Sedentary behavior is linked to numerous adverse effects on a person’s health, such as obesity, depression, and a higher risk of cardiovascular events. Professions that are primarily sedentary have increased due to the growth of office-related occupations, one of which is software engineering. A potential intervention to reduce sedentary behavior is to utilize new interactive technologies such as virtual reality (VR) to change the work context and allow software engineers to interact with their work environment in a more embodied manner. This study has designed and evaluated a visual programming language (VPL) in VR for its potential to reduce sedentary behavior and its compromise on usability. Ten participants solving simple programming tasks using the VPL in VR revealed the potential of reducing continuous sedentary behavior with light physical activity. The main contributor to this activity was the need to walk to and from interactive elements placed a few meters from each other in the design. However, the usability evaluation showed that users modify the environment over time to reduce this distance such that less walking is needed. In contrast, movement induced by navigating to code blocks and getting an overview of the current state of the work had positive marks and a high contribution to the observed movement. Lastly, the second contributor to physical activity was moving blocks around. The usability evaluation indicates that using VR controllers was slower than using a mouse but allowed more precise interactions. / Stillasittande beteende har ett flertal negativa effekter på en persons hälsa, såsom obesitas, depression och en högre risk för kardiovaskulära händelser. Yrken som främst är stillasittande har ökat på grund av tillväxten av yrken som är kontorsbaserade, till exempel mjukvaruutveckling. Ett potentiellt ingripande för att minska stillasittande beteende är att använda nya interaktiva tekniker, så som virtuell verklighet (VR) för att förändra arbets kontexten och låta mjukvaruingenjörer interagera med sin arbetsmiljö på ett mer förkroppsligat sätt. Denna studie har utvecklat och utvärderat en visuellt programmeringsspråk (VPL) i VR för dess potential att minska stillasittande beteende och dess kompromiss på användbarhet. Tio deltagare som löste enkla programmeringsuppgifter med hjälp av VPL i VR visade potentialen för att bryta upp stillasittande beteende med lätt fysisk aktivitet. Den främsta bidragsgivaren till den observerade aktivitet var behovet av att gå till och från interaktiva element placerade med några meter avstånd från varandra. Utvärderingen visade dock att användare modifierar miljön över tid för att minska detta avstånd så att man behöver gå mindre. Däremot hade rörelser när man behöver navigera till kodblock och få en överblick över arbetet positiva kommentarer och ett högt bidrag till den observerade aktiviteten. Slutligen var aktiviteten att flytta runt block den handling som bidrog näst mest till den observerade fysisk aktivitet. Utvärderingen av användbarheten indikerar att VR-kontroller var långsammare än att använda en mus men tillät mer tillförlitliga interaktioner.

No description available.

No description available.

No description available.

Master of Public Health / Department of Human Nutrition / Mark Haub / Background: Time spent in sedentary behaviors, independent of physical activity levels, is a risk factor for chronic diseases and all-cause mortality. It is unknown whether physically active adults alter their dietary and/or physical activity behaviors in response to imposed sedentary time. The aim of this study was to determine whether imposing 10 hours of sedentary time per week for 8 weeks would alter physical activity and/or dietary profiles of physically active adults. Methods: Sixteen physically active, healthy young adults were randomized into either the no-intervention control (CON) group (n=8) or the sedentary-intervention (SIT) group (n=8). SIT participants attended monitored sedentary sessions for 10 hours per week (4 days; 2.5 hours) for 8 weeks. Assessments occurred at baseline, and weeks 4 and 8. Dietary information was collected through 3-day food records and physical activity was assessed through 7 days of accelerometry (Actical at the wrist). Results: There were no differences in physical activity profiles in SIT or CON groups when baseline and week-8 average (average weeks) were compared to the week-4 assessment. Differences in step counts comparing the average weeks and week 4 were not significantly different between CON and SIT groups (CON = 615.1 ± 3019.1, SIT= -1158.0 ± 3373.0 steps, p=0.287). There were no differences in sedentary (p=0.366), light (p=0.293), moderate (p=0.656) or vigorous (p=0.701) physical activity when average weeks were compared to one of imposed sedentary behavior. A greater number of SIT (4/8) participants had lower step counts during the imposed sedentary week, when compared to CON (1/8) participants. There was no difference (p>0.05) between CON and SIT groups for total calories consumed at any time-point. Caloric intake decreased significantly in the SIT group compared to the CON group (SIT = -27.9 ± 22.8%, CON = 10.0 ± 37.6%, p=0.028). More SIT (7/8) than CON (3/8) participants decreased caloric intake from baseline to 8 weeks (p>0.05). Conclusion: Physically active young adults did not alter physical activity profiles, but did decrease their caloric intake, in response to 8 weeks of imposed sedentary time. These findings may indicate a compensatory mechanism to imposed sitting in physically active adults.

Objetivos: Identificar o padrão de atividade física (AF) e de tempo sentado (TS), bem como os fatores associados, na população de 30 anos e mais, residente no município de Ribeirão Preto-SP, Brasil, em 2006 e comparar dois critérios utilizados para a classificação do padrão de AF: International Physical Activity Questionnaire - (IPAQ) e American College of Sports Medicine/American Heart Association (ACSM/AHA). Métodos: Estudo epidemiológico transversal, de base populacional, com processo de amostragem desenvolvido em três estágios. A variabilidade introduzida na terceira fração de amostragem foi corrigida pela atribuição de pesos amostrais, que levaram em consideração a taxa de não resposta e o número de unidades elegíveis em cada domicílio, originando uma amostra ponderada de 2197 participantes. Para avaliar o padrão de AF e do TS, utilizou-se o Questionário IPAQ (versão curta). Para identificar fatores associados ao padrão de AF, aplicou-se o modelo de regressão de Poisson, obtendo-se razões de prevalência, por pontos e por intervalos com 95% de confiança, em modelos uni e multivariados. Para a identificação dos fatores associados ao TS foram construídos modelos de regressão linear múltipla, obtendo-se os coeficientes angulares (?) e respectivos intervalos, com 95% de confiança, em modelos uni e multivariados. Todas as estimativas foram calculadas levando-se em consideração o efeito do desenho amostral. Para a comparação entre os critérios do IPAQ e do ACSM/AHA, utilizou-se a estatística Kappa, estimada por pontos e por intervalos com 95% de confiança. Resultados: Na amostra do estudo, 62,5% dos homens e 67,9% das mulheres apresentaram \"prática insuficiente\" de AF. Diferentes variáveis permaneceram associadas à \"prática insuficiente\" (PI) nos modelos finais. No sexo masculino, permaneceram: \"nº de horas de trabalho/dia\", \"nº de medicamentos consumidos nos últimos 15 dias\" e \"saúde auto-referida\". No sexo feminino, permaneceram: \"nível educacional\" e \"renda\". Em relação ao tempo sentado, em quase todas as categorias das variáveis estudadas, os homens apresentaram valores médios de TS maiores que as mulheres, sendo que, para o conjunto dos homens, a média diária foi 306,2 minutos e, para as mulheres, 270,3 minutos. Na análise multivariada permaneceram associadas ao TS as seguintes variáveis: \"sexo\", \"anos de escolaridade\", \"hábito de fumar\", \"gasto metabólico (Mets*min*semana-1)\", \"nº de horas de trabalho/dia\" e \"nº de antecedentes de obesidade\". As prevalências de prática suficiente de AF foram, em geral, discretamente mais elevadas quando aplicados os critérios do ACSM/AHA, em relação ao do IPAQ. A estatística Kappa indicou acordo satisfatório entre estes critérios (Kappa?1), em ambos os sexos, sendo os coeficientes gerais kmasc=0,95 (IC95% 0,83-1,06) e kfem=0,93 (IC95% 0,85-1,01). Conclusões: Os critérios do IPAQ e do ACSM/AHA apresentaram praticamente a mesma capacidade de classificação dos participantes quanto aos níveis de AF. Os resultados indicaram prevalência de PI e média de TS elevadas na população. As associações encontradas reforçam a necessidade de implantação de Programas específicos de promoção da prática de AF e diminuição do TS, tendo em vista que diferentes conjuntos de fatores permaneceram associados a estes desfechos. Tais Programas podem contribuir para a adoção de um estilo de vida saudável, bem como para a prevenção de doenças crônico-degenerativas nesta população. / Objectives: Identify the physical activity (PA) and sitting time (ST) pattern, as well as correlates, in the population aged 30 years and older living in Ribeirão Preto-SP, Brazil, in 2006 and compare two criteria used to classify the PA pattern: International Physical Activity Questionnaire - (IPAQ) and American College of Sports Medicine/American Heart Association (ACSM/AHA). Methods: A cross-sectional population-based epidemiological research was carried out using three-stage sampling. The variability introduced in the third sampling fraction was corrected by attributing sampling weights, which considered the non-response rate and number of eligible units at each household, resulting in a weighted sample of 2197 participants. To assess the PA and ST pattern, the IPAQ questionnaire (short version) was used. To identify PA correlates, Poisson\'s regression model was applied to estimate prevalence ratios, by point and 95% confidence intervals, in crude and multivariate models. To identify ST correlates, multiple linear regression models were used to estimate angular coefficients (?) and their respective intervals, at a 95% confidence level, in crude and multivariate models. All estimates were calculated taking into account the sample design effect. To compare IPAQ and ACSM/AHA criteria, Kappa statistics were used, by point and 95% confidence intervals. Results: In the study sample, 62.5% of men and 67.9% of women showed \"insufficient practice\" of PA. Different variables remained associated with \"insufficient practice\" (IP) in the final models. Among men, remained associated: \"number of work hours/day\", \"number of drugs consumed in last 15 days\" and \"self-related health\". Among women, remained associated: \"educational level\" and \"income\". With regard to sitting time, in almost all categories of the research variables, men showed higher ST means than women, with a daily average of 306.2 minutes for men, and 270.3 minutes for women. In multivariate analysis, remained associated with ST: \"gender\", \"years of education\", \"smoking\", \"metabolic waste (Mets*min*week-1)\", \"number of work hours/day\" and \"number of obesity antecedents\". In general, prevalence rates for sufficient practice were slightly higher when applying ACSM/AHA criteria in comparison with IPAQ. Kappa statistics indicated satisfactory agreement between these criteria (Kappa?1), in both genders, with crude coefficients kmale=0.95 (CI95% 0.83-1.06) and kfem=0.93 (CI95% 0.85-1.01). Conclusions: The IPAQ and ACSM/AHA criteria showed practically the same ability to classify participants in terms of PA levels. The results indicated high IP prevalence and ST means in the population. The associations found reinforce the need to implement specific Programs of PA promotion and ST decrease, as different sets of factors remained associated with these outcomes. These Programs can contribute to the adoption of a healthy lifestyle and to the prevention of chronic-degenerative diseases in this population.

Pré-escolares não estão praticando o mínimo de atividade física (AF) segundo diretrizes internacionais, isto tem provocado o aumento do sedentarismo infantil e prejuízos ao desenvolvimento integral. Entre os fatores que podem influenciar a prática de AF, nesta faixa etária, estão as pessoas e os ambientes envolvidos diretamente com as crianças. Assim, o objetivo principal da pesquisa foi verificar o que pais e professores pensam sobre desenvolvimento infantil e como isto se reflete na oferta de atividades físicas para préescolares. Foi realizada uma pesquisa de campo com 438 adultos (197 professores e 241 pais e responsáveis de crianças em idade pré-escolar) provenientes de cinco municípios da região metropolitana de Palmas/TO. Os participantes responderam dois questionários com 35 perguntas sobre o perfil sociodemográfico, atividades realizadas pelas crianças dentro e fora da escola, o que era necessário para a criança se desenvolver e hábitos de AF. Este estudo tem um desenho ecológico e a análise do microssistema mostrou que a frequência diária de AF dentro e fora da escola é baixa (11% e 12%), enquanto que as atividades que facilitam o comportamento sedentário foram oferecidas por 28% e 30% dos professores e pais respectivamente. Quanto aos aspectos necessários para a criança se desenvolver, ambos os grupos priorizaram as necessidades básicas, o acompanhamento familiar e as atividades de leitura, escrita e cálculo. O perfil sociodemográfico dos participantes também influenciou na oferta de atividades físicas (idade, nível de escolaridade e renda). O mesossistema apontou para uma contradição entre a importância e a frequência diária das AF no ambiente escolar e domiciliar e também uma diferença nas respostas indicadas por pais e professores. O exossistema revelou que os hábitos de AF dos pais e professores estavam associados a indicação de oferta de prática para as crianças. O macrossistema identificou que a má qualidade da educação infantil, a falta de AF da população, problemas com formação e capacitação profissional e as crenças dos adultos dificultam a inclusão de prática de atividade física para pré-escolares. Os contextos analisados e a não valorização da AF como um dos aspectos prioritários para o desenvolvimento infantil podem limitar as oportunidades de escolha e dificultar a realização de estratégias que revertam os baixos níveis de AF entre préescolares sendo necessário fomentar a aproximação e o dialogo entre a escola e a família. / Among home and school: practice of physical activity and child development Preschoolers are not practicing the minimum of physical activity (PA) according to international guidelines, it has caused the increase of the infant sedentary lifestyle and damages to the integral development. Among the factors which can influence the practice of PA in this age group are people and environments directly involved with children. Thus, the main objective of this research was verifying what parents and teachers think about child development and what way this reflected in the offer physical activities for preschoolers. A field research was done involving 438 adults (197 teachers and 241 parents and guardians of preschool children) from five counties in the metropolitan region of Palmas, the capital of Tocantins State. The participants have answered two questionnaires with 35 questions were about the socio demographic profile, to the activities performed by the children inside and outside of school, a question about what is need for the child development and another about the PA habits. This study has an ecological design and the analysis of the microsystem has showed that the daily frequency of PA inside and outside of school is low (11% and 12%), whereas the activities which can facilitate sedentary behavior were daily offered by 28% and 30% of teachers and parents, respectively. As to necessary aspects for the child development, both groups prioritized the basic necessities, family accompaniment and activities reading, writing, and calculating. The socio demographic profile of the participants has also influenced the offer of the practice of physical activity (age, level education and income). The mesosystem was verified an contradiction between the importance and the daily frequency of PA in the school and home environment, there was also a difference in the answers indicated, which have revealed a discrepancy between the opinion of the parents and teachers. The exosystem has revealed that the PA habits of parents and teachers were associated with indication of the offer of practice for the children. The macrosystem has identified that the poor quality of early childhood education, the lack of PA of the population, the precariousness of professional training programs and beliefs of adults difficult the inclusion the practice of physical activity for preschoolers. The contexts analyzed and the no valorization of the PA as one of the priorities for child development may limit the opportunities of choice and hamper the realization to strategies which reverse the low levels of PA among preschoolers so it is necessary to foster the rapprochement and dialogue between the school and the family.

Objetivos: Identificar o padrão de atividade física (AF) e de tempo sentado (TS), bem como os fatores associados, na população de 30 anos e mais, residente no município de Ribeirão Preto-SP, Brasil, em 2006 e comparar dois critérios utilizados para a classificação do padrão de AF: International Physical Activity Questionnaire - (IPAQ) e American College of Sports Medicine/American Heart Association (ACSM/AHA). Métodos: Estudo epidemiológico transversal, de base populacional, com processo de amostragem desenvolvido em três estágios. A variabilidade introduzida na terceira fração de amostragem foi corrigida pela atribuição de pesos amostrais, que levaram em consideração a taxa de não resposta e o número de unidades elegíveis em cada domicílio, originando uma amostra ponderada de 2197 participantes. Para avaliar o padrão de AF e do TS, utilizou-se o Questionário IPAQ (versão curta). Para identificar fatores associados ao padrão de AF, aplicou-se o modelo de regressão de Poisson, obtendo-se razões de prevalência, por pontos e por intervalos com 95% de confiança, em modelos uni e multivariados. Para a identificação dos fatores associados ao TS foram construídos modelos de regressão linear múltipla, obtendo-se os coeficientes angulares (?) e respectivos intervalos, com 95% de confiança, em modelos uni e multivariados. Todas as estimativas foram calculadas levando-se em consideração o efeito do desenho amostral. Para a comparação entre os critérios do IPAQ e do ACSM/AHA, utilizou-se a estatística Kappa, estimada por pontos e por intervalos com 95% de confiança. Resultados: Na amostra do estudo, 62,5% dos homens e 67,9% das mulheres apresentaram \"prática insuficiente\" de AF. Diferentes variáveis permaneceram associadas à \"prática insuficiente\" (PI) nos modelos finais. No sexo masculino, permaneceram: \"nº de horas de trabalho/dia\", \"nº de medicamentos consumidos nos últimos 15 dias\" e \"saúde auto-referida\". No sexo feminino, permaneceram: \"nível educacional\" e \"renda\". Em relação ao tempo sentado, em quase todas as categorias das variáveis estudadas, os homens apresentaram valores médios de TS maiores que as mulheres, sendo que, para o conjunto dos homens, a média diária foi 306,2 minutos e, para as mulheres, 270,3 minutos. Na análise multivariada permaneceram associadas ao TS as seguintes variáveis: \"sexo\", \"anos de escolaridade\", \"hábito de fumar\", \"gasto metabólico (Mets*min*semana-1)\", \"nº de horas de trabalho/dia\" e \"nº de antecedentes de obesidade\". As prevalências de prática suficiente de AF foram, em geral, discretamente mais elevadas quando aplicados os critérios do ACSM/AHA, em relação ao do IPAQ. A estatística Kappa indicou acordo satisfatório entre estes critérios (Kappa?1), em ambos os sexos, sendo os coeficientes gerais kmasc=0,95 (IC95% 0,83-1,06) e kfem=0,93 (IC95% 0,85-1,01). Conclusões: Os critérios do IPAQ e do ACSM/AHA apresentaram praticamente a mesma capacidade de classificação dos participantes quanto aos níveis de AF. Os resultados indicaram prevalência de PI e média de TS elevadas na população. As associações encontradas reforçam a necessidade de implantação de Programas específicos de promoção da prática de AF e diminuição do TS, tendo em vista que diferentes conjuntos de fatores permaneceram associados a estes desfechos. Tais Programas podem contribuir para a adoção de um estilo de vida saudável, bem como para a prevenção de doenças crônico-degenerativas nesta população. / Objectives: Identify the physical activity (PA) and sitting time (ST) pattern, as well as correlates, in the population aged 30 years and older living in Ribeirão Preto-SP, Brazil, in 2006 and compare two criteria used to classify the PA pattern: International Physical Activity Questionnaire - (IPAQ) and American College of Sports Medicine/American Heart Association (ACSM/AHA). Methods: A cross-sectional population-based epidemiological research was carried out using three-stage sampling. The variability introduced in the third sampling fraction was corrected by attributing sampling weights, which considered the non-response rate and number of eligible units at each household, resulting in a weighted sample of 2197 participants. To assess the PA and ST pattern, the IPAQ questionnaire (short version) was used. To identify PA correlates, Poisson\'s regression model was applied to estimate prevalence ratios, by point and 95% confidence intervals, in crude and multivariate models. To identify ST correlates, multiple linear regression models were used to estimate angular coefficients (?) and their respective intervals, at a 95% confidence level, in crude and multivariate models. All estimates were calculated taking into account the sample design effect. To compare IPAQ and ACSM/AHA criteria, Kappa statistics were used, by point and 95% confidence intervals. Results: In the study sample, 62.5% of men and 67.9% of women showed \"insufficient practice\" of PA. Different variables remained associated with \"insufficient practice\" (IP) in the final models. Among men, remained associated: \"number of work hours/day\", \"number of drugs consumed in last 15 days\" and \"self-related health\". Among women, remained associated: \"educational level\" and \"income\". With regard to sitting time, in almost all categories of the research variables, men showed higher ST means than women, with a daily average of 306.2 minutes for men, and 270.3 minutes for women. In multivariate analysis, remained associated with ST: \"gender\", \"years of education\", \"smoking\", \"metabolic waste (Mets*min*week-1)\", \"number of work hours/day\" and \"number of obesity antecedents\". In general, prevalence rates for sufficient practice were slightly higher when applying ACSM/AHA criteria in comparison with IPAQ. Kappa statistics indicated satisfactory agreement between these criteria (Kappa?1), in both genders, with crude coefficients kmale=0.95 (CI95% 0.83-1.06) and kfem=0.93 (CI95% 0.85-1.01). Conclusions: The IPAQ and ACSM/AHA criteria showed practically the same ability to classify participants in terms of PA levels. The results indicated high IP prevalence and ST means in the population. The associations found reinforce the need to implement specific Programs of PA promotion and ST decrease, as different sets of factors remained associated with these outcomes. These Programs can contribute to the adoption of a healthy lifestyle and to the prevention of chronic-degenerative diseases in this population.

Family Child Care Homes (FCCHs) are the second largest provider of non-relative care in the U.S. However, despite providing care for nearly 1.9 million children under the age of 5, little is known about the physical activity levels of children attending FCCHs. This dissertation sought to provide new information with regards to physical activity in children attending FCCHs. The purpose of the first study was to objectively measure physical activity in children attending FCCHs. 114 children (60 boys and 54 girls) 3.7 �� 1.1 years of age from 47 FCCHs wore an ActiGraph GT1M accelerometer for the duration of child care attendance during a randomly selected week. Counts were classified as sedentary (SED), light (LPA), or moderate-to-vigorous (MVPA) using the cut-points developed by Pate et al. (2006). Total physical activity was calculated by summing time spent in LPA and MVPA. Non-wear time was estimated by summing the number of consecutive zero counts accumulated in strings of 10 minutes or longer. Children were included in the analyses if they had 2 or more monitoring days in which wear time was ���75% of the attendance time. On average, children accumulated 25.9 �� 5.7 min of SED, 10.1 �� 4.2 min of MVPA, and 34.1 �� 5.7 min of total physical activity per hour of attendance. Further analysis revealed that among healthy weight children, 4 year-olds exhibited significantly lower levels of SED and significantly higher levels of MVPA and total physical activity than 2- and 3- year-olds. Among 4-year-olds, overweight and obese children exhibited significantly higher levels of SED and significantly lower levels of MVPA and total PHYSICAL ACTIVITY than healthy weight counterparts. The results from this study indicated that preschool-aged children attending FCCHs are mostly sedentary and accumulate low levels of MVPA during the child care day. The purpose of the second study was to assess the validity of two proxy report instruments designed to measure physical activity in children attending FCCHs. Valid self-report measures are needed for large scale intervention studies and/or population-based surveillance studies in which more burdensome objective measures are not feasible. In Year 1 of the study, FCCH Providers (N=37) completed the Burdette parent proxy report, modified for the family child care setting, for 107 children aged 3.4 �� 1.2 years. In Year 2, 42 Providers completed the Harro parent and teacher proxy report, modified for the family child care setting, for 131 children aged 3.8 �� 1.3 years. Both proxy-reports were assessed for validity using objectively measured physical activity as a criterion measure (accelerometry). Significant positive correlations were observed between scores from the modified Burdette proxy report and objectively measured total physical activity (r = 0.31, p < 0.01) and MVPA (r = 0.33, p < 0.01). Across levels of Provider-reported activity, both total physical activity and MVPA increased significantly in a linear dose-response fashion. Provider-reported MVPA scores from modified Harro proxy report were not associated with objectively measured physical activity. These findings suggested that the modified Burdette proxy report may be a useful measurement tool in larger-scale physical activity studies involving FCCHs in which objective measures, such as direct observation or accelerometry, are not practical. The purpose of the third study was to evaluate the effects of two strategies to increase the use of portable play equipment in FCCHs ��� a community-based train-the-trainer physical activity intervention (INT), and the same trainer-the-trainer intervention supplemented with monthly emails promoting the use of portable play equipment (INT+). We hypothesized that Providers completing the standard train-the-trainer intervention would report significantly greater portable play equipment use than Providers completing the food allergy control training (CON). We further hypothesized that Providers completing the supplementary email intervention would report significantly greater portable play equipment use than Providers completing standard train-the-trainer intervention or the food allergy control training. A total of 50 FCCH Providers from Marion, Linn, Benton, Washington, and Lane County, Oregon were randomized to the INT or CON conditions. Twelve Providers from Lincoln County were assigned to the (INT+). The type, variety, and frequency of portable play equipment use was measured by means of self-report via a checklist and two items from the previously validated NAP-SACC Self-Assessment instrument. FCCH Providers who completed the INT reported significantly greater use of portable play equipment than Providers completing the CON training. However, portable play equipment use among Providers completing the INT+ was not significantly different from that reported by Providers in the INT or CON. Notably, neither intervention had a significant impact on the amount or variety of portable play equipment. The results showed that a comprehensive trainer-the-trainer intervention to increase physical activity in FCCHs could successfully increase the use of portable play equipment in the home. However, supplementing the intervention with monthly emails encouraging the use of PPE was not effective. / Graduation date: 2013

L'athérosclérose est une maladie cardiovasculaire complexe affectant la paroi artérielle où le développement et la progression de la plaque sont fortement favorisés par une inflammation chronique. L'instabilité de la plaque carotidienne peut conduire à de potentiels évènements ischémiques majeurs tels que l'accident vasculaire cérébral (AVC) dont le caractère imprévisible rend la prévention primaire très compliquée. Ainsi, il n'existe pas à l'heure actuelle de biomarqueurs prédictifs efficaces de la rupture de plaque. Néanmoins, il est maintenant clairement établi que l'hémorragie intraplaque (IPH), la néovascularisation et l'accumulation excessive de macrophages sont les principaux facteurs d'instabilité de la plaque. Sur la base de travaux précédents, l'objectif de cette thèse était d'évaluer de manière indépendante les effets de l'activité physique (AP) et de la sédentarité, premièrement sur les paramètres histologiques d'instabilité de plaque, et deuxièmement, sur les facteurs de risque secondaires de l'athérosclérose, que sont l'inflammation, le stress oxydant et le profil hémorhéologique de patients asymptomatiques à risque d'AVC traités chirurgicalement. La 1ère étude a montré que l'AP régulière était associée à une prévalence d'IPH diminuée, et était l'unique facteur protecteur de l'IPH. Cette étude a également suggéré un effet bénéfique de l'AP sur le stress oxydant, ainsi que sur l'accumulation de macrophages. Dans une 2ème étude, nous avons caractérisé l'état fonctionnel de protéines potentiellement impliquées dans les dysfonctions du système immunitaire, et l'implication des cellules inflammatoires dans ces mécanismes. Nous avons alors identifié une cytokine pro-inflammatoire jouant un rôle déterminant dans les processus inflammatoires de déstabilisation de plaque. L'étude 3 nous a permis de caractériser l'effet du niveau d'AP sur la réponse monocytaire chez des patients avec plaque d'athérosclérose, et d'identifier une chimiokine qui pourrait avoir un rôle dans la modulation de la réponse monocytaire par l'AP. Enfin, la 4ème étude démontre l'altération de paramètres hémorhéologiques chez des patients atteints de maladie carotidienne sévère, et comment l'AP permet de limiter cette altération via la diminution de l'agrégation érythrocytaire. Ce travail de thèse apporte des informations quant à la pratique de l'AP dans la prévention primaire de l'athérosclérose. Des études complémentaires seront toutefois nécessaires afin de confirmer ces résultats, en proposant notamment une approche interventionnelle en activité physique / Atherosclerosis is a complex cardiovascular disease that affects the arterial wall where plaque development and progression are severely promoted by chronic inflammation. Carotid plaque destabilization could lead to potential major ischemic events such stroke which is still unpredictable, making primary prevention very complex. Thus, there is still currently no suitable predictive biomarker of plaque rupture. Nevertheless, it is now clearly established that intraplaque hemorrhage (IPH), neovascularization and excessive macrophage accumulation are the three main risk factors of plaque instability. Based on previous studies, the aim of this work was to evaluate independently the impact of physical activity (PA) and sedentary behavior, first on histological parameters of plaque instability, and secondly on secondary risk factors of atherosclerosis, such as inflammation, oxidative stress and hemorheological profile of asymptomatic patients at high-risk of stroke who underwent endarterectomy surgery. The first study shows that regular PA was associated to a decreased occurrence of IPH, and was the only protective factor for IPH. This study also suggested a beneficial effect of PA on macrophage accumulation as well as on oxidative stress. Then, in the 2nd study, we have characterized the functional state of proteins potentially implicated in immune system dysfunctions, and the implication of inflammatory cells in these mechanisms. We have identified a pro-inflammatory cytokine as a key driver of disrupting inflammatory process of plaque. In the same way, we have characterized in the 3rd study, the effect of PA on the monocytic response in atherosclerosis patients, and identified a chemokine associated that could explain the modulation of this monocytic response by PA. Finally, the 4th study demonstrates the hemorheological parameters alteration in carotid artery disease patients, and how PA could limit this alteration via red blood cell aggregation. This PhD thesis provided information regarding regular PA in primary prevention of atherosclerosis. However, additional studies are required to confirm these results, using in particular PA interventional approach