Bessinger Raymond C, McMurray Robert G, Hackney Anthony C
Department of Nutrition, University of North Carolina, Chapel Hill, USA.
Am J Obstet Gynecol. 2002 Apr;186(4):757-64. doi: 10.1067/mob.2002.122093.
This study was undertaken to examine substrate utilization and hormonal responses to moderate intensity exercise in the same group of women across gestation.
Glucose, triglyceride, insulin, glucagon, cortisol, growth hormone, and blood urea nitrogen levels were measured in 12 women at rest and after exercise. Heart rate, oxygen uptake, and respiratory exchange ratio were measured at rest and during exercise. Urine urea nitrogen levels, urine volume, and creatinine levels were measured 24 hours before and after exercise. Each woman completed a 30-minute treadmill walk at 65% of her predicted maximal heart rate at the same time of day during the 22nd and 33rd weeks of gestation and at 14 weeks after delivery.
There were no significant differences between exercise trials in oxygen uptake, respiratory exchange ratio, or heart rate. Pregnancy elevated resting triglyceride levels but lowered plasma glucose levels. Exercise during pregnancy caused a reduction in plasma glucose levels but elevated circulating triglyceride levels (P <.05). Resting levels of cortisol, growth hormone, and insulin were elevated during pregnancy compared with after delivery, but resting glucagon levels were not affected by pregnancy. Exercise caused circulating levels of cortisol, growth hormone, and glucagon to increase (P <.05). The exercise-induced change in the cortisol level was greater during pregnancy than that after delivery. The exercise-induced changes in growth hormone and glucagon levels were greatest after delivery compared with those during pregnancy (P <.05). Exercise reduced insulin levels (P <.05), with the greatest reduction at 33 weeks' gestation. There were no significant differences in urine urea nitrogen excretion as a result of exercise.
Certain substrate and hormonal responses to exercise are altered as pregnancy progresses. Quantitatively, protein appears to be a relatively unimportant fuel during a 30-minute bout of moderate intensity exercise in this group of women evaluated during pregnancy and after delivery. Furthermore, a 30-minute bout of moderate intensity exercise would not be expected to compromise fetal amino acid availability.
本研究旨在考察同一组女性在整个孕期进行中等强度运动时的底物利用情况及激素反应。
对12名女性在静息状态及运动后测量血糖、甘油三酯、胰岛素、胰高血糖素、皮质醇、生长激素和血尿素氮水平。在静息状态及运动过程中测量心率、摄氧量和呼吸交换率。在运动前后24小时测量尿尿素氮水平、尿量和肌酐水平。每位女性在妊娠第22周和第33周以及产后14周的同一天，以其预测最大心率的65%在跑步机上完成30分钟的步行。
各运动试验在摄氧量、呼吸交换率或心率方面无显著差异。妊娠使静息甘油三酯水平升高，但降低了血浆葡萄糖水平。孕期运动导致血浆葡萄糖水平降低，但循环甘油三酯水平升高（P<.05）。与产后相比，孕期静息状态下皮质醇、生长激素和胰岛素水平升高，但静息胰高血糖素水平不受妊娠影响。运动导致循环中的皮质醇、生长激素和胰高血糖素水平升高（P<.05）。孕期运动引起的皮质醇水平变化大于产后。与孕期相比，运动引起的生长激素和胰高血糖素水平变化在产后最大（P<.05）。运动使胰岛素水平降低（P<.05），在妊娠33周时降低幅度最大。运动对尿尿素氮排泄无显著影响。
随着孕期进展，运动时某些底物和激素反应会发生改变。从数量上看，在这组孕期及产后评估的女性中，蛋白质在30分钟中等强度运动期间似乎是相对不重要的燃料。此外，预计30分钟中等强度运动不会损害胎儿的氨基酸供应。
