Effects of training on reproductive tissue blood flow in exercising pregnant rats

The purpose of this study were to investigate 1) whether treadmill training would attenuate the reduction in reproductive (RBF) and visceral tissue blood flow (VBF) that occurs during an acute bout of submaximal exercise (EX) in pregnant rats and 2) whether fetal number of fetal weight would be affected by training. One group (T) of female rats trained on a treadmill (10 degrees incline, 30 m/min) for 1 h/day 5 days/wk for 10 wk before becoming pregnant. A second group (UT) was run at the same speed and incline for 10 min/day 5 days/wk for 2 wk. T and UT rats were bred until pregnant. Skeletal muscle blood flow, RBF, and VBF were measured at pre-EX and at 1 and 10 min of EX (10 degrees incline, 30 m/min). No differences were observed before or during exercise between the two groups in RBF and VBF, heart rate, or mean arterial pressure. Both groups experienced decreases in VBF (except liver) and RBF from pre-EX to EX. In most muscles skeletal muscle blood flow increased for both groups from pre-EX to EX. Neither group experienced a change in mean arterial pressure from pre-EX to EX, but heart rate increased significantly for both groups. No differences were observed between groups in fetal number, fetal weight, or fetal resorptions. It was concluded that training does not significantly attenuate the reduction in RBF and VBF in pregnant rats that occurs during an acute bout of submaximal EX and that training does not affect fetal weight or fetal number.