis revealed the efficacy of the intervention program in relation to knowledge (p = 0.0001), exercise (p = 0.0001), and intake of fruits and vegetables (p = 0.0001). Statistical analysis did not support significant changes in systolic blood pressure (p = 0.5548), diastolic blood pressure (p = 0.9719), or salivary cortisol levels (p = 0.2469) between groups. There was a significant difference in cardiovascular reactivity in the group with a family history of hypertension (p = 0.0338) and the group with a low birth weight (p = 0.004). There were correlations between changes in blood pressure and family history of hypertension and correlation and between changes of blood pressure and cortisol levels.