AEROBIC EXERCISE AND AGE--METABOLIC, HORMONAL, AND CARDIOVASCULAR RESPONSES

体力劳动能力在成年期逐渐下降。 导致这种下降的原因是， 心血管和肺系统以及肌肉质量的减少。 我们的假设是， 老年人也与血液激素调节的变化有关 运动中的“燃料”调节。 本研究的目的是 检查年龄对血糖、游离脂肪酸 (FFA)以及调节能量储存的激素 （儿茶酚胺，胰高血糖素，胰岛素）在休息和长期 锻炼的 甘油、甘油三酯和乳酸的血浆水平 也测量。 运动是通过逐步增加水平 在跑步机上行走。 受试者在3次运动中每次步行10分钟 水平，40，50和60%，他们以前确定的最大氧气 消耗（VO2max），并在VO2max的70%下持续30分钟。 因此， 一次锻炼的时间是1小时。 代谢物和激素的血液样本 在每次练习结束时， 阶段，并在其终止后15分钟。 呼气样本 在运动前获得，在每个次最大运动的最后2分钟内 工作负载和恢复期结束时， 通气、耗氧量、二氧化碳产生和呼吸 商 在整个实验期间连续监测ECG。 期 健康受试者选自巴尔的摩的参与者 根据以下标准进行的老化纵向研究：否 心血管或其他重大疾病的证据，阴性跑步机 最大运动量测试，没有心脏活性药物，没有吸烟， 非肥胖且血压正常。 24个男人覆盖了成年人的年龄跨度 已经完成了方案。 结果将在明年进行分析。 血清睾酮水平的初步结果（基础和结束时 运动）在前19名男子表明，无论是原始水平和反应 与身体素质水平高度正相关 （VO2max）的参与者。

Physical working capacity decreases progressively during adult life. Contributing to this decline are decreases in function of the cardiovascular and pulmonary systems as well as a decrease in muscle mass. It is our hypothesis that decreased ability to perform physical work in the elderly is also associated with changes in the hormonal regulation of blood "fuel" regulation during exercise. The purpose of the present study is to examine the effect of age on plasma levels of glucose, free fatty acids (FFA) and of hormones responsible for regulating energy stores (catecholamines, glucagon, insulin) both at rest and during prolonged exercise. Plasma levels of glycerol, triglycerides and lactic acid are also measured. Exercise is accomplished by progressively increasing levels of treadmill walking. Subjects walk for 10 minutes at each of 3 exercise levels, 40, 50 and 60% of their previously determined maximal oxygen consumption (VO2max), and for 30 minutes at 70% of VO2max. Thus, duration of an exercise session is 1 hour. Blood samples for metabolite and hormone determinations are taken before exercise, at the end of each exercise stage, and 15 minutes after its termination. Samples of expired air are obtained before exercise, during the final 2 minutes of each submaximal workload and at the end of the recovery period for measurements of minute ventilation, oxygen consumption, carbon dioxide production, and respiratory quotient. The ECG is monitored continuously during the entire experimental period. Healthy subjects are selected from participants in the Baltimore Longitudinal Study of Aging according to the following criteria: no evidence of cardiovascular or other significant disease, negative treadmill maximal exercise test, no cardioactive medication, no cigarette smoking, non-obese and normotensive. Twenty-four men covering the adult age span have completed the protocol. Results will be analyzed in the coming year. Preliminary results on serum testosterone levels (basal and at the end of exercise) in the first 19 men show that both original levels and responses are highly positively correlated with the level of physical fitness (VO2max) of the participants.