Effects of two weeks detraining on metabolic flexibility in trained older adults

• Autor(a) principal: Lopes, Júlia Matos
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.5/19378
• topic: Physical inactivity; Insulin; Respiratory quotient; Older adults; Metabolic health; Lifestyle; Detraining; Metabolic flexibility; Inatividade física; Insulina; Quociente respiratório; Idosos; Saúde metabólica; Estilo de vida; Destreino; Flexibilidade metabólica; Domínio/Área Científica::Ciências Médicas::Outras Ciências Médicas

Background/Objective: Metabolic flexibility (MF) is highly influenced by lifestyle, in particular by physical activity and diet. However, little attention has been given to the impact of the adoption of sedentary behaviors, physical inactivity and detraining on MF especially in the older adults. Therefore, the aim of this study is to evaluate the effects of a two-week interruption of habitual supervised and structured exercise sessions on MF in trained older adults. Methods: MF was evaluated in 7 older adults (3 females) aged ≥ 65 years (76.9 ± 6.5), before and after the short-term detraining, using indirect calorimetry to analyze the variance in the respiratory quotient (RQ) during the transition from fasting to 100 g oral glucose load. The test had a duration of 2 hours, and to measure the insulin response to the glucose load, blood samples were collected every 60 minutes (i.e. fasting, 60 min, and 120 min). To compare the difference between the moments, a general linear model for repeated measures was used adjusted for the covariates sex and age. Results: There were only differences between the two moments in fasting RQ (P= 0.044). However, there was a trend for all the RQ and insulin mean values being higher after the detraining period. After detraining there was a decrease of 41.7% in RQ variance (P=0.231) and an almost threefold increase in insulin variance (P=0.692). Conclusions: We showed that two weeks did not decrease MF among trained older adults. However, there is a trend to: (1) increase the reliance on carbohydrate as an energy substrate associated with a decrease in fat oxidation, (2) slow the response to the 100 g oral glucose load, (3) reduce RQ variance and increase that for insulin in response to the oral glucose load.