Langenfeld M E, Hart L S, Kao P C
Med Sci Sports Exerc. 1987 Apr;19(2):83-6.
Ten adult male volunteers were studied to examine the effect on plasma beta-endorphin (B-EN) of bicycling and running for 1 h at 60% VO2max. All subjects were physically active and accustomed to both exercise modes (mean VO2max in ml X kg-1 X min-1; bicycling, 54; running, 59). Following preliminary VO2max tests, subjects participated in randomly ordered experimental sessions of bicycling and running for 1 h at loads requiring 60% of their mode-specific VO2max. Five subjects also participated in control sessions. Blood samples were collected immediately pre- and immediately post-exercise, and hematocrits were determined. Samples were centrifuged, separated, and plasma was stored at -50 degrees C until analysis for B-EN. Analysis involved separation of B-EN from beta-lipotropin by short column chromatography followed by radioimmunoassay. Despite an observed trend for elevated B-EN following exercise, there were no significant pre- to post-exercise differences (P greater than 0.05) in mean B-EN levels in any of the three sessions. Expressed as percentage change in B-EN, there were no significant differences between bicycling, running, or control. These results indicate that 1 h bicycling or running exercise at 60% VO2max does not consistently increase B-EN, and that responses are variable between individuals.
对10名成年男性志愿者进行了研究，以考察在60%最大摄氧量（VO2max）下骑行和跑步1小时对血浆β-内啡肽（B-EN）的影响。所有受试者均有体育锻炼习惯且熟悉这两种运动方式（以毫升×千克-1×分钟-1为单位的平均VO2max；骑行，54；跑步，59）。在进行初步的VO2max测试后，受试者按照随机顺序参加了骑行和跑步的实验环节，在各自运动方式特定的60%VO2max负荷下持续1小时。5名受试者还参加了对照环节。在运动前和运动后即刻采集血样，并测定血细胞比容。将样本离心、分离，血浆储存于-50℃直至进行B-EN分析。分析过程包括通过短柱色谱法将B-EN与β-促脂素分离，随后进行放射免疫测定。尽管观察到运动后B-EN有升高趋势，但在三个环节中的任何一个环节，运动前和运动后的平均B-EN水平均无显著差异（P>0.05）。以B-EN的百分比变化表示，骑行、跑步或对照之间均无显著差异。这些结果表明，在60%VO2max下进行1小时的骑行或跑步运动并不会持续增加B-EN，且个体之间的反应存在差异。
