The effects of breaking up sedentary behaviors on energy and substrate metabolism

项目总结/摘要 尽管众所周知的运动对健康有益，但大多数成年人并不符合体力活动（PA） 建议，代谢性疾病的患病率继续上升。传统上，PA通常是 处方为每天30-60分钟的单次连续发作。新发布的PA指南不再要求 PA为10分钟的发作，并建议减少久坐行为（SB）。这很重要因为 流行病学和实验证据表明，打破SB（即坐）与短期频繁的发作， PA急剧下降，即使在经常锻炼的人。然而，无论急性 在实验室外，中断长时间坐着的代谢效应会随着时间的推移而持续， 潜在的生物学机制仍然知之甚少。我的论文旨在解决这些问题 久坐不动、缺乏体力活动的超重至肥胖成年人的问题。我的初步数据 论文认为，打破SB与短期频繁PA发作蔓延整个一天急剧 在24小时内和餐后增加了对碳水化合物作为燃料的依赖，这可以解释减少的原因。 在许多研究中观察到的日常生活中。这个F31奖项的目的是调查持续的 在超重至肥胖、久坐不动、身体不适、 不活动的成年人血糖控制和潜在的潜在机制（即24小时和餐后饮食和 总碳水化合物氧化），并比较与总活动时间匹配的干预措施诱导的效果 但由每天一次连续的PA组成。PA的好处在一天中传播开来， 与单次连续PA的每日表现相比， 全身胰岛素敏感性，但更多地使用碳水化合物作为燃料。在短暂的活动中， 来自糖原储存的碳水化合物可能是主要的能量来源，然后通过增加 骨骼肌对血糖的摄取。随着时间的推移，这种影响在最后一轮之后持续了几个小时。 降低餐后血糖和每日血糖波动的活性，沿着更高的氧化速率 总碳水化合物和膳食碳水化合物的含量，即使在个人休息时。拟议的研究将提供初步的 证据基础的健康益处打破长期坐着与短时间的活动，和关键 为今后的机制研究提供信息。这个F31奖项进一步概述了职业发展计划， 补充我的博士培训集中在PA的代谢影响，以促进临床研究培训， 利用稳定同位素示踪法跟踪底物代谢，双标记水法， 得出每日总能量消耗，使用基于加速度计的监测器来评估SB的日常模式 以及PA和连续葡萄糖监测，以评估每日葡萄糖波动。这一培训还将加强 我的学术活动，评价我的研究，批判性思维和自主权的能力，这将有助于我确保 PA和肥胖/糖尿病管理研究领域的博士后职位。

PROJECT SUMMARY/ABSTRACT Despite the well-known health benefits of exercise, most adults do not meet physical activity (PA) recommendations, and the prevalence of metabolic diseases continues to rise. Traditionally, PA is typically prescribed as a single-continuous bout of 30-60 min per day. The newly released PA guidelines no longer require PA to be in 10-min bouts and suggest reducing sedentary behaviors (SB). This is important because epidemiologic and experimental evidence suggest that breaking up SB (i.e. sitting) with short-frequent bouts of PA acutely decreased glycemia, even in individuals who exercise regularly. However, whether the acute metabolic effects of interrupting prolonged sitting are sustained over time and outside the laboratory and potential underlying biological mechanisms remain poorly understood. My dissertation aims to address these questions in sedentary, physically inactive adults with overweight to obesity. The preliminary data from my dissertation suggest that breaking up SB with short-frequent PA bouts spread throughout the day acutely increases the reliance on carbohydrate as fuel over 24h and following a meal, which may explain the decrease in daily glycemia observed in numerous studies. The objective of this F31 award is to investigate the sustained (4-week) effect of breaking up SB with short-frequent bouts of PA in overweight to obese, sedentary, physically inactive adults on glycemic control and potential underlying mechanisms (i.e. 24h and postprandial dietary and total carbohydrate oxidation), and to compare the effects induced by an intervention matched for total active time but consisting of a daily-single continuous bout of PA. The benefits of the PA spread throughout the day on glycemia compared to the daily performance of a single-continuous bout of PA is likely not due to differences in whole-body insulin sensitivity but to a greater use of carbohydrate as fuel. During the short bouts of activity, carbohydrate from glycogen stores is likely the primary energy source and then replenished by increasing skeletal muscle uptake of plasma glucose. Over time, this effect is lasting several hours after the last bout of activity which decreases postprandial glycemia and daily glucose excursions, along with greater oxidative rates of total and dietary carbohydrate even when individuals are resting. The proposed studies will provide an initial evidence base for the health benefits of breaking up prolonged sitting with short bouts of activity, and key information for future mechanistic studies. This F31 award further outlines a career development plan to supplement my doctoral training focused on the metabolic effects of PA to facilitate clinical research training in the use of stable isotope tracer methodology to track substrate metabolism, doubly labelled water method to derive total daily energy expenditure, use of accelerometry-based monitors to assess the daily patterns of SB and PA and continuous glucose monitoring to assess daily glucose excursions. This training will also strengthen my scholarly activities, ability to valorize my research, critical thinking and autonomy that will help me in securing a post-doctoral position in the research field of PA and obesity/diabetes management.