Silverman H G, Mazzeo R S
Department of Kinesiology, University of Colorado, USA.
J Gerontol A Biol Sci Med Sci. 1996 Jan;51(1):B30-7. doi: 10.1093/gerona/51a.1.b30.
Neuroendocrine adjustments to maximal and submaximal exercise were investigated in men as a function of age and training status. Twenty-four trained cyclists and 23 sedentary men constituting a young (M = 22.9 yrs, n = 16), middle-aged (M = 44.9 yrs, n = 16), and old (M = 65.5 yrs, n = 15) group performed both a maximal (GXT) and a 45-minute submaximal exercise test (cycle ergometer) at the workload corresponding to their lactate threshold. Plasma lactate, glucose, growth hormone, cortisol, norepinephrine, and epinephrine concentrations were analyzed both at rest and during exercise. Peak oxygen consumption (VO2 peak) was lower with age; however, all trained groups had higher values for VO2 peak compared to sedentary groups, regardless of age. Lactate threshold, when expressed in absolute terms, was lower with advancing age (sedentary decreases 9 and 26%: trained decreases 19 and 35% for middle-age and old, respectively, when compared to young). Pre-exercise plasma norepinephrine levels were higher with age in both trained and sedentary subjects. Cortisol levels were lower with age for sedentary subjects and were significantly elevated in trained subjects across all age groups. Endurance training resulted in increased hormonal responses, as measured by plasma concentrations, to both maximal and submaximal exercise across all age groups. However, regardless of training status, age-related declines were observed in peak responses for lactate, growth hormone, and cortisol during the GXT. During the 45-minute submaximal exercise test, these age-related differences that had been present in the GXT were abolished. This submaximal test represented a lower absolute work load for old compared to young as well as sedentary compared to trained subjects; however, individuals were working at similar relative exercise intensities. We conclude that older individuals are capable of similar hormonal responses to submaximal exercise of identical durations and intensities as their young and middle-aged counterparts, and that chronic endurance training can enhance the hormonal response to exercise in all age groups.
研究了男性在最大和次最大运动时神经内分泌的调整情况，该调整是年龄和训练状态的函数。24名受过训练的自行车运动员和23名久坐不动的男性组成了年轻组（平均年龄22.9岁，n = 16）、中年组（平均年龄44.9岁，n = 16）和老年组（平均年龄65.5岁，n = 15），他们在对应其乳酸阈值的工作量下进行了最大运动试验（GXT）和45分钟的次最大运动试验（自行车测力计）。在休息和运动期间分析血浆乳酸、葡萄糖、生长激素、皮质醇、去甲肾上腺素和肾上腺素的浓度。最大摄氧量（VO2峰值）随年龄增长而降低；然而，所有受过训练的组与久坐不动的组相比，VO2峰值更高，与年龄无关。以绝对值表示时，乳酸阈值随年龄增长而降低（久坐不动者中年和老年组分别比年轻组降低9%和26%；受过训练者中年和老年组分别比年轻组降低19%和35%）。在受过训练和久坐不动的受试者中，运动前血浆去甲肾上腺素水平均随年龄增长而升高。久坐不动的受试者皮质醇水平随年龄增长而降低，而在所有年龄组的受过训练的受试者中皮质醇水平显著升高。耐力训练导致所有年龄组血浆浓度所测量的对最大和次最大运动的激素反应增加。然而，无论训练状态如何，在GXT期间，乳酸、生长激素和皮质醇的峰值反应均出现与年龄相关的下降。在45分钟的次最大运动试验中，GXT中出现的这些与年龄相关的差异消失了。与年轻人相比，该次最大试验对老年人而言代表较低的绝对工作量，与受过训练的受试者相比，久坐不动的受试者也是如此；然而，个体的相对运动强度相似。我们得出结论，老年人在相同持续时间和强度的次最大运动中能够产生与年轻和中年同龄人相似的激素反应，并且长期耐力训练可以增强所有年龄组对运动的激素反应。
