Abstract

The influence of forced treadmill exercises on the length of oestrous cycles was investigated in female rats until age of 460 days. At the age of 20 days rats were randomly divided into three groups. One group served as control (n=20) and two other groups were subjected to forced treadmill running (25 m/min, incline +10 degree, 1 h per day, 4 days a week) with the onset of training before puberty at the age of 20 days (Group T-20, n=17), or after puberty, at the age of 70 days (group T-70, n=22). Once a month, starting at the age of 90 days, exercise tests were performed until exhaustion. Vaginal smears were taken throughout 21 day periods at different ages. On the day before and two days after the run to exhaustion the rats were observed in the open field. In females which started training before puberty (Group T-20) the mean number of oestrous cycles was significantly lower, and mean cycle length higher, than in the control group. Similar results were found in Group T-70 but not before the age of 120-140 days. After the age of 250 days, when the training had been discontinued, the values of both parameters were similar in the control and running groups. Verf.-Referat