Many studies have shown that short sleep duration and/or poor sleep quality is associated with increasing rates of cardiovascular (CVD) mortality and morbidity. One hypothesized explanation for this association has been that sleep loss is a type of chronic stress that induces dysregulation of biological systems that ultimately increase the risk of CVD. One biological system that has been thought to link sleep loss and CVD is the hypothalamus-pituitary-adrenal (HPA) axis. A number of studies using small or convenience samples have addressed the effects of sleep deprivation on cortisol. Only a few studies have examined the association of habitual short sleep duration and/or poor sleep quality with changes in the diurnal cortisol in population based-samples; those studies vary in their methodology and in findings. Another biological system that has been thought to link sleep loss and CVD is the autonomic nervous system (ANS), through overactivation of the sympathetic nervous system (SNS) and/or probably a withdrawal of the parasympathetic nervous system. Experimental studies have shown an association between the sleep stages and markers of the sympathetic system. However, very few studies of habitual sleep duration/sleep quality and ANS markers have been conducted. Even fewer studies have examined the association of habitual sleep duration and/or sleep quality and ANS responses to a stress challenge in a population-based sample. The findings again have been inconsistent probably due to the use of different methodology and different samples. This dissertation used measures of salivary diurnal cortisol as well as cortisol responses to a stress challenge protocol to assess the relationship of habitual sleep duration and/or sleep quality with diurnal cortisol profile in natural conditions and in response to a stress challenge protocol in a laboratory setting. Diurnal cortisol was assessed from up to 16 samples of salivary cortisol for two days. Cortisol responses to a stress challenge were assessed from four salivary samples taken during the stress challenge that was performed in a different day than the diurnal cortisol collection. To examine the relationship of habitual sleep duration and/or sleep quality and markers of the ANS, this dissertation used continuous cardiovascular measures (heart rate and heart rate variability) and four salivary amylase samples obtained during the stress challenge. The stress challenge included mental stress and orthostatic stress. Sleep duration and sleep efficiency (an objective measure of sleep quality) were assessed from 7-day actigraphy and sleep diaries. Insomnia symptoms (a subjective measure of sleep quality) were also assessed using a questionnaire that included the Women’s Health Initiative Insomnia rating scale (WHIIRS). We used mixed models so as to account for the repeated measures of diurnal salivary cortisol levels as well as the responses (reactivity and recovery) to the stress challenge tests. Chapter 1 presents an introduction to this dissertation discussing the relationship between short sleep duration and/or poor sleep quality and CVD morbidity and mortality. Chapter 2 presents a systematic literature review of studies of the association between habitual sleep duration and/or sleep efficiency and markers of neuro-endocrine systems: HPA and ANS. These are plausible mechanisms that link short and/or poor sleep to CVD morbidity and mortality. Chapter 3 presents our analyses of the relationship between short sleep duration and/or poor sleep quality and features of the diurnal cortisol. We hypothesized that those participants whose slept < 6 hours per night or whose sleep efficiency was < 85% would have higher cortisol levels on awakening, flatter cortisol awakening responses (CAR), and higher evening cortisol levels than participants who slept longer or slept better. We found that short sleepers had higher evening cortisol than the longer sleepers and that this association persisted after the adjustment for several known confounders. In chapter 4, we examined how the same groups of participants responded in terms of hormones (cortisol and amylase) and cardiovascular indices (heart rate (HR) and HR variability (HRV)) to a stress challenge test. We hypothesized that those participants who slept for a shorter time or whose sleep was of poorer quality would have more exaggerated responses to and less recovery from a stress challenge test than participants who slept longer or slept better. We found that participants with insomnia had exaggerated high frequency-HRV (HF-HRV) orthostatic reactivity. In an extended analysis, we found that participants who slept less than 7 hours/night had exaggerated heart rate reactivity to a mental stress test compared to participants who slept 7 or more hours/night, but this association was attenuated after adjustment for naps. Paradoxically, we also found that participants who slept less than 7 hours had higher HF-HRV recovery from mental stress compared to longer sleepers (≥7 hours). Short sleep duration or low sleep efficiency was not associated with cortisol or amylase responses to the stress challenge protocol. These findings suggest that sustained high evening cortisol levels and cardiovascular responses to a stress challenge may be among the mechanisms linking short/poor sleep and CV disease.

O presente estudo teve por objetivo estudar as adaptações hemodinâmicas, autonômicas e morfofuncionais cardíacas em ratos hipertensos (SHR) submetidos à estimulação colinérgica crônica, com 2 dosagens diferentes (5 e 15 mg), e associar ao treinamento físico aeróbio, utilizando diferentes enfoques: 1. Avaliação do balanço autonômico tônico da frequência cardíaca (FC) por meio do bloqueio farmacológico com atropina e propranolol; 2. Estudo do balanço autonômico fásico (variabilidade) da FC (intervalo de pulso) e pressão arterial por meio da análise espectral; 3. Análise da sensibilidade barorreflexa por meio da administração de múltiplas e aleatórias doses de fenilefrina e nitroprussiato de sódio; 4. Avaliação ecocardiográfica bidimensional. Para tanto foram utilizados 54 ratos, divididos 2 grandes grupos: treinados (n=27) e sedentários (n=27). Os animais que treinaram, deram inicio ao experimento na 18ª semana de vida, na qual tinha duração de 10 semanas; logo em seguida, os ratos eram colocados em tratamento com brometo de piridostigmina por mais 2 semanas, na 30ª semana, os ratos eram submetidos a cirurgia de canulação, para posterior análise da pressão arterial, da FC, da variabilidade da frequência cardíaca (VFC) e da variabilidade da pressão arterial (VPAS). Antecedente a cirurgia, os ratos eram levados para o exame de ecocardiografia bidimensional para análise da morfofuncionalidade cardíaca. Foram consideradas estatisticamente significantes as diferenças em que p for menor que 5%. Os resultados mostraram uma diminuição dos valores de PAS, PAD e PAM, além de diminuir a FC basal e a FC intrínseca nos ratos tratados com 5 e 15 mg de brometo, tanto sedentários quanto tratados. Também houve um aumento de LF (ms2) e uma diminuição de HF (ms2), mostrando melhora na condição autonômica cardíaca. Os principais achados na morfofuncionalidade sugerem um aumento da FE, VE, DC, IC e VDF e VSF, além de observarmos um aumento tanto da área, quanto da espessura do ventrículo esquerdo nos ratos tratados e treinados. Dessa forma, podemos concluir que o tratamento com brometo de piridostigmina foi eficaz quanto aos valores hemodinâmicos, quanto a alguns parâmetros morfofuncionais e quanto à avaliação autonômica cardíaca, sugerindo ser uma boa terapia farmacológica para o tratamento da hipertensão, entretanto, uma investigação mais aprofundada deve ser realizada para um entendimento melhor dos efeitos. Da mesma forma, que o treinamento físico aeróbio promoveu modificações benéficas aos parâmetros avaliados, potencializando a ação do tratamento com o inibidor de acetilcolinesterase. / The objective was to study the hemodynamic changes, autonomic and cardiac morphofunctional in hypertensive rats (SHR) subjected to chronic cholinergic stimulation with two different doses (5 and 15 mg), and associate with the physical training, using different approaches: 1. Assessment tonic autonomic balance, heart rate (HR) by pharmacological blockade with atropine and propranolol; 2. Study of phasic autonomic balance (variability) HR (pulse interval) and blood pressure by spectral analysis; 3. Assessment of baroreflex sensitivity by administration of multiple doses of phenylephrine and random and sodium nitroprusside; 4. Evaluation two-dimensional echocardiography. Therefore, we used 54 rats divided two groups: trained (n = 27) and sedentary (n = 27). The animals trained, gave start to experiment in the 18th week of life, which lasted for 10 weeks; soon after, the rats were placed in treatment pyridostigmine bromide for over 2 weeks, at 30 weeks, the rats were subjected to cannulation surgery for analysis of blood pressure, HR, heart rate variability (HRV) and arterial pressure variability. Antecedent surgery, the rats were brought into the test for dimensional echocardiography analysis of cardiac morfofuncionalidade. Differences were considered statistically significant when p is greater than 5%. The results showed a decrease in SAP, DBP, and MAP, and to decrease the basal HR and HR intrinsic in mice treated with 5 and 15 mg bromide, both sedentary as treated. There was also an increase in NF (MS2) and a decrease in HF (ms2), showing improvement in cardiac autonomic condition. The main findings in morfofuncionalidade suggest an increase in EF, LV, CD, CI and EDV and ESV, and observe an increase in both the area, the thickness of the left ventricle in treated and trained rats. Thus, we can conclude that treatment with pyridostigmine bromide was effective as the hemodynamic values, as some morphological and functional parameters and the cardiac autonomic assessment, suggesting that a good drug therapy for the treatment of hypertension, however, further investigation should It is performed for a better understanding of the effects. Similarly, the physical training promotes beneficial changes to the evaluated parameters, potentiating the action of treatment with acetylcholinesterase inhibitor.

A proposição deste trabalho foi avaliar a resposta do efeito vasomotor simpático, por meio da termografia infravermelha, em pacientes com disfunção temporomandibular (DTM) submetidos à acupuntura. Foram selecionados 17 pacientes com diagnóstico de DTM muscular e articular. Todos receberam tratamento de acupuntura com aplicação dos seguintes pontos: E6, E44, ID18, TA17, TA23, EX HN3, VB2, VB34, IG4 e F3. Foram realizados exames de termografia antes e depois da acupuntura na primeira e quinta sessões, tendo como áreas de interesse a região facial nas vistas frontal, laterais direita e esquerda. Também foram realizadas medições do nível de dor através da escala visual analógica (EVA) e medida de abertura bucal (AB) antes e depois das sessões. Foi observada uma diminuição da temperatura a curto prazo entre os momentos antes e depois da primeira sessão para a maioria das regiões de interesse analisadas (p<0,05). Porém, a longo prazo, a temperatura em quase todas as regiões analisadas se igualou para os momentos antes da primeira e quinta sessões. O tratamento da DTM com acupuntura resultou numa diminuição da sintomatologia dolorosa e leve melhora na abertura bucal. A termografia infravermelha mostrou-se um método efetivo no monitoramento da reatividade vascular no tratamento para DTM pela acupuntura. / The purpose of this study was to evaluate the response of the sympathetic vasomotor effect, through infrared thermography, in patients with temporomandibular dysfunction (TMD) submitted to acupuncture. Seventeen patients with a diagnosis of muscular and joint TMD were selected. All received acupuncture treatment with application of the following points: ST6, ST44, SI18, SJ17, SJ23, EX HN3, GB2, GB34, LI4, LR3. Thermography exams were performed before and after acupuncture in the first and fifth sessions, with areas of interest in the frontal region, right and left sides. Pain level measurements were also performed through visual analogue scale (EVA) and mouth opening measurement (AB) before and after the sessions. A short-term temperature decrease between the time before and after the first session was observed for most of the regions of interest analyzed (p <0.05). However, in the long run, the temperature in all regions analyzed equaled the moments before the first and fifth sessions. There was an improvement of the painful symptomatology and slight increase of the oral opening with acupuncture treatment for TMD. Infrared thermography showed to be an effective method for monitoring vascular reactivity in the treatment of TMD by acupuncture.

Submitted by Fabíola Silva (fabiola.silva@famerp.br) on 2017-09-29T16:44:34Z No. of bitstreams: 1 aracysatoemniwa_dissert.pdf: 1545109 bytes, checksum: ee953654407e190e40b0a0810b11f2be (MD5) / Made available in DSpace on 2017-09-29T16:44:34Z (GMT). No. of bitstreams: 1 aracysatoemniwa_dissert.pdf: 1545109 bytes, checksum: ee953654407e190e40b0a0810b11f2be (MD5) Previous issue date: 2016-09-30 / Introduction: The human skin is 15% of the total body weight and has a vital function to promote the homeostasis of the organism by means of thermoregulation, hemodynamic control, production and excretion of metabolites. Hyperhidrosis (HH) is a pathological condition in which sweat production by the sweat glands is increased beyond the normal physiological needs of the body required to maintain thermo homeostasis. The pathophysiology of Focal Primary Hyperhidrosis (HHPF) remains poorly understood despite suggesting evidence of the occurrence of hyperactivity of the sympathetic nervous system. Objective: To investigate the functions of the Autonomic Nervous System (ANS), in patients with HHPF compared to a control group, apparently healthy, matched by gender, age and body mass index, using the HRV analysis in the time domain, frequency and nonlinearity. Material and Methods: 34 patients with primary hyperhidrosis focal, and the control group of 34 subjects were submitted to analysis of HRV in the time domain, frequency and non-linearity and the results were compared. Results: HRV parameters including mean RR, SDNN, RMSSD, PNN50, low frequency (LF) and high frequency (HF), did not show any difference between the two groups. The same occurred in the nonlinear domain, the SD1 parameters, SD2, ApEn, RP_Lmean% and REC. Conclusion: The findings suggest that the pathophysiology of the Focal Primary Hyperhidrosis , may be due to the peripheral involvement of the sympathetic nervous system (glandular level or nerve endings) since there was no difference between groups. More specific studies should help to elucidate the problem. / Introdução: A pele humana corresponde a 15% do peso total do corpo e tem como função vital promover a homeostasia do organismo por meio da termorregulação, controle hemodinâmico, produção e excreção de metabolitos. Hiperidrose (HH) é a condição patológica na qual a produção do suor pelas glândulas sudoríparas está aumentada além das necessidades fisiológicas normais do organismo requerida para manter a termo homeostasia. A fisiopatologia da hiperidrose primária focal (HHPF) permanece pouco compreendida apesar de sugerir a ocorrência de hiperatividade do sistema nervoso simpático. Objetivo: investigar as funções do Sistema Nervoso Autonômico (SNA), em pacientes com HHPF comparativamente a um grupo controle, aparentemente saudável, pareado por gênero, idade e índice de massa corporal, utilizando a análise da VFC nos domínios do tempo, da frequência e da não linearidade. Material e Método: 34 pacientes portadores de Hiperidrose Primária Focal, e o grupo controle de 34 indivíduos, foram submetidos à análise da VFC nos domínios do tempo, da frequência e da não linearidade e os resultados foram comparados. Resultados: os parâmetros da VFC incluindo RR médio, SDNN, RMSSD, PNN50, baixa frequência (LF) e alta frequência (HF), não evidenciaram qualquer diferença entre os dois grupos. O mesmo ocorreu no domínio não linear, nos parâmetros SD1, SD2, ApEn, RP_Lmean e %REC. Conclusão: os achados sugerem que a Hiperidrose Primária Focal do ponto de vista fisiopatológico, pode ser devida ao comprometimento periférico do sistema nervoso simpático (nível glandular ou de terminações nervosas) já que não houve diferença entre os grupos estudados. Estudos mais específicos deverão ajudar na elucidação do problema.

La fibromyalgie (FM) touche 1,4 à 2,2 % de la population générale avec une nette prédominance féminine (80 % des sujets). Ce syndrome est caractérisé par des douleurs chroniques diffuses, des troubles du sommeil, des troubles cognitifs, des perturbations émotionnelles et une fatigue chronique. Les mécanismes physiopathologiques de la FM ne sont pas complètement élucidés. Cependant, la FM est considérée comme un syndrome lié au stress. Des déséquilibres du système nerveux autonome (SNA) et de l'axe hypothalamo-hypophyso-surrénalien (HHS) ont été mis en évidence dans la FM. Ce déficit de l’axe du stress (SNA et HHS) induirait secondairement des dysfonctionnements des contrôles endogènes de la douleur. A partir de cette hypothèse et en s’appuyant sur deux essais cliniques, notre objectif est d’évaluer l'efficacité d'un programme d’entraînement spécifique, sur les douleurs et les symptômes des patientes FM. Une première étude observationnelle de cinq ans, démontre qu’une prise en charge globale, associée à un entraînement physique spécifique [3 sessions de 45 minutes par semaine d’entraînement continue à intensité modérée (MICT), progressivement couplé à un entraînement fractionné à haute intensité (HIIT)] améliore considérablement les symptômes de la FM. Les premiers résultats d'une seconde étude, contrôlée et randomisée de 24 mois, confirment des dysfonctionnements des mécanismes de modulation centrale de la douleur, ainsi qu’un déficit de la régulation autonome, chez au moins une fraction des patientes FM. Ce programme d’entraînement spécifique, encadré et individualisé, dont l’intensité des exercices est définie pour rééquilibrer la balance neurovégétative (tonus parasympathique et réactivité sympathique), permettrait via des mécanismes de neuroplasticité centrale, associés aux effets périphériques tels que l'augmentation de la perfusion vasculaire au niveau musculaire, de soigner la fibromyalgie. / Fibromyalgia affects 1.4–2.2% of the general population, predominately women (more than 80% of subjects). This syndrome is characterised by chronic widespread pain, sleep disturbances, cognitive dysfunction, emotional disorders and chronic fatigue.Physiopathological mechanisms of FM are not fully elucidated but FM is considered a stress related syndrome. Studies on the stress axis in FM have demonstrated dysfunction of both the Autonomic Nervous System (ANS) and the Hypothalamic-Pituitary-Adrenal (HPA) axis. This stress axis deficit (ANS and HPA) could consequently induce dysregulation of pain modulation. According to this hypothesis and using two clinical trials, our main objective is to assess the efficacy of a specific training program on pain and symptoms in female fibromyalgia patients.Firstly, a 5-year observational study shows that overall care coupled with specific physical training [3 sessions of 45 minutes per week of Moderate Intensity Continuous Training (MICT) gradually associated with High Intensity Interval Training (HIIT)] may lead to dramatic improvement of FM symptoms. Secondly, the initial results of a 24-month, controlled, randomised trial (RCT) confirm dysregulation of central pain modulation and a deficit of the autonomic balance, at least in a percentage of FM patients. This specific, supervised, individualised training program with exercise intensity defined to rebalance the neurovegetative system (parasympathetic tone and sympathetic reactivity), associated by peripheric effects as the improvement of muscle perfusion, may allow FM to be treated through central neuroplasticity.

L’insomnie, une condition fréquemment retrouvée dans la population, se caractérise d’abord par une difficulté à initier ou à maintenir le sommeil et/ou par des éveils précoces le matin ou encore par un sommeil non-réparateur. Lorsqu’elle n’est pas accompagnée par des troubles psychiatriques ou médicaux ou un autre trouble de sommeil et qu’elle perdure plus de 6 mois on parle alors d’insomnie primaire chronique. Selon certains, cette condition serait associée à un état d’hyperéveil caractérisé par une augmentation de l’activité autonome sympathique durant le sommeil et l’éveil. Le baroréflexe est un important mécanisme de contrôle à court terme des fluctuations de la tension artérielle (TA) et de la fréquence cardiaque agissant sur le cœur et les vaisseaux sanguins par l’entremise du système nerveux autonome. On appelle sensibilité baroréceptive (SBR) la capacité du baroréflexe de réagir et de contrôler les fluctuations de TA en modulant le rythme cardiaque. De manière générale, la SBR serait augmentée durant la nuit par rapport à la journée. Aussi, il semblerait que le baroréflexe soit impliqué dans le phénomène de baisse physiologique de la TA pendant la nuit. Or, des données de notre laboratoire ont démontré une augmentation de la TA systolique au cours de la nuit ainsi qu’une atténuation de la baisse nocturne de TA systolique chez des sujets avec insomnie primaire chronique comparé à des témoins bons dormeurs. De plus, il a été démontré que le baroréflexe était altéré de façon précoce dans plusieurs troubles cardiovasculaires et dans l’hypertension artérielle. Or, il semblerait que l’insomnie soit accompagnée d’un risque accru de développement de l’hypertension artérielle. Ces études semblent aller dans le sens d’une altération des mécanismes de régulation de la TA dans l’insomnie. Par ailleurs, une réduction de la SBR serait aussi impliquée dans des états associés à une augmentation de l’activité autonome sympathique. Ainsi, nous nous sommes demandé si le baroréflexe pouvait constituer un des mécanismes de contrôle de la TA qui serait altéré dans l’insomnie et pourrait être impliqué dans l’augmentation de l’activité sympathique qui semble accompagner l’insomnie. Jusqu’à présent, le baroréflexe reste inexploré dans l’insomnie. L’objectif principal de ce mémoire était d’évaluer de façon non-invasive la SBR à l’éveil et en sommeil chez 11 sujets atteints d’insomnie primaire chronique comparé à 11 témoins bons dormeurs. L’évaluation du baroréflexe a été effectuée de façon spontanée par la méthode de l’analyse en séquence et par le calcul du coefficient alpha obtenu par l’analyse spectrale croisée de l’intervalle RR et de la TA systolique. De façon concomitante, les paramètres de la variabilité de l’intervalle RR en sommeil et à l’éveil ont aussi été comparés chez ces mêmes sujets. Aucune différence significative n’a été notée au niveau des index de la SBR entre le groupe d’insomniaques et celui des bons dormeurs, à l’éveil ou en sommeil. Cependant, on observe des valeurs légèrement plus faibles de la SBR chez les insomniaques ayant mal dormi (efficacité de sommeil (ES) < 85%) comparés aux insomniaques ayant bien dormi (ES≥ 85%) à la nuit expérimentale durant l’éveil et en sommeil. Par ailleurs, aucune différence n’a été notée entre le groupe d’insomniaques et celui des bons dormeurs au niveau des paramètres de la variabilité RR considérés (intervalle RR, PNN50, LF et HF en valeurs normalisées). En effet, les insomniaques tout comme les bons dormeurs semblent présenter une variation normale de l’activité autonome en sommeil, telle que représentée par les paramètres de la variabilité RR. Ces résultats préliminaires semblent suggérer que les mécanismes du baroréflexe sont préservés chez les sujets atteints d’insomnie primaire chronique tels que diagnostiqués de manière subjective. Cependant, il est possible qu’une altération des mécanismes du baroréflexe ne se révèle chez les insomniaques que lorsque les critères objectifs d’une mauvaise nuit de sommeil sont présents. / Insomnia, one of the most common sleep complaint in the general population, is characterised firstly by a difficulty initiating or maintaining sleep and/or early awakenings or non-restorative sleep. Insomnia is defined as primary when not principally due to another medical or psychiatric condition or other sleep disorder, whereas a minimum of 6 months duration is required to define chronic insomnia. Some authors have hypothesized that insomnia is associated with a state of hyperarousal characterized by increased sympathetic activity during sleep and wakefulness. The arterial baroreflex is an important mechanism providing continuous short term regulation of heart rate and blood pressure (BP) by means of the autonomic nervous system influences over the pacemaker and the peripheral circulation. Baroreflex sensitivity (BRS) is the baroreflex’s capacity to react and control BP changes by adjusting the heart rate. BRS is known to be heightened during the night compared to daytime. Also, it seems that the baroreflex could be involved in the physiological day-to-night BP fall. Previous data from our laboratory demonstrated in subjects with chronic primary insomnia, higher night-time systolic BP and a significant attenuation of the physiologic day-to-night systolic BP fall compared to good sleepers. Besides, the baroreflex has been shown to be altered early in several cardiovascular diseases and to precede hypertension. Subjects with insomnia have been shown to have a higher likelihood to develop daytime hypertension. All of these findings point in the direction of altered BP regulatory mechanisms in insomnia. Furthermore, a reduction of BRS could be implicated in states where higher sympathetic autonomic activity is observed. We hypothesised that the baroreflex could be one of the BP control mechanisms which are altered in insomnia and could be involved in the heightened sympathetic activity observed in insomnia. To our knowledge, the baroreflex has never been investigated previously in insomnia. The primary goal of this study was to investigate non-invasively BRS during wakefulness and sleep in 11 subjects with chronic primary insomnia compared to 11 good sleepers. Baroreflex was investigated spontaneously by the sequence method and by the calculation of the alpha coefficient obtained by cross spectral analysis of RR interval and systolic BP. Simultaneously, RR interval variability components were also compared during wakefulness and sleep between the two groups. No significant differences were found for indices of BRS between insomniacs and good sleepers during wakefulness and sleep. However, slightly lower values of BRS during wakefulness and sleep were noted in insomniacs with poor sleep (sleep efficiency (SE) <85%) versus those with good sleep (SE≥ 85%) at the experimental night. As a secondary finding, no differences were found between the insomniacs and the good sleepers for any of the RR variability components considered (RR interval, PNN50, LF and HF in their normalized units). Indeed, insomniacs like good sleepers exhibited normal variation of autonomic activity during sleep as depicted by the RR variability components. Our preliminary results suggest that baroreflex mechanisms are preserved in subjects with a subjective complaint of chronic primary insomnia. Nevertheless, certain impairment may occur in insomniacs as a function of objective measures of poor sleep.

Playing violent video games may provoke aggression. Psycho-physiological methods may provide knowledge about the underlying psychological processes. Most previous studies have been performed in laboratory settings at daytime with adults. Thus the aim of this thesis was to investigate psycho-physiological (autonomic and HPA related reactions), sleep-related and emotional responses in teenage boys to playing a violent and a non-violent video game at home before going to sleep. In Study I the autonomic responses differed between the violent and the non-violent game during playing and more distinctly during sleep. In Study II the HPA axis was not affected by video gaming at all. In Study III, the effect of habits of playing violent games was assessed (≤ 1h/day and ≥ 3h/day). High versus low experience of violent gaming were related to different autonomic, sleep-related and emotional processes at exposure to a violent and a non-violent game, during playing and during sleep. The present thesis demonstrated that violent and non-violent games induce different autonomic responses during playing and – more distinctly – during sleep. Frequent gaming seems to influence physiological, sleep-related and emotional reactions, possibly as an expression of desensitization processes.

Background: Despite advances in the treatment of atherosclerosis, cardiovascular disease is the leading cause of death worldwide. With the population getting older and more obese, the burden of cardiovascular disease may further increase. Premenopausal women are relatively protected against cardiovascular disease compared to men, but the reasons for this sex difference are partly unknown. Redistribution of body fat from peripheral to central depots may be a contributing factor. Central fat is associated with hyperlipidemia, hyperglycemia, hypertension, and insulin resistance. Two possible mediators of these metabolic disturbances are tissue-specific production of the stress hormone cortisol and adipose tissue blood flow (ATBF). The aim of this thesis was to determine the adipose tissue production of cortisol by the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) and to investigate the regulation of ATBF. Materials and Methods: Cortisol release was estimated by labeled cortisol infusions and tissue-specific catheterizations of subcutaneous and visceral adipose tissue (VAT) in men. We investigated ATBF by 133Xe-washout and its relation to autonomic activity, endothelial function, adipose tissue distribution, and adipokines in different groups of women. We further investigated the effect of two diets and of weight loss on ATBF in women. Results: We demonstrated significant cortisol release from subcutaneous adipose tissue in humans. Splanchnic cortisol release was accounted for entirely by the liver. Cortisol release from VAT (to the portal vein) was not detected. ATBF decreased according to increasing weight and postmenopausal status, and the level of blood flow was associated with nitric oxide (NO) activity and autonomic activity. ATBF was also highly associated with leptin levels and both subcutaneous adipose tissue and VAT areas. After 6 months of diet and weight reduction, a significant difference in ATBF was observed between diet groups. Conclusions: Our data for the first time demonstrate the contributions of cortisol generated from subcutaneous adipose tissue, visceral tissues, and liver by 11β-HSD1. ATBF is linked to autonomic activity, NO activity, and the amount of adipose tissue (independent of fat depot). Postmenopausal overweight women exhibited a loss of ATBF flexibility, which may contribute to the metabolic dysfunction seen in this group. Weight loss in a diet program could not increase the ATBF, although there were ATBF differences between diet groups. The results will increase understanding of adipose tissue biology and contribute to the development of treatment strategies targeting obesity and obesity-related disorders.

Thesis (MSc. (Physiology)--Faculty of Health Sciences) - University of Pretoria, 2005. / Includes bibliographical references.

Orientador: Carlos Marcelo Pastre / Banca: Luiz Carlos Marques Vanderlei / Banca: Moacir Fernandes de Godoy / Resumo: O sistema nervoso autônomo (SNA) desempenha um papel importante na regulação dos processos fisiológicos do organismo humano tanto em condições normais quanto patológicas. Dentre as técnicas utilizadas para sua avaliação, a variabilidade da frequência cardíaca (VFC) tem emergido como uma medida simples e não-invasiva dos impulsos autonômicos, representando um dos mais promissores marcadores quantitativos do balanço autonômico. A VFC descreve as oscilações no intervalo entre batimentos cardíacos consecutivos (intervalos R-R), assim como oscilações entre frequências cardíacas instantâneas consecutivas. Trata-se de uma medida que pode ser utilizada para avaliar a modulação do SNA sob condições fisiológicas, tais como em situações de vigília e sono, diferentes posições do corpo, treinamento físico, e também em condições patológicas. Mudanças nos padrões da VFC fornecem um indicador sensível e antecipado de comprometimentos na saúde. Uma alta variabilidade na frequência cardíaca é sinal de boa adaptação, caracterizando um indivíduo saudável, com mecanismos autonômicos eficientes, enquanto que, baixa variabilidade é frequentemente um indicador de adaptação anormal e insuficiente do SNA, implicando a presença de mau funcionamento fisiológico no indivíduo. Diante da sua importância como um marcador que reflete a atividade do SNA sobre o nódulo sinusal e como uma ferramenta clínica para avaliar e identificar comprometimentos na saúde, este artigo revisa aspectos conceituais da VFC, dispositivos de mensuração, métodos de filtragem, índices utilizados para análise da VFC, limitações de utilização e aplicações clínicas da VFC. / Abstract: Autonomic nervous system (ANS) plays an important role in the regulation of the physiological processes of the human organism during normal and pathological conditions. Among the techniques used in its evaluation, the heart rate variability (HRV) has arising as a simple and non-invasive measure of the autonomic impulses, representing one of the most promising quantitative markers of the autonomic balance. The HRV describes the oscillations in the interval between consecutive heart beats (RR interval), as well as the oscillations between consecutive instantaneous heart rates. It is a measure that can be used to assess the ANS modulation under physiological conditions, such as wakefulness and sleep conditions, different body positions, physical training and also pathological conditions. Changes in the HRV patterns provide a sensible and advanced indicator of health involvements. Higher HRV is a signal of good adaptation and characterizes a health person with efficient autonomic mechanisms, while lower HRV is frequently an indicator of abnormal and insufficient adaptation of the autonomic nervous system, provoking poor patient's physiological function. Because of its importance as a marker that reflects the ANS activity on the sinus node and as a clinical instrument to assess and identify health involvements, this study reviews conceptual aspects of the HRV, measurement devices, filtering methods, indexes used in the HRV analyses, limitations in the use and clinical applications of the HRV. / Mestre