Postprandial glucose responses in trained older adults : effects of breaking of up sedentary time and 2 weeks detraining

• Autor(a) principal: Correia, Inês Ribeiro dos Ramos
• 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/10400.5/19394
• topic: Sitting time; Physical inactivity; Breaks; Glycemic control; Continuous glucose monitoring; older adults; Tempo sentado; Inatividade física; Interrupções; Controlo glicémico; Monitorização contínua da glicémia; Idosos; Domínio/Área Científica::Ciências Médicas::Outras Ciências Médicas

Regularly interrupting sedentary behavior (SB) with activity breaks may attenuate postprandial glucose (PPG) excursions and improve glycemic control. Purpose: We aimed to determine the effect of interrupting 7 hours of prolonged sitting with brief bouts of moderate physical activity (PA) (alternating between up/down stairs and sit/stand up from the chair) on postprandial glucose (PPG) responses in comparison with uninterrupted sitting. In addition, we aimed to study the effects of 2 weeks of detraining (DT) on PPG on both protocols. Methods: Non-diabetic, trained older adults (n = 9; 5 males), aged 77.0±5.8 years, were recruited for a randomized crossover trial with two treatments performed in two different training conditions: 1) uninterrupted sitting protocol (CON); 2) seated with 2-minutes bouts of moderate PA every 30 minutes (INT). Both protocols were performed in a trained condition and after 2 weeks of DT. In the early morning of each trial, participants did an oral glucose tolerance test (OGTT) and 2 blood samples were collected (fasting and after 2 hours); 2.5 hours after, participants began the protocol and two standardized meals were provided (0 hours and at 3 hours). An iPro2 continuous glucose monitoring (CGM) system recorded the average interstitial glucose concentration every 5 minutes. Positive incremental area under the curve (iAUC) and total area under the curve (pAUC) for glucose as well as mean glucose (MG) were calculated using Matlab. Differences between both protocols and between the two different moments were examined using generalized estimation equation (GEE), adjusting for sex and age (CI 95%). Results: No differences were found between CON and INT protocols at baseline (tAUC: 40.8±7.0 mmol/l/h vs. 39.9±8.2 mmol/l/h, Δ -2.2%, p = 0.772; iAUC: 6.7±3.6 mmol/l/h vs. 5.3±4.0 mmol/l/h, Δ -20.9%, p = 0.390; MG: 5.9±0.9 mmol/l vs. 5.8±1.2 mmol/l, Δ -1.7 %, p = 0.719), neither in post-detraining period (tAUC: 46.2±7.2 mmol/l/h vs. 43.3±10.8 mmol/l/h, Δ -6.3%, p = 0.495; iAUC: 9.6±4.8 mmol/l/h vs. 8.1±9.1 mmol/l/h, Δ -15.6%, p = 0.646; MG: 6.7±1.0 mmol/l vs. 6.3±1.6 mmol/l, Δ -6.0%, p = 0.515). Moreover, no differences were found when baseline and post-detraining moments were compared (tAUC: CON, Δ 13.2%, p = 0.055; INT, Δ 8.5%, p = 0.401; iAUC: CON, Δ 43.3%, p = 0.100; INT, Δ 52.8%, p = 0.343; MG: CON, Δ 13.6%, p = 0.056; INT, Δ 8.6%, p = 0.390). Conclusions: Although considerable percentage differences were observed in glucose responses in the two protocols and in the two moments of evaluation (trained and after 2-week detraining), according to the sample size and after statistical tests brief interruptions of sedentary time (ST) of moderate-intensity PA does not seem to acutely modify PPG response in trained older adults. Also, 2 weeks of DT were not sufficient to promote changes in PPG.