Abstract:

BACKGROUND: Researches have showed that long term aerobic exercises can lead to component changes of female estrogen and bone mineral density, and the mechanism is still unclear.
OBJECTIVE: To observe the influence of long-term low and medium intensity swimming movements on estrogen level and bone mineral density of female SD rats.
METHODS: Forty SD rats were randomly divided into swimming group Ⅰ, group Ⅱ and control group. The two swimming groups began to swim in a graded exercise testing mode from the first week. The swimming movements lasted for 4 weeks and 7 weeks respectively for group Ⅰand group Ⅱ. No exercises were performed in the control group. After 1-hour swimming every time, the number and form of desquamated vagina cells in both groups were dynamically observed under electron microscope. 
RESULTS AND CONCLUSION: Compared with the control group, the number of cells at the bottom of the rats’ vagina of group Ⅱ increased week by week, and reached the peak at the seventh week (P < 0.01). Serum estradiol, progesterone and testosterone levels of groupⅡ obviously increased (P < 0.01). Bone mineral densities of the lumbar vertebra and femur in group Ⅰwere higher than those in the control group (P < 0.05), but lower than those in group Ⅱ (P < 0.05, P < 0.01). The results indicated that long-term low and medium intensity swimming movements can promote the bone mineral density and estrogen level of female rats.