EXERCISE SUBSTRATE UTILIZATION--THE CROSSOVER CONCEPT

运动基质的利用——交叉概念

• 批准号: 2082439
• 负责人: GEORGE Austin BROOKS
• 金额: $ 31.06万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-07-15 至 1997-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2082439
• 关键词: EXERCISE; SUBSTRATE; UTILIZATION; CROSSOVER; CONCEPT

Our overall objective is to identify and understand the factors which control the balance of energy derived from endogenous carbohydrate (CHO) and lipid utilization during sustained, submaximal exercise. The theoretical basis of our approach is the "crossover" concept which we develop fully in our text. Simply put, we believe that during rest and mild to moderate intensity exercise, lipids provide the greatest proportion of energy for exercise. However, as the exercise increases from moderate to hard to maximal, the balance of substrate utilization switches, or 'crosses over' from lipid to carbohydrate. The "Crossover Point" is identified as the power output at which carbohydrate-derived fuels predominate over lipids as energy sources with further increases in power eliciting proportional increments in carbohydrate utilization and decrements in lipid utilization. We further believe that while prior exercise (endurance training) enhances the ability to utilize lipids during mild to moderate intensity exercise, crossover to carbohydrate dependence inevitably occurs in the transition from moderate intensity to hard exercise, crossover to carbohydrate dependence inevitably occurs in the transition from moderate intensity to hard exercise, even in the trained state. In pursuit of our overall objective, we propose to explore five specific aims. These are to: (1) describe the effects of exercise intensity on the balance of energy derived from glucose and free fatty acid (FFA) utilization, (2) described the effects of endurance training on this balance, (3) explore the role of the sympathetic nervous system (SNS), specifically epinephrine, in controlling this balance during exercise, (4) evaluate the role of lactate as a metabolic intermediate, and (5) evaluate the possibility that women may differ from men in their metabolic response to exercise and exercise training. To address these aims, we propose to study men and women at rest and during exercises of give absolute and relative intensities, both before and after long-term training. On men, we plan to also to utilize short- term endurance training, as well as beta-adrenergic blockade in an attempt to dissect sympathetic from other training-induced adaptations on the balance of substrate supply during exercise. Techniques of indirect calorimetry, primed-continuous stable isotope infusion, muscle biopsies and measurements of leg arterial-venous difference [(a-v)] and blood flow as well as response of glucoregulatory hormones will be used to address the above indicated specific aims.

我们的总体目标是识别和理解影响因素 控制内源性碳水化合物 (CHO) 的能量平衡 以及持续、次最大运动期间的脂质利用。 这 我们方法的理论基础是“交叉”概念 在我们的文本中得到充分发展。 简而言之，我们相信在休息和 轻度到中度强度的运动，血脂提供最大的 用于运动的能量比例。 但随着运动量的增加 从中等到困难到最大，底物利用率的平衡 从脂质转换或“交叉”到碳水化合物。 “跨界 点”被确定为碳水化合物衍生的功率输出 燃料作为能源的地位超过脂类且进一步增加 功率引起碳水化合物利用率成比例增加 以及脂质利用的减少。 我们进一步相信，虽然之前 运动（耐力训练）增强利用脂质的能力 在轻度至中度强度运动期间，交叉使用碳水化合物 从中等强度过渡时不可避免地会出现依赖性 到剧烈运动，不可避免地会发生对碳水化合物的依赖 从中等强度运动过渡到高强度运动时，即使在 受过训练的状态。 为了实现我们的总体目标，我们建议探索五个具体目标 目标。 这些是：（1）描述运动强度对 来自葡萄糖和游离脂肪酸 (FFA) 的能量平衡 利用，（2）描述了耐力训练对此的影响 平衡，（3）探索交感神经系统（SNS）的作用， 特别是肾上腺素，在运动过程中控制这种平衡， (4) 评估乳酸作为代谢中间体的作用，以及 (5) 评估女性在其行为方面可能与男性不同的可能性 对运动和运动训练的代谢反应。 为了实现这些目标，我们建议研究休息和休息时的男性和女性 在练习中给予绝对和相对强度，之前 并且经过长期的训练。 对于男性，我们还计划利用短 长期耐力训练以及β-肾上腺素能阻断 尝试将交感神经与其他训练引起的适应进行剖析 运动期间底物供应的平衡。 技术 间接量热法、启动连续稳定同位素输注、肌肉 腿部动静脉差异的活检和测量 [(a-v)] 和 将使用血流量以及葡萄糖调节激素的反应 以实现上述具体目标。