Effect of exercise training during pregnancy: maternal and fetal responses of the rat

Pregnancy duration, offspring number, body weight gain per day, as well as offspring body and heart weights were studied in pregnant Wistar rats subjected to exercise training at relative work loads of 60, 70, 80 or 90% of maximum oxygen consumption (VO2max) (N = 6 for each group). Pregnancy duration, offspring number and heart weight of the rats subjected to exercise during pregnancy were not different from the control group not subjected to exercise training. Body weight gain per day of pregnant rats subjected to exercise was 4.64 +/- 0.21, 4.79 +/- 0.22 and 4.72 +/- 0.12 g, respectively, for work loads of 70, 80 or 90% of VO2max. This decrease of body weight gain per day was significantly different (P less than 0.05) from the control group (5.69 +/- 0.22 g). The offspring body weight decreased in the rats submitted to work loads of 70, 80 and 90% of VO2max (5.30 +/- 0.05, 5.34 +/- 0.02 and 5.24 +/- 0.01 g, respectively) by comparison to the control group value (5.73 +/- 0.07 g). These results suggest that only intense exercise could impair body weight gain in pregnant rats and their offspring.