EXERCISE SUBSTRATE UTILIZATION--THE CROSSOVER CONCEPT

描述(改编自申请人的摘要)：总体目标 就是找出并理解控制平衡的因素 来自内源性碳水化合物和脂肪的能量在持续、 次极量运动。理论基础是交叉概念，即 在空腹状态下的休息和轻度至中度运动期间，血脂 提供最大比例的能量。随着强度从 中等到困难到最大，即使在训练状态下也是如此 底物的利用从脂肪转变为碳水化合物。该项目将 描述了饮食历史、运动强度和 训练状态影响底物利用的平衡。还有，因为 相比较而言，血糖和游离脂肪酸的容量有限。 由于运动期间维持的流量，这些池在运动期间的调节 练习将被描述。该项目的目标是(1)描述 营养状况、训练状况和锻炼的交互作用 运动过程中糖异生的强度；2)评估假说 肌肉线粒体对脂肪酸的摄取限制了脂质氧化 以及3)评估月经周期对 利用脂类能源的能力。为了实现这些目标，人们和 将研究女性在休息和锻炼过程中的绝对运动和 训练前后的相对强度。对女性来说，这种影响 月经周期各期对底物利用的平衡 下定决心。在男性中，耐力训练、乳酸、二氯乙酸酯和 肝素加Intralipid输液将用于解剖耐药部位 存在于运动期间的底物供应中。间接量热法 启动-连续双稳定同位素输注、同位素和同位素异构体 分析和糖调节激素分析将被用来解决 明确的目标。

DESCRIPTION (Adapted from the applicant's abstract): The overall objective is to identify and understand the factors which control the balance of energy derived from endogenous carbohydrate and lipids during sustained, submaximal exercise. The theoretical basis is the crossover concept that during rest and mild to moderate exercise in the fasted state, lipids provide the greatest proportion of energy. As the intensity increases from moderate to hard to maximal, even in the trained state the balance of substrate utilization switches from lipid to carbohydrate. The project will delineate mechanisms by which dietary history, exercise intensity, and training state affect the balance of substrate utilization. Also, because blood glucose and free fatty acid pools are limited in capacity compared with the fluxes sustained during exercise, regulation of these pools during exercise will be described. The aims of the project are (1) to describe the interactive effects of nutritional status, training status, and exercise intensity on gluconeogenesis during exercise; 2) evaluate the hypothesis that muscle mitochondrial uptake of fatty acids limits lipid oxidation during exercise, and 3) evaluate the effects of the menstrual cycle on the capacity to utilize lipid energy sources. To address these aims, men and women will be studied at rest and during exercise of given absolute and relative intensities, both before and after training. In women, the effects of menstrual cycle phase on the balance of substrate utilization will be determined. In men, endurance training, lactate, dichloroacetate, and heparin plus Intralipid infusion will be used to dissect where resistances exist in substrate supply during exercise. Indirect calorimetry, primed-continuous dual stable isotope infusion, isotope and isotopomer analyses, and glucoregulatory hormonal analyses will be used to address the specific aims.