Impact of Transcendental Meditation on cardiovascular function at rest and during acute stress in adolescents with high normal blood pressure

Intermittent food deprivation improves cardiovascular and neuroendocrine responses to stress in rats

Stressful events may trigger disease processes in many different organ systems, with the cardiovascular system being particularly vulnerable. Five-mo-old male rats had ad libitum (AL) access to food or were deprived of food every other day [intermittent food deprivation (IF)] for 6 mo, during which time their heart rate (HR), blood pressure (BP), physical activity and body temperature were measured by radiotelemetry under nonstress and stress (immobilization or cold-water swim) conditions. IF rats had significantly lower basal HR and BP, and significantly lower increases in HR and BP after exposures to the immobilization and swim stressors. Basal levels of adrenocorticotropic hormone (ACTH) and corticosterone were greater in the IF rats. However, in contrast to large stress-induced increases in ACTH, corticosterone and epinephrine levels in AL rats, increases in these hormones in response to repeated immobilization stress sessions were reduced or absent in IF rats. Nevertheless, the IF rats exhibited robust hypothalamic/pituitary and sympathetic neuroendocrine responses to a different stress (swim). The IF treatment improved glucose metabolism, as indicated by lower basal levels of circulating glucose and insulin, but with maintenance of glucose and insulin responses to stress. We concluded that improvements in cardiovascular risk factors and cardiovascular and neuroendocrine stress adaptation occur in response to IF.

Impact of stress reduction on negative school behavior in adolescents

BACKGROUND

The purpose of this study was to determine the effect of stress reduction via the Transcendental Meditation program on school rule infractions in adolescents.

METHODS

Forty-five African American adolescents (ages 15-18 years) with high normal systolic blood pressure were randomly assigned to either Transcendental Meditation (n = 25) or health education control (n = 20) groups. The meditation group engaged in 15-min sessions at home and at school each day for 4 months. The control group was presented 15-min sessions of health education at school each day for 4 months. Primary outcome measures were changes in absenteeism, school rule infractions and suspension days during the four-month pretest period prior to randomization compared with the four-month intervention period.

RESULTS

Comparing the pretest and intervention periods, the meditation group exhibited a mean decrease of 6.4 absentee periods compared to an increase of 4.8 in the control group (p <.05). The meditation group exhibited a mean decrease of 0.1 infractions over the four months compared to an increase of 0.3 in the control group (p <.03). There was a mean reduction of 0.3 suspension days due to behavior-related problems in the meditation group compared to an increase of 1.2 in the control group (p <.04).

CONCLUSION

These findings demonstrate that the Transcendental Meditation program conducted in the school setting has a beneficial impact upon absenteeism, rule infractions, and suspension rates in African American adolescents.

Insulin resistance syndrome and left ventricular mass in healthy young people

BACKGROUND

Findings of atherosclerotic plaques in adolescents, in the context of current epidemics of obesity and type 2 diabetes in youth, demand investigation into early cardiovascular risk development. Left ventricular hypertrophy has been linked to hypertension, obesity, and insulin resistance.

METHODS

Insulin resistance syndrome characteristics (fasting glucose and insulin; systolic blood pressure; waist girth) were measured in 70 normotensive, normoglycemic young people (60% male, 62% black; included 13 twin pairs; age mean +/- SD, 19 +/- 2.6 years). Left ventricular mass indexed by height (2.7) (LVMI) was obtained via ultrasound. Twin pairs were clustered to satisfy the assumption for independent observations.

RESULTS

LVMI was regressed on insulin after controlling for race, gender, and systolic blood pressure. Insulin was a significant (P = 0.02) independent predictor of LVMI (R(2)change = 0.09, P < 0.01). Waist girth accounted for an additional 4% variance of LVMI (P = 0.05). A one-factor model comprising waist (factor loading = 0.83), insulin (0.59), glucose (0.42), and LVMI (0.46) showed good fit [chi2(2) = 0.41, P = 0.81; root-mean-square error of approximation = 0.0].

CONCLUSIONS

A subclinical metabolic syndrome is detectable early in life, before abnormal fasting glucose or high blood pressure appear. Evidence of excessive load on the heart is associated with the metabolic syndrome even after accounting for the effects of race, gender, and blood pressure. Cardiac structure seems as closely associated with this syndrome as fasting glucose level. Based on this evidence, we propose that increased left ventricular mass is a part of insulin resistance syndrome and adds to the need for preventive public health measures to improve health behaviors and cardiovascular risk status in US youth.

Reproducibility of ambulatory blood pressure measures in African-American adolescents

OBJECTIVE

The primary purpose of this study was to evaluate the reproducibility of ambulatory blood pressure (BP) measures in African-American (AA) adolescents.

METHODS

Forty-one AA adolescents (age 16.6 +/- 1.3 yrs, 16F) with high-normal BP were measured on 3 occasions at 2-month intervals. Systolic BP (SBP), diastolic BP (DBP), and heart rate (HR) measures were recorded using the Spacelabs ambulatory BP monitor 90207 (Redmond, Wash) in the natural environment over 24-hour periods. Mixed model repeated measures ANOVAs were used to analyze the underlying error variance-covariance (V-C structures as well as mean differences for the 3 visits.

RESULTS

Daytime measures: there were no significant mean differences across visits for daytime SBP, DSP, and HR (all Ps > .57). The error V-C matrix was heterogeneous Toeplitz for daytime SBP. Correlations between visits 1 and 2, 1 and 3, and 2 and 3 for daytime SBP were rs = 0.71, 0.47, and 0.71, respectively. Compound symmetry (CS) was the preferred model for daytime DBP (r = 0.68) and HR (r = 0.75). Nighttime measures: there were no significant mean differences across visits for nighttime SBP, DBP, and HR (all Ps > .29). The error V-C matrix was unstructured for nighttime SBP. Correlations between visits 1 and 2, 1 and 3, and 2 and 3 for SBP were rs = 0.74, 0.33, and 0.33, respectively. CS was preferred for night-time DBP (r = 0.58) and HR (r = 0.74).

CONCLUSION

Collectively, these findings demonstrate that 3 measurements of ambulatory-derived DBP and HR measures are stable across 4 months, but SBP was only stable across 2 months in African-American adolescents.

Psychosocial stress and cardiovascular disease Part 2: effectiveness of the Transcendental Meditation program in treatment and prevention

Psychosocial stress is a nontraditional risk factor for cardiovascular morbidity and mortality that may respond to behavioral or psychosocial interventions. To date, studies applying such interventions have reported a wide range of success rates in treatment or prevention of cardiovascular disease (CVD). The authors focus on a natural medicine approach that research indicates reduces both psychosocial and traditional risk factors for cardiovascular disease-the Transcendental Meditation (TM) program. Randomized controlled trials, meta-analyses, and other controlled studies indicate this meditation technique reduces risk factors and can slow or reverse the progression of pathophysiological changes underlying cardiovascular disease. Studies with this technique have revealed reductions in blood pressure, carotid artery intima-media thickness, myocardial ischemia, left ventricular hypertrophy, mortality, and other relevant outcomes. The magnitudes of these effects compare favorably with those of conventional interventions for secondary prevention.