Impact of different exercise intensities on pregnant rats and on their offspring

Abstract This study aimed at evaluating the levels of different maternal exercise intensities on maternal and fetal outcomes. Wistar rats were mated and the pregnant rats were distributed into four experimental groups (n = 13 animals/group): Control (Not exercise group - 0% of the anaerobic threshold- AT), mild (20%), moderate (80%), and heavy-exercise intensity (140% of AT). These AT were matched to the load of 0, 1, 4 and 7% of the body weight of the animal related to swimming-induced physical intensity. In pregnancy, biomarkers related to maternal blood gases, oxidative stress, metabolism, and reproductive performance, and outcomes of their offspring were analyzed. The mild and moderate-swimming caused no change on implantation, live fetus numbers and oxidative stress status. However, the rats submitted to mild-exercise presented respiratory alkalosis and the heavy-exercise group showed respiratory acidosis. In addition, fetuses of the heavy-exercise dams were smaller for gestational age and lower serum adiponectin levels compared to those of other groups. In conclusion, the moderate-exercise intensity caused beneficial effects for maternal environment and the mild and moderate-exercise presented similar fetal repercussions. Nevertheless, the heavy-exercise intensity caused maternal metabolic alterations that damaged the fetal growth. Therefore, these findings confirm that physical intensity should be carefully conducted to avoid maternal complications and, consequently, compromised fetal repercussions.

摘要 本研究旨在评估不同母体运动强度对母体及胎儿结局的影响。将Wistar大鼠交配后，按随机原则将孕鼠分为4个实验组（每组n=13只）：对照组（不运动组——无氧阈值（anaerobic threshold, AT）的0%）、轻度运动组（20% AT）、中度运动组（80% AT）及大强度运动组（140% AT）。上述AT对应游泳运动强度下，动物体重的0%、1%、4%与7%的负荷。妊娠期间，本研究分析了母体血气、氧化应激、代谢及生殖性能相关的生物标志物，同时检测了子代的各项结局指标。结果显示，轻度与中度游泳运动对大鼠着床率、活胎数及氧化应激状态均无显著影响。但轻度运动组孕鼠出现呼吸性碱中毒，大强度运动组孕鼠则出现呼吸性酸中毒。此外，相较于其他组，大强度运动孕母的胎鼠按胎龄而言体积更小，血清脂联素水平更低。综上，中度运动强度对母体内环境具有有益作用，轻度与中度运动对子代的影响效果相近。然而，大强度运动可引发母体代谢异常，进而损害胎鼠生长发育。因此，本研究结果证实，运动强度需谨慎把控，以避免母体并发症的发生，从而防止子代结局受损。