Independent and Combined Effects of Physical Activity and Sedentary Behavior on Blood Pressure in Adolescents: Gender Differences in Two Cross-Sectional Studies

Objectives: To examine the independent and combined association of physical activity (PA) and sedentary behavior (SB) on both systolic (SBP) and diastolic blood pressure (DBP) in adolescents from two observational studies. Methods: Participants from two cross-sectional studies, one conducted in Europe (n = 3,308; HELENA study) and the other in Brazil (n = 991; BRACAH study), were selected by complex sampling. Systolic and diastolic blood pressure (outcomes), PA and SB, both independently and combined, and potential confounders were analyzed. Associations were examined by multilevel linear regression. Results: Performing the recommended amount of PA (≥60 min/d) attenuated the effect of SB on DBP in BRACAH study girls and in boys from both studies. In contrast, PA did not attenuate the effects of SB on the SBP of girls in the HELENA study. The combination of less than recommended levels of PA with 2-4 h/d of sedentary behavior was found to be associated with increased SBP in boys from both studies. Conclusions: Meeting current PA recommendations could mediate the association between SB and DBP in both sexes. In boys, the joint effect of low levels of PA and excessive sedentary activity increases SBP levels. Longitudinal studies are required to confirm these findings. © 2013 de Moraes et al.

Evaluation of the Omron MX3 Plus monitor for blood pressure measurement in adolescents

This study analyzed the accuracy/agreement of the Omron MX3 monitor on 165 adolescents. Blood pressure was measured by the automatic monitor connected in Y with the mercury column (three consecutive and simultaneous measures). The independent measures were analyzed, and the mean differences between systolic and diastolic measures for both methods were calculated and compared with British Hypertension Society (BHS) and Association for the Advancement of Medical Instrumentation (AAMI) criteria. The automatic monitor received the highest degree of BHS recommendations for systolic and diastolic blood pressures according to the BHS. The median (25th and 75th) difference between the observer and the monitor measurements was -2 (-6 and 1) mmHg for systolic and 0 (-3 and1) mmHg for diastolic pressures. The monitor also satisfies the AAMI standard for the studied population. In conclusion, the Omron MX3 Plus monitor can be considered reliable and valid for clinical practice and is in accordance with BHS and AAMI criteria.

Ambulatory blood pressure monitoring in children with obstructive sleep apnea and primary snoring

Objective: To evaluate the systemic blood pressure (BP) during daytime and nighttime in children with sleep breathing disorders (SBD) and compare parameters of BP in children with diagnosis of obstructive sleep apnea syndrome (OSA) to those one with primary snoring (PS).Methods: Children, both genders, aged from 8 to 12 years, with symptoms of SBD realized an overnight polysomnography followed by a 24 h recording of ambulatory BP.Results: All subjects presented with a history of snoring 7 nights per week. Children who have apnea/hipoapnea index >= four or a apnea index >= one presented a mean BP of 93 +/- 7 mmHg and 85 +/- 9 mmHg diurnal and nocturnal respectively whereas children who have a apnea/hipoapnea < four or a apnea index < one presented 90 +/- 7 mmHg and 77 +/- 2 mmHg. Eight children out of fourteen, from OSA group, lost the physiologic nocturnal dipping of the blood pressure. Among OSA children 57% were considered non-dippers. Two (16%) have presented absence of nocturnal dipping among children with primary snoring. The possibility of OSA children loosing physiologic blood pressure dipping was 6.66 higher than the possibilities of patients from PS group.Discussion: Our results indicate that children with sleep apnea syndrome exhibit a higher 24 h blood pressure when compared with those of primary snoring in form of decreased degree of nocturnal dipping and increased levels of diastolic and mean blood pressure, according to previous studies in literature. OSA in children seems to be associated to the development of hypertension or other cardiovascular disease. (C) 2012 Elsevier B.V. All rights reserved.

Independent impact of glycemia ad blood pressure in albuminuria on high-risk subjects for metabolic syndrome

Background: Microalbuminuria may reflect diffuse endothelial damage. Considering that diabetes and hypertension cause vasculopathy, we investigated associations of albumin-to-creatinine ratio (ACR) with plasma glucose and blood pressure levels in high-risk subjects for metabolic syndrome. Methods: A sample of 519 (246 men) Japanese-Brazilians (aged 60 ± 11 years), who participated in a population-based study, had their ACR determined in a morning urine specimen. Backward models of multiple linear regression were created for each gender including log-transformed values of ACR as dependent variable; an interaction term between diabetes and hypertension was included. Results: Macroalbuminuria was found in 18 subjects. ACR mean values for subjects with normal glucose tolerance, impaired fasting glycemia, impaired glucose tolerance and diabetes were 9.9 ± 6.0, 19.0 ± 35.4, 20.7 ± 35.4, and 33.9 ± 55.0 mg/g, respectively. Diabetic subjects showed higher ACR than the others (p < 0.05). An increase in the proportion of albuminuric subjects was observed as glucose metabolism deteriorated (4.9, 17.0, 23.0 and 36.0%). Stratifying into 4 groups according to postchallenge glycemia (< 7.8 mmol/l, n = 9 1; ≥ 7.8 mmol/l, n = 4 10) and hypertension, hypertensive and glucose-intolerant subgroups showed higher ACR values. ACR was associated with gender, waist circumference, blood pressure, plasma glucose and triglyceride (p < 0.05); albuminuric subjects had significantly higher levels of such variables than the normoalbuminuric ones. In the final models of linear regression, systolic blood pressure and 2-hour glycemia were shown to be independent predictors of ACR for both genders (p < 0.05). In men, also waist was independently associated with ACR. No interaction was detected between diabetes and hypertension. Conclusions: These findings suggest that both glucose intolerance and hypertension could have independent but not synergistic effects on endothelial function - reflected by albumin loss in urine. Such hypothesis needs to be confirmed in prospective studies. © 2004 Dustri-Verlag Dr. K. Feistle.

Influence of arginine vasopressin receptor and nitric oxide on the water, sodium intake and arterial blood pressure induce by angiotensin injected into third ventricle of the brain

As several structures of the central nervous system are involved in the control of hydromineral and cardiovascular balance we investigated whether the natriorhexigenic and pressor response induced by the injection of ANG II into the 3rd V could be mediated by vasopressinergic and nitrergic system. Male Holtzman rats weighing 200-250 g with cannulae implanted into the 3rd V were used. The drugs were injected in 0.5 μL over 30-60 sec. Controls were injected with a similar volume of 0.15 M NaCl. ANGII increased the water intake vs control. AVPA injected into 3rd V prior to ANGII decreased the dipsogenic effect of ANGII. L-arginine also decreased the water intake induced by ANGII. AVPA plus L-arginine inhibit the water intake induced by ANGII. 7NIT injected prior to ANGII potentiated the dipsogenic effect of ANGII. Pre-treatment with ANGII increased the sodium ingestion vs control. AVPA decreased the ANGII effect in sodium intake. L-arginine also decreased the natriorhexigenic effect of ANGII. The combination of L-arginine and AVPA inhibit the sodium intake induced by ANGII. 7NIT injected prior to ANGII potentiated the sodium intake induced by ANGII. ANGII induced an increase in Mean Arterial Pressure (MAP) vs control. AVPA and L-arginine induced a decreased in the pressor effect of ANGII. The combination of L-arginine and AVPA inhibit the pressor effect of ANGII. 7NIT injected prior to ANGII into 3rd V potentiated the pressor effect of ANGII. These data suggest that arginine vasopressin V 1 receptors and Nitric Oxide (NO) within the circumventricular structures may be involved in sodium intake and pressor response induced by the activation of ANGII receptors within the circumventricular neurons. These studies revealed the involvement of sodium appetite by utilizing the angiotensinergic, vasopressinergic and nitrergic system in the central regulation of blood pressure. © 2006 Asian Network for Scientific Information.

Control of breathing and blood pressure by parafacial neurons in conscious rats

New Findings: • What is the central question of this study? The main purpose of the present manuscript was to investigate the cardiorespiratory responses to hypoxia or hypercapnia in conscious rats submitted to neuronal blockade of the parafacial region. We clearly showed that the integrity of parafacial region is important for the respiratory responses elicited by peripheral and central chemoreflex activation in freely behavior rats. • What is the main finding and its importance? Since the parafacial region is part of the respiratory rhythm generator, they are essential for postnatal survival, which is probably due to their contribution to chemoreception in conscious rats. The retrotrapezoid nucleus (RTN), located in the parafacial region, contains glutamatergic neurons that express the transcriptor factor Phox2b and that are suggested to be central respiratory chemoreceptors. Studies in anaesthetized animals or in vitro have suggested that RTN neurons are important in the control of breathing by influencing respiratory rate, inspiratory amplitude and active expiration. However, the contribution of these neurons to cardiorespiratory control in conscious rats is not clear. Male Holtzman rats (280-300 g, n= 6-8) with bilateral stainless-steel cannulae implanted into the RTN were used. In conscious rats, the microinjection of the ionotropic glutamatergic agonist NMDA (5 pmol in 50 nl) into the RTN increased respiratory frequency (by 42%), tidal volume (by 21%), ventilation (by 68%), peak expiratory flow (by 24%) and mean arterial pressure (MAP, increased by 16 ± 4, versus saline, 3 ± 2 mmHg). Bilateral inhibition of the RTN neurons with the GABAA agonist muscimol (100 pmol in 50 nl) reduced resting ventilation (52 ± 34, versus saline, 250 ± 56 ml min-1 kg-1 with absolute values) and attenuated the respiratory response to hypercapnia and hypoxia. Muscimol injected into the RTN slightly reduced resting MAP (decreased by 13 ± 7, versus saline, increased by 3 ± 2 mmHg), without changing the effects of hypercapnia or hypoxia on MAP and heart rate. The results suggest that RTN neurons activate facilitatory mechanisms important to the control of ventilation in resting, hypoxic or hypercapnic conditions in conscious rats. © 2012 The Authors. Experimental Physiology © 2012 The Physiological Society.

Aquatic Exercise is as Effective as dry Land Training to Blood Pressure Reduction in Postmenopausal Hypertensive Women

Background and Purpose: The evidence of the benefits from regular physical activity to hypertensives is based on dry land training studies. Therefore, the aim of this study is to compare the effect of aquatic exercise with dry land training on hypertensive women. Methods: This is a randomized controlled study with 52 post-menopausal hypertensive women. The patients were randomly allocated in three groups: water aerobic training group (n=19), dry land aerobic training group (n=19) and a non-intervention control group (n=14). The training protocol was performed by 12weeks. Results: There were no differences among the three groups concerning basal blood pressure (BP) and biochemical variables. In water group, there was a statistically significant reduction of systolic BP from 136±16mmHg at zero week to 124±18mm Hg at 11th week and 124±15mmHg at 12th week. In dry land training group, there was a statistically significant reduction of systolic BP from 138±15mmHg at zero week to 125±10mmHg at 7th week, 127±10mmHg at 10th week and 126±9mmHg at 12th week. The control group presented no change in any of the assessed variables. No changes were carried out in any antihypertensive medications during study. Discussion: This is a randomized controlled study that demonstrates the antihypertensive efficacy of aerobic aquatic exercise. © 2013 John Wiley & Sons, Ltd.

Prevalence of high blood pressure in Brazilian adolescents and quality of the employed methodological procedures: systematic review

OBJETIVO:Revisar a literatura sobre estudos que estimaram a prevalência de pressão arterial elevada (PAE) ou hipertensão arterial sistêmica (HAS) em adolescentes brasileiros, considerando os procedimentos metodológicos empregados.MÉTODOS:Pesquisa bibliográfica de estudos de prevalência de PAE/HAS em adolescentes de 1995 a 2010. A busca foi realizada nas bases de dados eletrônicos PubMed/Medline, Lilacs, SciELO, Isi e Adolec. Foram utilizados os descritores: hipertensão, pressão arterial, adolescente, estudantes, estudos transversais, prevalência e Brasil, nas línguas portuguesa e inglesa. Além disso, foi elaborado um escore, baseado nas Recommendations for Blood Pressure Measurement in Humans and Experimental Animals e nas VI Diretrizes Brasileiras de Hipertensão, para a análise dos procedimentos utilizados para medida da PA nos estudos variando de 0 a 18.RESULTADOS:Foram identificados 21 artigos, a maioria publicada nos últimos 10 anos, sendo 90,5% realizados em base escolar e nas regiões sudeste, nordeste e sul do país. As prevalências de PAE/HAS variaram de 2,5 a 30,9%. A pontuação dos estudos variou de 0 a 16. Foi observada uma correlação negativa significante (rho = -0,504; p = 0,020) entre a prevalência de PAE/HAS e o escore da qualidade da medida da PA.CONCLUSÃO:A grande variabilidade das estimativas da PAE/HAS parece ser influenciada pelos procedimentos metodológicos utilizados nos estudos.

Involvement of the median preoptic nucleus in blood pressure control

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The Association Between Cardiovascular Risk Factors and High Blood Pressure in Adolescents: A School-Based Study

Objective: Although previous studies have analyzed the association between cardiovascular risk factors and blood pressure in adolescents, few studies conducted in developing countries analyzed whether the aggregation of risk factors contributes to an increased risk of high blood pressure in adolescents. The objective of this study was to assess the association between cardiovascular risk factors (including general overweight, abdominal obesity, high consumption of foods rich in fats, and insufficient physical activity levels) and high blood pressure in adolescents.Methods: This study was carried out from 2007 to 2008 with 1021 adolescents (528 girls) from primary schools located in the city of Londrina- Brazil. Blood pressure was assessed using an oscillometric device. General overweight was obtained through body mass index, abdominal obesity was assessed using waist circumference, and the consumption of foods rich in fat and physical activity were assessed using a questionnaire. The sum of these risk factors was determined.Results: Adolescents with three or four aggregated risk factors were more likely to have higher values of systolic and diastolic blood pressure when compared with adolescents who did not have any cardiovascular risk factors (P = 0.001 for both). Logistic regression indicated that groups of adolescents with 2 (OR = 2.46 [1.11-5.42]; P = 0.026), 3 (OR = 4.97 [2.07-11.92]; P = 0.001) or 4 risk factors (OR = 6.79 [2.24-19.9]; P = 0.001) presented an increased likelihood of high blood pressure.Conclusions: The number of cardiovascular risk factors was found to be related to high blood pressure in adolescents. (C) 2014 Wiley Periodicals, Inc.

High sodium intake during postnatal phases induces an increase in arterial blood pressure in adult rats

Coordenadoria de Aperfeiçoamento em Pesquisa (CAPES)

The presence of the NOS3 gene polymorphism for intron 4 mitigates the beneficial effects of exercise training on ambulatory blood pressure monitoring in adults

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Daily intake of pasteurized orange juice decreases serum cholesterol, fasting glucose and diastolic blood pressure in adults

Previous studies have shown that fresh squeezed orange juice or juice from reconstituted concentrate can help prevent the development of atherosclerosis. Pasteurized orange juice presently represents the major orange juice available in the market, and because of this, it becomes necessary to determine the healthy benefits associated with this product. In this study we investigated the effect of regular consumption of pasteurized orange juice on the nutritional status, biochemical profile, and arterial blood pressure in healthy men and women. Men and women volunteered to consume pasteurized orange juice (500 mL·d–1 and 750 mL·d–1, respectively), for 8 weeks. Anthropometric, biochemical, hemodynamic, and dietary assessments were evaluated at baseline and at the end of the experimental period. Total cholesterol and LDL-C significantly decreased in both men and women after the consumption of orange juice, and an increase in HDL-C level was detected exclusively in women. Fasting glucose, diastolic blood pressure, and triglyceride levels dropped in men after the consumption of orange juice. Anthropometric variables did not change with orange juice consumption, only waist circumference decreased significantly in women. Consumption of orange juice increased the energy and carbohydrate intake for women; however, vitamin C and folate increased after the orange juice period for both men and women. Regular consumption of pasteurized orange juice by men (750 mL·d–1) and women (500 mL·d–1) reduced the risk of developing atherosclerosis, and increased the nutritional quality of their diets.