Sono e obesidade
Neste estudo procura-se descobrir como a privação de sono pode levar a obesidade pois estudos observacionais demonstram essa tendência. Ouvimos de diversos profissionais da saúde que menos tempo acordado é mais tempo comendo.Este artigo buscou na literatura deste 1970 ate 2011 evidencias que apoiassem esse fato.
O estudo revelou que a curta duração de sono não afeta substancialmente o gasto energético total diario, nem há evidência suficiente que demonstre qualquer efeito significativo da privação de sono em componentes do metabolismo de energia, como taxa metabólica, atividade fisica, termogenese e utilização de substrato energético.
Somente estudos em ratos mostrou que a total ou grave privação de sono pode afetar o metabolismo ( alteralção em sistemas hormonais e termoregulação), mas estas alterações do sono não são encontradas em pessoas que vivem uma vida livre normal.
Conclue-se então que quando um médico, nutricionista ou qualquer outra pessoa diz que a falta de sono leva a obesidade, diz sem evidência cientifica, diz por repetição do que ouviu de alguém.
de J.-P. Chaput
L. Klingenberg1,†,*, A. Sjödin1, U. Holmbäck2, A. Astrup1, J.-P. Chaput3
Article first published online: 22 MAR 2012
DOI: 10.1111/j.1467-789X.2012.00991.x
Summary
A growing body of observational evidence suggests that short sleep duration is a risk factor for the development of obesity. Although increased energy intake is the most prevailing causal explanation for this association, we should also consider possible effects on energy metabolism to understand fully the potential impact of short sleep duration on the regulation of energy balance. We performed a search of the literature from 1970 to 2011, including original papers, investigating the relation between short sleep and energy metabolism in animals and humans. Although the limited number of experimental studies in humans precludes any definitive conclusions about causality, short sleep duration does not seem to substantially affect total daily energy expenditure, nor is there sufficient evidence in support of any meaningful effect of restricted sleep on the specific components of energy metabolism (i.e. resting metabolic rate, intentional as well as unintentional physical activity, diet-induced thermogenesis, and substrate utilization). As studies on rats suggest that other factors that can potentially influence energy metabolism could be affected (i.e. hormonal systems and thermoregulation), we included these factors in our literature search and found some indications in support of an up-regulation of thyroid hormones and glucocorticoids as well as increased heat dissipation following total or severe sleep deficit. Although we found some evidence also in humans that suggests a possible effect on energy metabolism, the limitations of the studies make it difficult to draw conclusions on the effect of short sleep on energy metabolism under relevant free living conditions. To explore this area further, more studies using suitable methodology under relevant conditions to mimic real-life situations are needed.
http://onlinelibrary.wiley.com/doi/10.1111/j.1467-789X.2012.00991.x/abstract
Klingenberg, L., Sjödin, A., Holmbäck, U., Astrup, A. and Chaput, J.-P. (2012), Short sleep duration and its association with energy metabolism. Obesity Reviews. doi: 10.1111/j.1467-789X.2012.00991.x