EXERCISE SUBSTRATE UTILIZATION--THE CROSSOVER CONCEPT

描述（改编自申请人的摘要）：总体目标 是识别和理解控制平衡的因素， 能量来源于内源性碳水化合物和脂质， 次极量运动 理论基础是交叉概念， 在禁食状态下休息和轻度至中度运动期间， 提供最大比例的能量。 随着强度从 即使在训练状态下， 底物利用从脂质转变为碳水化合物。 该项目将 描述饮食史、运动强度和 培养状态影响基质利用的平衡。 也因为 血糖和游离脂肪酸池的容量有限， 随着运动过程中持续的通量， 练习将被描述。 该项目的目的是（1）描述 营养状况、训练状况和运动的交互作用 强度对运动过程中骨骼肌再生的影响; 2）评估假设 肌肉线粒体对脂肪酸的摄取限制了脂质氧化 在运动过程中，和3）评估月经周期的影响， 利用脂质能源的能力。 为了实现这些目标， 将研究妇女在休息和行使给定的绝对和 训练前后的相对强度。 在女性中， 月经周期阶段对底物利用的平衡将是 测定 在男性，耐力训练，乳酸，二氯醋酸， 将使用肝素加胰岛素输注来剥离耐药部位 存在于运动过程中的基质供应中。 间接量热法， 预充-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用于解决 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.