Qualidade do sono, atividade física e funcionamento físico de pessoas idosas independentes

O objetivo deste estudo foi analisar associações entre a qualidade do sono, a atividade física e o funcionamento físico (aptidão física e atividades da vida diária (AVD)) de pessoas idosas independentes. Metodologia: A amostra incluiu 437 pessoas idosas independentes (143 homens e 294 mulheres; 65-103 anos). A qualidade do sono e as AVD foram avaliadas através de questionário, a atividade física através de acelerometria e a aptidão física através do Senior Fitness Test. Resultados: A análise da regressão logística tendo como variável dependente a qualidade do sono e como variáveis independentes a atividade física, a aptidão física e as AVD, revelou que as AVD foi a única variável explicativa da discriminação entre má e boa qualidade do sono. O aumento de um ponto nas AVD correspondeu a uma diminuição de 91,4% na probabilidade de ter uma má qualidade de sono. Os resultados não foram alterados quando se incluiu no modelo o género, a idade ou o escalão etário. Conclusões: Um melhor funcionamento físico parece estar associado a uma melhor qualidade do sono em pessoas idosas. A obtenção de 19 pontos nas AVD revelou ser discriminatória da qualidade do sono de pessoas idosas.

Patterns of sedentary behavior : insights from observational and experimental studies on body composition and energy expenditure

It is recognized that sedentary behavior (SB) has deleterious effects on numerous health outcomes and it appears that physiological mechanisms underlying these harms are distinct from the ones explaining moderate-to-vigorous physical activity (MVPA) benefits. Sedentary behavior represents a large portion of human’s life and is increasing with technological development. A new current of opinion supports the idea that the manner SB is accumulated plays an important role. This dissertation presents six research studies conducted under the scope of SB. In the methodological area, the first study highlighted the magnitude of potential errors in estimating SB and its patterns from common alternative methods (accelerometer and heart rate monitor) compared to ActivPAL. This study presented the accelerometer as a valid method at a group level. Two studies (2 and 5) were performed in older adults (the most sedentary group in the population) to test the associations for SB patterns with abdominal obesity using accelerometry. The findings showed positive graded associations for prolonged sedentary bouts with abdominal obesity and showed that those who interrupted SB more frequently were less likely to present abdominal obesity. Therefore, public health recommendations regarding breaking up SB more often are expected to be relevant. The associations between sedentary patterns and abdominal obesity were independent of MVPA in older adults. However, the low MVPA in this group makes it unclear whether this independent relationship still exists if highly active persons are analysed. Study 3 inovates by examining the association of SB with body fatness in highly trained athletes and found SB to predict total fat mass and trunk fat mass, independently of age and weekly training time. Study 4 also brings novelty to this research field by quantifying the metabolic and energetic cost of the transition from sitting to standing and then sitting back down (a break), informing about the modest energetic costs (0.32 kcal·min−1). Finally, from a successful multicomponent pilot intervention to reduce and break up SB (study 6), an important behavioral resistance to make more sit/stand transitions despite successfully reducing sitting time (~ 1.85 hours·day-1) was found, which may be relevant to inform future behavioral modification programs. The present work provides observational and experimental evidence on the relation for SB patterns with body composition outcomes and energy regulation that may be relevant for public health interventions.