The benefits of an active lifestyle are undisputed, yet our understanding of the contribution of physical activity (PA) to the daily energy budget is limited. The prevailing model of a linear relationship between PA and total energy expenditure (TEE) has been challenged by models that predict an upper limit of TEE (constrained) or a compensatory decrease elsewhere in the budget in response to increased PA (compensated). The purpose of this study was to determine the equation of best fit between PA and TEE using linear and non-linear modeling in the light of existing models. Secondarily, we sought to explore relationships between PA and postulated means of behavioral (time sedentary) and physiologic (i.e. Immune, reproductive) compensation. We measured TEE in 57 healthy weight stable adults (18 to 58 yrs., F = 28) who ranged from being sedentary to ultra-endurance trained runners (0 to 78 mi/wk.) using the doubly labeled water technique and PA and sedentary time using a waist mounted triaxial accelerometer during the same 14-day period. We obtained fasting serum (albumin, cortisol, TNFα, C-reactive protein, free testosterone, TSH and T3), plasma (leptin) and whole blood (WBC with differential) concentrations. Using linear and non-linear modeling, we observed a positive linear relationship between PA (Vector Magnitude Counts per Minute ) and TEE (R2=0.313, Y = 1.427*X + 1930 and adjusted for fat free mass (FFM) R2=0.363, Y = 1.151*X + 2155). We identified no association between PA and RMR ( R2=0.015 and adjusted for FFM R2=0.010). In addition, we observed an association between higher PA and lower % time sedentary (R2=0.723). Although inconsistent, there was a general trend for higher PA but not TEE or its components to be associated with lower immune and reproductive biomarkers. These findings support a conventional linear model though intervention studies will be needed to further address this issue. / Doctor of Philosophy / The health benefits of being physically active are well known. At the same time there is much that is not understood about the relationship between physical activity and how much energy we spend in a day (total energy expenditure). It has been assumed for a long time that the amount of energy we spend is a simple matter of adding the calories burned at rest, digesting food, and exercising and as we exercise more we continue to add an equal number of calories to the daily budget. We call this the linear or additive model – energy spent increases in a straight line as physical activity increases. Because we have techniques for measuring total energy expenditure in people going about their usual lives that were not widely available until recently due to cost, scientists have developed new ideas about how increases in physical activity affect total energy expenditure. The constrained model suggests that there is a cap on how many calories we can burn in a day and that our bodies will save energy in other parts of the budget if our physical activity remains high enough to reach or exceed that cap. The second idea is called the compensated model like the constrained model predicts that the rate we spend energy slows down as we exercise more because the body has saved energy in other parts of the budget (compensation). Researchers don't know for sure if either of these models are correct, so we conducted a study to determine how physical activity and total energy expenditure are related and if our findings agree with either of these models. We were also interested in determining how physical activity is related to energy spent at rest (resting metabolic rate ) and energy spent being active (physical activity energy expenditure). Finally, we wanted to determine ways that the body might compensate. One way is to spend more time sedentary. Another way is to save energy on less urgent needs like the immune and reproductive systems. Our main goal was to create an equation that explain how higher levels of physical activity are related to total energy expenditure and other parts of the energy budget (RMR and physical activity energy expenditure). We also created equations that explain how physical activity is related to sedentary behavior and immune and reproductive markers in the blood. We recruited 57 male and female volunteers that represent a wide range of physical activity levels – from sedentary to ultra-endurance trained runners who routinely run as much as 80 miles per week. We measured the energy they spent and physical activity over 2 weeks. In our sample, we found that physical activity was related to total energy expenditure and physical activity energy expenditure in a linear way. We did not find a cap on the amount of energy spent (constraint). We found that participants who exercised more spent less time sedentary not more meaning that we did not find behavioral compensation. It is possible that there was compensation from the immune system because some of the markers of immune function were lower in people who were more physically active, but it was not consistent in all of the blood markers. A larger study using an exercise intervention is needed to assign causation to the correlation we found.

Espera-se que entre 2010 e 2050, a população mundial total terá um aumento de 2 bilhões de habitantes, ao passo que a população idosa chegará ao número de 1,3 bilhões de habitantes. Dentre os diversos fatores envolvidos com expectativa de vida longa, está bem estabelecido que o hábito alimentar desempenha um papel central para a saúde, o que torna importante o conhecimento do padrão alimentar nesta faixa etária. Para a avaliação da ingestão alimentar média a longo prazo em grande número de indivíduos, os Questionários de Frequência de Alimentos (QFAs) são instrumentos particularmente importantes. Objetivo: validar um questionário de frequência alimentar para idosos saudáveis. Casuística e Métodos: Participaram da pesquisa 43 idosos independentes, com a capacidade cognitiva e funcional preservadas, de ambos os gêneros, com idades > 60 anos. Foi avaliado o consumo alimentar dos indivíduos por meio de 3 recordatórios alimentares de 24 horas e um questionário de frequência alimentar, com o auxílio de um livro de fotografias para visualização do tamanho das porções dos alimentos. Como método padrão-ouro, foi utilizada a água duplamente marcada (DLW) para aferição do gasto energético total diário. Para a análise estatística, foi realizada análise descritiva dos dados, calculado o coeficiente de correlação de Spearman, construídos gráficos de dispersão e de Bland-Altman, e também o Coeficiente de Correlação Intraclasse (ICC). Foi adotado o nível de significância de 5%. Resultados: foi observada excelente concordância entre o QFA e DLW para estimativa do consumo de energia em mulheres idosas, assim boa correlação entre o R24h e DLW para estimativa do consumo de energia em homens idosos. Não foram encontradas correlações significativas entre o QFA e DLW para estimativa do consumo de energia em ambos os sexos. Conclusão: Considerando que o objetivo desta pesquisa foi validar o QFA para os dois gêneros (homem e mulher), o mesmo não foi alcançado. / Introduction: It is expected that between 2010 and 2050, the total world population will increase by 2 billion inhabitants, while the elderly population will reach 1.3 billion. Among the many factors involved in long life expectancy, it is well established that eating habits play a central role in health, which makes it important to know the food pattern in this age group. For the evaluation of the long-term average food intake in a large number of individuals, Food Frequency Questionnaires (FFQs) are particularly important instruments. Objective: to validate a food frequency questionnaire for healthy elderly. METHODS: Participants were 43 independent, with cognitive and functional capacity, of both genders, aged> 60 years. The individuals\' food consumption was evaluated through three 24-hour recalls and a food frequency questionnaire, with the aid of a photo book to visualize the size of the food portions. As a gold standard method, double-labeled water (DLW) was used to measure total daily energy expenditure. For the statistical analysis, a descriptive analysis of the data was performed, the Spearman correlation coefficient was calculated, the dispersion and Bland-Altman graphs were constructed, as well as the Intraclass Correlation Coefficient (ICC). The significance level of 5% was adopted. Results: excellent concordance was observed between the QFA and DLW for estimation of energy consumption in elderly women, thus a good correlation between R24h and DLW for estimation of energy consumption in elderly men. No significant correlations were found between the QFA and DLW to estimate the energy consumption in both sexes. Conclusion: Considering that the objective of this research was to validate the FFQ for both genders (man and woman), the same was not achieved.

In the middle of the 1990s many adolescents became vegetarians. There was concern among adults about whether these new young vegetarians got enough energy and nutrients from their dietary intake. The aim of this thesis was to investigate the prevalence of young vegetarians, the food and lifestyle habits, dietary intake and nutritional status of vegetarian and omnivorous adolescents. The prevalence of adolescents eating a vegetarian school lunch in 124 Swedish secondary schools was investigated by interviewing matrons. Information about prevalence of vegetarians, food and lifestyle habits, of 2041 15-year old students from Umeå, Stockholm and Bergen, was obtained by a questionnaire. The dietary intake and nutritional status of thirty 16-20 year-old vegans were compared with thirty age, sex and height matched omnivores. Five percent of the adolescents (16-20 years) in Sweden were found to eat vegetarian food at school lunch. In Umeå there was a significantly higher prevalence (15.6%) of 15-year-old vegetarians compared with Stockholm (4.8%) and Bergen (3.8%). It was also found that more females than males (15 years old) chose a vegetarian dietary regime. Even though the female vegetarians consumed vegetables significantly more often than the omnivores, the intake (32 times/month) was not as often as might be expected of a vegetarian population. The male vegetarians reported eating vegetables not even once a day (25 times/month). No difference in the consumption frequency of fruits/berries, alcoholic beverages, sweets/chocolates and fast foods was seen between vegetarians and omnivores. However, female vegetarians more often than female omnivores consumed dietary supplements. Furthermore, lifestyle characteristics of vegetarians were similar those of omnivores regarding exercise, use of alcohol and smoking habits. No significant difference in validity of reported energy expenditure or energy and protein intakes was found between vegans and omnivores. Young vegans (16-20 year-olds) were seen to have a higher calculated intake of vegetables, legumes, and dietary supplements and a lower intake of ice creams, cakes/cookies, and candies/chocolate than omnivores. The dietary intake was below the average requirements of riboflavin for 73% of the vegans, vitamin B12 for all vegans, vitamin D for 43% of the vegans, calcium for 77% of the vegans and selenium for all vegans and 43% of the omnivores. If intake of supplements was included the intake of e.g. calcium and selenium was still lower than the average requirements for 67% and 73% of the vegans respectively. Low iron stores were as prevalent among vegans as among omnivores (20% and 23% with low stores) and three vegans had low vitamin B12 concentrations in blood. The findings imply that food and lifestyle habits of young vegetarians are different than what previous studies of vegetarians have shown. There is a need for future research of the long-term health effects of being vegetarian.

Espera-se que entre 2010 e 2050, a população mundial total terá um aumento de 2 bilhões de habitantes, ao passo que a população idosa chegará ao número de 1,3 bilhões de habitantes. Dentre os diversos fatores envolvidos com expectativa de vida longa, está bem estabelecido que o hábito alimentar desempenha um papel central para a saúde, o que torna importante o conhecimento do padrão alimentar nesta faixa etária. Para a avaliação da ingestão alimentar média a longo prazo em grande número de indivíduos, os Questionários de Frequência de Alimentos (QFAs) são instrumentos particularmente importantes. Objetivo: validar um questionário de frequência alimentar para idosos saudáveis. Casuística e Métodos: Participaram da pesquisa 43 idosos independentes, com a capacidade cognitiva e funcional preservadas, de ambos os gêneros, com idades > 60 anos. Foi avaliado o consumo alimentar dos indivíduos por meio de 3 recordatórios alimentares de 24 horas e um questionário de frequência alimentar, com o auxílio de um livro de fotografias para visualização do tamanho das porções dos alimentos. Como método padrão-ouro, foi utilizada a água duplamente marcada (DLW) para aferição do gasto energético total diário. Para a análise estatística, foi realizada análise descritiva dos dados, calculado o coeficiente de correlação de Spearman, construídos gráficos de dispersão e de Bland-Altman, e também o Coeficiente de Correlação Intraclasse (ICC). Foi adotado o nível de significância de 5%. Resultados: foi observada excelente concordância entre o QFA e DLW para estimativa do consumo de energia em mulheres idosas, assim boa correlação entre o R24h e DLW para estimativa do consumo de energia em homens idosos. Não foram encontradas correlações significativas entre o QFA e DLW para estimativa do consumo de energia em ambos os sexos. Conclusão: Considerando que o objetivo desta pesquisa foi validar o QFA para os dois gêneros (homem e mulher), o mesmo não foi alcançado. / Introduction: It is expected that between 2010 and 2050, the total world population will increase by 2 billion inhabitants, while the elderly population will reach 1.3 billion. Among the many factors involved in long life expectancy, it is well established that eating habits play a central role in health, which makes it important to know the food pattern in this age group. For the evaluation of the long-term average food intake in a large number of individuals, Food Frequency Questionnaires (FFQs) are particularly important instruments. Objective: to validate a food frequency questionnaire for healthy elderly. METHODS: Participants were 43 independent, with cognitive and functional capacity, of both genders, aged> 60 years. The individuals\' food consumption was evaluated through three 24-hour recalls and a food frequency questionnaire, with the aid of a photo book to visualize the size of the food portions. As a gold standard method, double-labeled water (DLW) was used to measure total daily energy expenditure. For the statistical analysis, a descriptive analysis of the data was performed, the Spearman correlation coefficient was calculated, the dispersion and Bland-Altman graphs were constructed, as well as the Intraclass Correlation Coefficient (ICC). The significance level of 5% was adopted. Results: excellent concordance was observed between the QFA and DLW for estimation of energy consumption in elderly women, thus a good correlation between R24h and DLW for estimation of energy consumption in elderly men. No significant correlations were found between the QFA and DLW to estimate the energy consumption in both sexes. Conclusion: Considering that the objective of this research was to validate the FFQ for both genders (man and woman), the same was not achieved.

O gasto energético total (GET) pode ser usado como medida da ingestão energética (IE). Existe um constante sub-relato da IE obtida por métodos de avaliação do consumo alimentar, mas poucos estudos o investigaram em nações em desenvolvimento. Objetivos: a) comparar a validade das estimativas de IE de um questionário de freqüência alimentar, três recordatórios alimentares e um diário alimentar de três dias, segundo a água duplamente marcada; b) determinar a influência da prática de atividade física, do índice de massa corporal e de fatores psicossociais no sub-relato e; c) comparar as taxas de sub-relato entre agrupamentos de padrões alimentares. Métodos: Sessenta e cinco mulheres responderam aos métodos de inquérito supracitados, a partir dos quais foi estimada a IE. O GET foi medido pela água duplamente marcada. A prática de atividade física, índice de massa corporal, escolaridade, renda, idade, conhecimento nutricional, insatisfação corporal, restrição dietética, compulsão alimentar e o desejo de aceitação social foram correlacionados ao sub-relato. Os padrões alimentares foram obtidos pela análise de cluster. Resultados: O GET foi de 2.622 ± 490 kcal, enquanto que a IE, mensurada respectivamente pelo recordatório, diário e questionário, foi de 2.078 ± 430 kcal; 2.044 ± 479 kcal e 1.984 ± 832 kcal. A proporção de sub-relatores foi de 24,6% para o recordatório, 29,2% para o diário e 53,8% para o questionário (p < 0,005). Os sub-relatores apresentaram menores médias de renda e escolaridade e maiores valores de idade, insatisfação corporal e desejo de aceitação social. O sub-relato foi mais comum no padrão alimentar mais frugal. Conclusão: Os três métodos de avaliação do consumo alimentar apresentaram erros sistemáticos, embora o questionário de freqüência alimentar tenha tido o pior desempenho. O sub-relato foi influenciado por diversos fatores psicossociais e variou conforme o padrão alimentar relatado, o que pode comprometer a avaliação do consumo / Total energy expenditure (TEE) may be used as a measure of energy intake (EI). There is a constant underreporting of EI obtained by dietary assessment methods, but few studies have investigated it in developing nations. Objectives: a) to compare the validity of EI estimates obtained by a food-frequency questionnaire, three diet recalls and a three-day food record; b) to determine the influence of physical activity, body mass index and psychosocial factors on underreporting and; c) to compare underreporting rates between dietary pattern\'s clusters. Methods: Sixty-five women completed the dietary assessment methods, which were used to estimate EI. TEE was measured by doubly labeled water. Physical activity practice, body mass index, education, income, age, nutritional knowledge, body dissatisfaction, dietary restraint, binge eating and social desirability were correlated to underreporting. Dietary patterns were obtained by cluster analysis. Results: TEE was 2,622 ± 490 kcal, while EI, measured respectively by the diet recall, food record and food-frequency questionnaire, was 2,078 ± 430 kcal; 2,044 ± 479 kcal and 1,984 ± 832 kcal. Proportion of underreporters was 24.6% (recall), 29.2% (record) and 53.8% (questionnaire) (p < 0.005). Underreporters had smaller income and education and greater age, body dissatisfaction and social desirability. Underreporting was more common in the \'frugal foods\' pattern. Conclusions: The three dietary assessment methods presented systematic errors, although the foodfrequency questionnaire had the worst performance. Underreporting was influenced by psychosocial factors and varied according the reported dietary pattern, which may compromise dietary assessment

O gasto energético total (GET) pode ser usado como medida da ingestão energética (IE). Existe um constante sub-relato da IE obtida por métodos de avaliação do consumo alimentar, mas poucos estudos o investigaram em nações em desenvolvimento. Objetivos: a) comparar a validade das estimativas de IE de um questionário de freqüência alimentar, três recordatórios alimentares e um diário alimentar de três dias, segundo a água duplamente marcada; b) determinar a influência da prática de atividade física, do índice de massa corporal e de fatores psicossociais no sub-relato e; c) comparar as taxas de sub-relato entre agrupamentos de padrões alimentares. Métodos: Sessenta e cinco mulheres responderam aos métodos de inquérito supracitados, a partir dos quais foi estimada a IE. O GET foi medido pela água duplamente marcada. A prática de atividade física, índice de massa corporal, escolaridade, renda, idade, conhecimento nutricional, insatisfação corporal, restrição dietética, compulsão alimentar e o desejo de aceitação social foram correlacionados ao sub-relato. Os padrões alimentares foram obtidos pela análise de cluster. Resultados: O GET foi de 2.622 ± 490 kcal, enquanto que a IE, mensurada respectivamente pelo recordatório, diário e questionário, foi de 2.078 ± 430 kcal; 2.044 ± 479 kcal e 1.984 ± 832 kcal. A proporção de sub-relatores foi de 24,6% para o recordatório, 29,2% para o diário e 53,8% para o questionário (p < 0,005). Os sub-relatores apresentaram menores médias de renda e escolaridade e maiores valores de idade, insatisfação corporal e desejo de aceitação social. O sub-relato foi mais comum no padrão alimentar mais frugal. Conclusão: Os três métodos de avaliação do consumo alimentar apresentaram erros sistemáticos, embora o questionário de freqüência alimentar tenha tido o pior desempenho. O sub-relato foi influenciado por diversos fatores psicossociais e variou conforme o padrão alimentar relatado, o que pode comprometer a avaliação do consumo / Total energy expenditure (TEE) may be used as a measure of energy intake (EI). There is a constant underreporting of EI obtained by dietary assessment methods, but few studies have investigated it in developing nations. Objectives: a) to compare the validity of EI estimates obtained by a food-frequency questionnaire, three diet recalls and a three-day food record; b) to determine the influence of physical activity, body mass index and psychosocial factors on underreporting and; c) to compare underreporting rates between dietary pattern\'s clusters. Methods: Sixty-five women completed the dietary assessment methods, which were used to estimate EI. TEE was measured by doubly labeled water. Physical activity practice, body mass index, education, income, age, nutritional knowledge, body dissatisfaction, dietary restraint, binge eating and social desirability were correlated to underreporting. Dietary patterns were obtained by cluster analysis. Results: TEE was 2,622 ± 490 kcal, while EI, measured respectively by the diet recall, food record and food-frequency questionnaire, was 2,078 ± 430 kcal; 2,044 ± 479 kcal and 1,984 ± 832 kcal. Proportion of underreporters was 24.6% (recall), 29.2% (record) and 53.8% (questionnaire) (p < 0.005). Underreporters had smaller income and education and greater age, body dissatisfaction and social desirability. Underreporting was more common in the \'frugal foods\' pattern. Conclusions: The three dietary assessment methods presented systematic errors, although the foodfrequency questionnaire had the worst performance. Underreporting was influenced by psychosocial factors and varied according the reported dietary pattern, which may compromise dietary assessment

Introdução: A síndrome do intestino curto (SIC) representa um estado clínico de má absorção grave, e a gestão dietética de pacientes com SIC é extremamente desafiadora. Uma vez que o grau de desnutrição é frequentemente considerável, a intervenção dietética bem sucedida depende da estimativa mais exata possível das necessidades energéticas para prever as metas da terapia nutricional. Objetivo: Quantificar o gasto energético total (GET) em pacientes com SIC pelo método da água duplamente marcada (ADM). Materiais e Métodos: Neste estudo observacional, o GET foi mensurado pelo método da água duplamente marcada em 22 voluntários, 11 com SIC e 11 controles pareados por sexo, idade e IMC (grupo Controle). O GET foi estimado pela equação de Escott-Stump e a partir de acelerômetro, e foi comparado com o GET determinado pela ADM. O gasto energético em repouso (GER) foi mensurado por calorimetria indireta (CI) e comparado com o GER estimado pela equação de Harris e Benedict. O acelerômetro também foi utilizado para estabelecer o nível de atividade física. Resultados: Os participantes tinham idade (média ± DP) de 53 ± 8 anos. O GET medido por ADM foi significativamente menor no grupo SIC comparado ao grupo Controle (p < 0,01); no entanto, o GET estimado não diferiu significativamente entre os grupos. O GET medido foi significativamente maior do que o GET estimado por fórmula no grupo SIC, (respectivamente 1875 ± 276 e 1517 ± 175 kcal/dia, p < 0,01), assim como para o grupo Controle (2393 ± 445 e 1532 ± 178 kcal/dia, p < 0,01). No entanto, o GET medido foi significativamente menor do que o GET predito a partir do acelerômetro no grupo SIC (2075 ± 298 kcal/dia, p = 0,02), e não diferiu significativamente no grupo Controle (2207 ± 355 kcal/dia, p = 0,21). Não foram verificadas diferenças significantes entre o GER medido e predito para ambos, e entre os grupos. Conclusão: O GET medido em pacientes com SIC foi significativamente maior do que o GET estimado por fórmula, e foi menor quando comparado com os valores dos sujeitos controles. No entanto, o GET estimado a partir do acelerômetro, superestima o GET medido por ADM. As fórmulas atualmente utilizadas na prática clínica parecem subestimar as necessidades de energia de pacientes com SIC. Desta forma, adaptações da estimativa atual, aumentando as prescrições de ingestão energética nestes pacientes parecem ser adequadas para apoiar as necessidades diárias de energia e evitar a subnutrição. / Background: Short bowel syndrome (SBS) is a serious malabsorption disorder, and dietetic management of SBS patients is extremely challenging. Once the degree of undernutrition has been assessed, successful dietary intervention depends on the most accurate estimation and provision of energy needs to provide nutritional therapy goals. Objective: To quantify total energy expenditure (TEE) in SBS patients using the doubly labeled water (DLW) method. Design: In this observational study, TEE was measured by the DLW method in 22 participants, 11 with SBS and 11 gender-age-and BMI-matched controls (Control group). Predicted energy requirements were determined using the Escott-Stump equation and by using and accelerometer, and they were compared with TEE determined with DLW. Resting energy expenditure (REE) was measured using indirect calorimetry and compared with predict REE using the Harris and Benedict equation. The accelerometer was also used to determine physical activity level. Results: Participants were aged (mean ± SD) 53 ± 8 years. Measured TEE was significantly lower in the SBS group compared to the Control group (p < 0.01); however, predicted TEE did not differ significantly between the groups. Measured TEE was significantly higher than predicted TEE for the SBS group, (1875 ± 276 and 1517 ± 175 kcal/d, p < 0.01) and also for the Control group (2393 ± 445 and 1532 ± 178 kcal/d, p < 0.01) when determined by formula. However, measured TEE was significantly lower than predicted TEE (2075 ± 298 kcal/d, p = 0.02) for the SBS group, and did not differ for the Control group (2207 ± 355 kcal/d, p = 0.21) when determined by accelerometer. No significant differences were seen between measured and predicted REE both within and between groups. Conclusion: Measured TEE in SBS patients was significantly higher than predicted using standard equations, but also lower than values for age, BMI and gender-matched non-SBS controls. However, predicted TEE using accelerometer overestimated the measured TEE. Currently-used formulas in clinical practice appear to underestimate energy requirements of SBS patients. Therefore, adjustments to the current estimation, increasing the energy intake requirements in these patients appear to be adequate to support the daily energy requirements and avoid undernutrition.

Une mesure précise de l’activité physique en conditions de vie libre est nécessaire pour une meilleure compréhension de ses relations avec la santé. Le premier objectif de ce travail thèse a été de valider l’Actiheart (qui combine la mesure de la fréquence cardiaque et du mouvement par accélérométrie) par rapport à l’eau doublement marquée (EDM). Nous montrons un bon niveau de concordance entre la dépense énergétique liée à l’activité physique (DEAP) estimée par l’Actiheart et l’EDM. Une individualisation de la relation entre la fréquence cardiaque et de la DEAP par un test d’effort est nécessaire pour une estimation fiable de la DEAP au niveau individuel et pour évaluer des changements de DEAP tels qu’induits par une intervention. En laboratoire, nous montrons que la précision de l’Actiheart est activité dépendante. Ceci nécessite la mise en place de leur reconnaissance par de nouveaux capteurs et modèles mathématiques. L’adiponectine est une hormone du tissu adipeux qui a un rôle dans le métabolisme énergétique et dont la sécrétion diminue avec l’obésité. Les effets de l’activité physique sont en revanche contradictoires dans la littérature. Le second objectif de ce travail a été d’évaluer l’effet de l’activité physique et d’une intervention avec contrôle du poids sur les taux plasmatiques d’adiponectine. Nous montrons que l’adiponectine totale et à haut poids moléculaire sont associées négativement à la variation du niveau d’activité physique. D’autres travaux sont cependant nécessaires pour comprendre les mécanismes qui sous-tendent cette modulation de l’adiponectine plasmatique qui ne semble pas liée à des variations de synthèse dans le tissu adipeux ou musculaire. / Accurate measurements of physical activity in free living are needed to establish what dose of physical activity is necessary for obtaining a specific health benefits. The first aim of this work was to validate the Actiheart (which combines heart rate and accelerometry sensors) with doubly labeled water (DLW). We show a good level of concordance between physical activity energy expenditure (PAEE) estimated by Actiheart and DLW. Individualization of the relationship between heart rate and PAEE by an incremental test is needed for an accurate estimate of the PAEE at the individual level and to evaluate changes induced by an intervention. In laboratory, we show that the accuracy of Actiheart is activitydependent. This requires the establishment of their recognition from new sensors and mathematical models. Adiponectin, hormone secreted by adipose tissue, has a role in energy metabolism and its secretion decreases with obesity. However the effects of physical activity remain in contradiction in published studies. The second objective of this work was to evaluate the effect of physical activity and intervention with weight control on plasma adiponectin. We show that the total and high molecular weight adiponectin were negatively associated with modifications of the physical activity level. Further work is however necessary to understand the mechanisms underlying this modulation of plasma adiponectin which does not seem related to changes in synthesis in adipose tissue or muscle.

Introdução: A síndrome do intestino curto (SIC) representa um estado clínico de má absorção grave, e a gestão dietética de pacientes com SIC é extremamente desafiadora. Uma vez que o grau de desnutrição é frequentemente considerável, a intervenção dietética bem sucedida depende da estimativa mais exata possível das necessidades energéticas para prever as metas da terapia nutricional. Objetivo: Quantificar o gasto energético total (GET) em pacientes com SIC pelo método da água duplamente marcada (ADM). Materiais e Métodos: Neste estudo observacional, o GET foi mensurado pelo método da água duplamente marcada em 22 voluntários, 11 com SIC e 11 controles pareados por sexo, idade e IMC (grupo Controle). O GET foi estimado pela equação de Escott-Stump e a partir de acelerômetro, e foi comparado com o GET determinado pela ADM. O gasto energético em repouso (GER) foi mensurado por calorimetria indireta (CI) e comparado com o GER estimado pela equação de Harris e Benedict. O acelerômetro também foi utilizado para estabelecer o nível de atividade física. Resultados: Os participantes tinham idade (média ± DP) de 53 ± 8 anos. O GET medido por ADM foi significativamente menor no grupo SIC comparado ao grupo Controle (p < 0,01); no entanto, o GET estimado não diferiu significativamente entre os grupos. O GET medido foi significativamente maior do que o GET estimado por fórmula no grupo SIC, (respectivamente 1875 ± 276 e 1517 ± 175 kcal/dia, p < 0,01), assim como para o grupo Controle (2393 ± 445 e 1532 ± 178 kcal/dia, p < 0,01). No entanto, o GET medido foi significativamente menor do que o GET predito a partir do acelerômetro no grupo SIC (2075 ± 298 kcal/dia, p = 0,02), e não diferiu significativamente no grupo Controle (2207 ± 355 kcal/dia, p = 0,21). Não foram verificadas diferenças significantes entre o GER medido e predito para ambos, e entre os grupos. Conclusão: O GET medido em pacientes com SIC foi significativamente maior do que o GET estimado por fórmula, e foi menor quando comparado com os valores dos sujeitos controles. No entanto, o GET estimado a partir do acelerômetro, superestima o GET medido por ADM. As fórmulas atualmente utilizadas na prática clínica parecem subestimar as necessidades de energia de pacientes com SIC. Desta forma, adaptações da estimativa atual, aumentando as prescrições de ingestão energética nestes pacientes parecem ser adequadas para apoiar as necessidades diárias de energia e evitar a subnutrição. / Background: Short bowel syndrome (SBS) is a serious malabsorption disorder, and dietetic management of SBS patients is extremely challenging. Once the degree of undernutrition has been assessed, successful dietary intervention depends on the most accurate estimation and provision of energy needs to provide nutritional therapy goals. Objective: To quantify total energy expenditure (TEE) in SBS patients using the doubly labeled water (DLW) method. Design: In this observational study, TEE was measured by the DLW method in 22 participants, 11 with SBS and 11 gender-age-and BMI-matched controls (Control group). Predicted energy requirements were determined using the Escott-Stump equation and by using and accelerometer, and they were compared with TEE determined with DLW. Resting energy expenditure (REE) was measured using indirect calorimetry and compared with predict REE using the Harris and Benedict equation. The accelerometer was also used to determine physical activity level. Results: Participants were aged (mean ± SD) 53 ± 8 years. Measured TEE was significantly lower in the SBS group compared to the Control group (p < 0.01); however, predicted TEE did not differ significantly between the groups. Measured TEE was significantly higher than predicted TEE for the SBS group, (1875 ± 276 and 1517 ± 175 kcal/d, p < 0.01) and also for the Control group (2393 ± 445 and 1532 ± 178 kcal/d, p < 0.01) when determined by formula. However, measured TEE was significantly lower than predicted TEE (2075 ± 298 kcal/d, p = 0.02) for the SBS group, and did not differ for the Control group (2207 ± 355 kcal/d, p = 0.21) when determined by accelerometer. No significant differences were seen between measured and predicted REE both within and between groups. Conclusion: Measured TEE in SBS patients was significantly higher than predicted using standard equations, but also lower than values for age, BMI and gender-matched non-SBS controls. However, predicted TEE using accelerometer overestimated the measured TEE. Currently-used formulas in clinical practice appear to underestimate energy requirements of SBS patients. Therefore, adjustments to the current estimation, increasing the energy intake requirements in these patients appear to be adequate to support the daily energy requirements and avoid undernutrition.

L’objectif de cette étude est de déterminer certains paramètres respiratoires et cardiovasculaires chez des sujets de tous âges pour utilisation, à titre d’intrants physiologiques, en modélisation toxicocinétique et en analyse du risque toxique. La base de données utilisée est tirée de la littérature. Il s’agit de mesures portant sur la dépense d’énergie quotidienne de base et la dépense d’énergie quotidienne de totale obtenues, l’une par calorimétrie indirecte, l’autre par double marquage isotopique des molécules d’eau. Selon le type d’unité retenu, les valeurs les plus élevées au 99e centile des taux quotidiens d’inhalation sont obtenues chez des adolescentes et des femmes âgées de 11 à 55 ans souffrant d’embonpoint ou d’obésité, durant leur 36e semaine de grossesse (47,31 m³/jour), ainsi que chez des garçons de poids corporel normal âgés de 2,6 à moins de 6 mois (1,138 m³/kg-jour) et de 10 à moins de 16,5 ans (22,29 m³/m²-jour). Chez les enfants et les adolescents de poids corporel normal âgés de 5 à moins de 16.5 ans, les valeurs pour l’écart entre le 2,5e au 99e centile sont généralement plus élevées que celles obtenues chez les sujets plus âgés : taux de ventilation minute, 0,132 à 0,774 L/kg-min ou 4,42 à 21,69 L/m²-min versus 0,076 à 0,461 L/kg-min ou 2,80 à 16,99 L/m²-min; taux de ventilation alvéolaire, 0,093 à 0,553 L/kg-min ou 3,09 à 15,53 L/m²-min versus 0,047 à 0,312 L/kg-min ou 1,73 à 11,63 L/m²-min; débit cardiaque, 0,065 à 0,330 L/kg-min ou 2,17 à 9,46 L/m²-min versus 0,045 à 0,201 L/kg-min ou 1,63 à 7,24 L/m²-min; ratio de ventilation-perfusion, 1,12 à 2,16 versus 0,78 à 2,40. Il faut conclure que les apports inhalés en polluants, exprimés en ug/kg-min ou ug/m²-min sont plus élevés chez les enfants que chez les sujets plus âgés pour des concentrations d’exposition comparables. D’autres données montrent qu’il en est de même pour les apports inhalés par unité de poids corporel chez les femmes enceintes et les femmes qui allaitent par rapport à des sujets males d’âge comparable. L’ensemble des résultats obtenus suggère notamment que les valeurs des NOAELH de Santé Canada pourraient être abaissées par un facteur de 2,6 par utilisation du 99e centile le plus élevé des taux quotidiens d’inhalation chez les enfants; le taux de ventilation minute de 20,83 L/min approximé pour une journée de travail de 8 heures peut être considéré comme étant conservateur ; par contre, l’utilisation du taux quotidien d’inhalation de 0,286 m³/kg-jour (c.-à-d. 20 m³/jour pour un adulte de poids corporel de 70 kg) est inappropriée en analyse et gestion du risque lorsqu’appliquée à l’ensemble de la population. / The aim of the present study is to determine some respiratory and cardiovascular parameters in subjects of all ages for use, as physiological inputs, in toxicokinetic simulations and toxic risk assessment. The database used is taken from the literature. Data of interest include basal energy expenditures and total daily energy expenditures obtained by indirect calorimetry and doubly labeled water measurements respectively. Depending upon the unit value chosen, the highest 99th percentiles for daily inhalation rates were found in overweight/obese females 11 to 55 years old during their 36th weeks of pregnancy (47.31 m³/day), as well as in normal-weight boys aged 2.6 to less than 6 months(1.138 m³/kg-day) and 10 to less than 16.5 years (22.29 m³/m²-day). Generally higher values for the 2.5th up to 99th percentile were found in normal-weight children and teenagers aged 5 to less than 16.5 years compared to those for older individuals: minute ventilation rate, 0.132 to 0.774 L/kg-min or 4.42 to 21.69 L/m²-min versus 0.076 to 0.461 L/kg-min or 2.80 to 16.99 L/m²-min; alveolar ventilation rate, 0.093 to 0.553 L/kg-min or 3.09 to 15.53 L/m²-min versus 0.047 to 0.312 L/kg-min or 1.73 to 11.63 L/m²-min; cardiac output, 0.065 to 0.330 L/kg-min or 2.17 to 9.46 L/m²-min versus 0.045 to 0.201 L/kg-min or 1.63 to 7.24 L/m²-min; ventilation-perfusion ratio, 1.12 to 2.16 versus 0.78 to 2.40. Higher intakes of air pollutants by the respiratory tract expressed in ug/kg-min or ug/m²-min are expected in children compared to older individuals for identical exposure concentrations.The same conclusion is reached in pregnant and lactating females compared to male subjects of same ages, for intakes expressed per unit of bodyweight. The aggregate results obtained notably suggests that NOAELH values from Health Canada could be decreased by a factor of 2.6 by the use of the highest 99th percentiles for daily inhalation rates found in children; the minute ventilation rate of 20.83 L/min approximated based on an 8-hour workday may be considered as being conservative; however, the use of the daily inhalation rate of 0.286 m³/kg-day (i.e. 20 m³/day for a 70-kg adult) is inappropriate in risk assessment and management when applied to the whole population.