Effect of physical training on metabolic responses of pregnant rats submitted to swimming under thermal stress

BACKGROUND The aim of this study is to assess the effect of pre-pregnancy physical training on metabolic responses and its effects on offspring. METHODS Three groups of rats (n = 7 in each group): sedentary pregnant rats (PS), exercised during pregnancy (PE) and pregnant rats trained before and during pregnancy (PT) were compared. They were separated into three subgroups regarding water temperature: 28°C, 35°C or 39°C. Plasma triglycerides and glucose levels, weight gain during pregnancy and rectal temperature pre and post exercise (swim), as well as the offspring size and weight were analysed. RESULTS Rectal temperature post exercise was lower than pre exercise at 28°C and 35°C, and higher at 39°C. Weight gain was lower at 39°C for the PT group and at 35°C for the PT and PE groups compared to the PS group. Plasma glucose, at 28°C and 39°C for PS and PE groups, was higher than those obtained at 35°C, while triglycerides were lower. For trained rats, plasma glucose and triglycerides were similar at all water temperatures. Trained rats presented lower triglyceride values at 35°C, and higher triglyceride values at 39°C compared to PS group. Glucose presented inverse results. None of the groups presented fetal reabsorption. However, in the PS group, the offspring presented lower weight gain at 28°C than at 35°C and 39°C. CONCLUSIONS These results suggest that pre-pregnancy physical training induces steady values of triglycerides and glucose during exercise at all water temperatures.