[State of nutrition and diet habits versus estradiol level and its changes in the pre-season preparatory period for the league contest match in female handball and basketball players].

BACKGROUND

Intense exercise is known to induce menstrual disturbances--irregular menstrual cycles, oligomenorrhea and amenorrhea in female athletes. Menstrual disturbances, followed by hypoestrogenism, are associated with infertility decreased bone mineral density high prevalence of stress fractures, and endothelial dysfunction.

OBJECTIVES

The aim of the study was to assess the effect of nutrition and diet habits on the estradiol level and its changes in the pre-season preparatory period for the league contest match in female handball and basketball players.

MATERIALS AND METHODS

Fifty healthy young female handball and basketball players were enrolled into the study before the opening of the season, after a 2-month holiday period, without regular physical activity and diet restrictions. Serum estradiol was determined at the beginning and after 3 months of moderate aerobic training. Each woman was studied between the 3rd and 5th day of her menstrual cycle. In all subjects, medical history was obtained, together with the anthropometric measurements (body mass and height). The body mass index was calculated according to the standard formula. The use of hormonal contraception in the last 3 months, low-caloric diet in the last 6 months, body mass changes of more than 3 kilograms in the last 6 months, secondary amenorrhea and stress fractures in medical history constituted the exclusion criteria. Informed consent was obtained from each participant and the study protocol was approved by the Ethics Committee of the Medical University of Silesia. Venous blood samples (2 ml) for estradiol levels measurements were taken twice: at the beginning of the preparatory period and after three months of moderate aerobic exercise training (20 hours per week). Blood samples were collected according to the kit manufacturer's recommendations. Serum and plasma samples were stored frozen at -80 degrees C. Serum estradiol was determined by enzyme-linked immunosorbent assay (ELISA) (DRG Instruments GmbH, Marburg, Germany) with a lower limit of sensitivity of 9.714 pg/mL; the intra- and inter-assay coefficients of variation were 4.7% and 7.8%. All statistical analyses were performed with the use of Statistica 8.0 software. The results are presented as means +/- SD. The Wilcoxon rank test was used to compare the before and after exercise measurements. The Mann-Whitney U test was used for subgroups comparisons. The results were considered statistically significant when the p value was less than 0.05.

RESULTS

After a 2-month holiday period, without regular physical exercise, p < 0.01) serum estradiol level was significantly lower in the basketball than handball players (48.7 +/- 19.6 vs. 62.3 +/- 18.9 pg/ml, p < 0.01). Although, no body mass changes were noticed (delta = - 0.3 +/- 0.3 kg), after 3 months of moderate aerobic training estradiol level was significantly decreased in the whole study population (58.0 +/- 20.0 vs. 41.4 +/- 18.9 pg/ml, p < 0.001).

CONCLUSIONS

Diet habits and nutrition did not correlate with estradiol plasma levels in female handball and basketball players after a 2-month holiday period. Regular exercises correlate with the decrease of serum estradiol level even without body mass changes.