Myocardial and vascular responses to challenge: A comparison of hypertensive and normotensive individuals

The purpose of this study was to examine differences between hypertensives and normotensives at baseline and in cardiovascular responses to three stressors (mirror tracing, cold pressor, and evaluated speech) and to determine if responder type groups (i.e., myocardial and vascular responders, and low reactors) within blood pressure status groups responded differently to these stressors. Healthy, unmedicated, mild hypertensives (n = 29) and normotensives (n = 29), Blacks and Whites, men and women, 25-54 years of age, served as subjects and were matched on the basis of age, sex, race, height, and weight. Using regression-derived cut scores, subjects were classified into 3 responder types (i.e., myocardial and vascular responders, and low reactors) based on their cardiac output and total peripheral resistance (TPR) responses to the presentation phase of the speech task. The proportion of hypertensives was comparable across responder types $(p \u3e .05)$.At baseline, hypertensives had significantly greater TPR $(p \u3c .01)$ than normotensives, whereas normotensives had significantly greater Heather Index than hypertensives $(p \u3c .01)$. After adjusting for baseline, main effects for blood pressure status revealed that hypertensives had a significantly greater increase in blood pressure than normotensives during evaluated speech and mirror tracing as well as for TPR during mirror tracing (all p\u27s $\u3c$.05).Among vascular responders, hypertensives were more reactive in blood pressure than normotensives to the speech and mirror tracing tasks. Among myocardial responders, normotensives were more reactive than hypertensives in myocardial responses to mirror tracing and cold pressor. There were no blood pressure status differences for low responders.In conclusion, several differences between hypertensives and normotensives, not apparent in the overall comparisons, were evident once subjects were classified into responder types. Therefore, classifying hypertensive and normotensive subjects into responder types may be useful in determining differences between these groups that are not apparent in the overall comparisons

Elevated body mass index and obesity among ethnically diverse adolescents

To examine trends in prevalence and odds of elevated body mass index (BMI) and obesity among ethnically diverse adolescents. Data from countywide (Miami-Dade) health screenings from 1999-2005. Weight, height, days/week of vigorous activity, hours/day of sedentary activity, parental hypertension, and eating habits were reported. 77,050 adolescents, average age 15.6 years (51% girls, 9.4% White non-Hispanic, 59.2% White Hispanic, 16.4% African American, 7% Black Hispanic, and 8% Black Caribbean). Prevalence and ethnic differences in odds of obesity (BMI > or = 95th percentile) and elevated BMI (BMI > or = 85th percentile), adjusting for academic years, days/week of vigorous activity, and hours/day of sedentary activity. Prevalence of elevated BMI and obesity increased from 1999-2005. Overall, White non-Hispanics had lower odds of obesity and elevated BMI than African Americans and White Hispanics. African American girls displayed higher odds of obesity and elevated BMI than Black Hispanic girls and higher odds of elevated BMI than Black Caribbean girls. African American boys showed higher odds of obesity and elevated BMI than Black Caribbean boys. Black Hispanic girls had greater odds of obesity and elevated BMI than White Hispanic girls, but boys were similar. This study is among the first to examine BMI status in both Black and Hispanic subgroups. Viewing Black and Hispanic ethnic subgroups as homogeneous obscures important weight-related differences. Further research is warranted to determine factors contributing to differential risk

Classification of individual differences in cardiovascular responsivity: The contribution of reactor type controlling for race and gender

Classification of 150 normotensive or mildly hypertensive men and women into myocardial, vascular, or mild reactors was accomplished using a regression-based approach. The method was based on the participants’ cardiac output (CO) and total peripheral resistance (TPR) reactivity to the speech presentation task. This task purportedly can elicit both myocardial and vascular responses. Cut-scores were based on the v-intercept from the linear regression of the CO reactivitv on TPR reactivity and vice versa. A greater percentage of Black men were classified as vascular responders as compared to Black women and White participants. Groups were found to differ on cardiovascular reactivity to the speech preparation, cold pressor, and mirror tracing tasks in predictable ways, after controlling for gender and ethnicity. Groups were also differentiated by ambulatory blood pressure and hypertensive status. The study supports the classification of homogeneous groups of participants based on the relative extent to which myocardial or vascular mechanisms dominate the reactivity to stress

Cardiometabolic Risk in Adolescents: Associations with Physical Activity, Fitness, and Sleep

Physical activity and fitness are independently associated with cardiometabolic dysfunction, and short sleep duration is an emerging marker of obesity. Few have examined interrelations among these factors in a comprehensive risk model.Investigate the influence of behavioral and lifestyle risk factors on the metabolic syndrome and inflammation.A sample of 367 15–17-year-olds (73 % boys) from ethnic minority groups (45.8 % Hispanic, 30.8 % Black), most with elevated blood pressure (72 %), underwent aerobic fitness testing, blood sampling, and completed behavioral questionnaires.Structural model results are consistent with the notion that short sleep duration, poor sleep quality and fatigue, and decreased physical activity are associated with increased risk of metabolic syndrome and inflammation possibly via effects on reduced cardiorespiratory fitness.The combination of negative lifestyle and behavioral factors of physical inactivity, sleep loss, and poor fitness has serious implications for cardiovascular health complications in at-risk youth

Are Self-Efficacy and Weight Perception Associated With Physical Activity and Sedentary Behavior in Hispanic Adolescents?

Little is known about the correlates of physical activity and sedentary behavior in Hispanic adolescents. This study examined at baseline and 2-year follow-up: (1) the relationship between self-efficacy for physical activity and physical activity, (2) the association of weight perception with physical activity and sedentary behavior, and (3) whether sex moderated these associations. Hispanic adolescents ( N = 483 at baseline; age 15-17 years; 55.1% girls) completed questionnaires that assessed their self-efficacy for physical activity, weight perception, and time spent in physical activity and sedentary behavior. Multiple-group path analyses were conducted to examine the proposed relationships and determine whether they were moderated by sex. Models controlled for body mass index, weight loss intention, participation on a sports team, language spoken at home, parental education, and country of birth. Self-efficacy was related to time spent in physical activity in boys ( b = .35, p < .001) and girls ( b = .41, p < .001) at baseline, but not 2 years later. No association was found for weight perception and time spent in physical activity and sedentary behavior. Post hoc analyses for overweight participants at baseline showed that weight perception was associated with time spent watching television. Overall, the findings suggest that self-efficacy is an important correlate, but not a predictor, of physical activity among Hispanic adolescents. Including strategies to address and enhance self-efficacy for physical activity in lifestyle interventions may increase adherence to physical activity recommendations and help reduce the high prevalence of obesity in this population

Cardiovascular reactivity and cardiometabolic risk in adolescents

Cardiovascular reactivity has been examined as a risk marker or factor in the pathogenesis of hypertension or cardiovascular disease, but few have examined the relationship with the metabolic syndrome. We examined whether cardiovascular reactivity to laboratory stress is associated with individual cardiometabolic risk factors and their co-occurrence. A significant positive relationship was hypothesized for both individual and clustered risk factors in their cross-sectional associations with reactivity to multiple stressors. A sample of 144, 15-17-year-old adolescents (74 % boys) largely from ethnic minority groups (54 % Hispanic White, 26 % Black) were identified at annual blood pressure (BP) screening (39 % with elevated BP) at high schools in Miami, Florida, USA. Participants completed the evaluated speaking, mirror star tracing, and cold pressor tasks, as well as cardiometabolic risk factor blood sampling. Participants were classified into metabolic syndrome criterion groups (0, 1, 2, or ≥3 criteria) based on American Heart Association adult criteria. Multiple regression analyses with individual metabolic syndrome variables demonstrated that diastolic (D)BP reactivity during the mirror star tracing task accounted for 1.3 %, 3.8 %, and 5.1 % of the respective variances in casual systolic BP, waist circumference, and triglycerides (ps < 0.05). In multinomial logistic regression models, increased DBP reactivity during mirror star tracing and cold pressor tasks, and decreased HR reactivity during the cold pressor, were associated with greater likelihood of risk factor co-occurrence (ranging from 8.3 % to 15.8 %). Findings indicate that autonomic reactivity to the mirror star tracing and cold pressor tasks, but not the evaluated speaking task, is associated with risk factor co-occurrence, and reactivity may be a clinical prognosticator of cardiometabolic disease risk

Use of Item Response Theory to Examine a Cardiovascular Health Knowledge Measure for Adolescents with Elevated Blood Pressure

<p>The purpose of this study was to assess the psychometric properties of a cardiovascular health knowledge measure for adolescents using item response theory. The measure was developed in the context of a cardiovascular lifestyle intervention for adolescents with elevated blood pressure. Sample consisted of 167 adolescents (mean age = 16.2 years) who completed the Cardiovascular Health Knowledge Assessment (CHKA), a 34-item multiple choice test, at baseline and post-intervention. The CHKA was unidimensional and internal consistency was .65 at pretest and .74 at posttest. Rasch analysis results indicated that at pretest the items targeted adolescents with variable levels of health knowledge. However, based on results at posttest, additional hard items are needed to account for the increase in level of cardiovascular health knowledge at post-intervention. Change in knowledge scores was examined using Rasch analysis. Findings indicated there was significant improvement in health knowledge over time [t(119) = -10.3, p&lt; .0001]. In summary, the CHKA appears to contain items that are good approximations of the construct cardiovascular health knowledge and items that target adolescents with moderate levels of knowledge.</p><p> </p><p> </p><p>DOI: 10.2458/azu_jmmss.v3i1.16111</p