BONE HEALTH IS NOT AFFECTED BY LUTEAL-PHASE ABNORMALITIES AND DECREASED OVARIAN PROGESTERONE PRODUCTION IN FEMALE RUNNERS

The primary purpose of this study was to determine whether decreased o varian progesterone production, associated with short and inadequate l uteal phases in exercising women, was associated with decreased bone m ineral density (BMD) and altered bone metabolism. Thirty-three eumenor rheic menstruating women participated in this study for 3 months. Subj ects were required to collect daily urine samples for three consecutiv e menstrual cycles and have blood and urine collected weekly. Daily ur ine samples were analyzed for free LH, estrone conjugates (E1C), and p regnanediol 3-glucuronide (PdG), adjusted for creatinine, whereas week ly blood and urine samples were analyzed for bone markers, estradiol, progesterone, FSH, and LH. Based on the analyses of these samples, sub jects were divided into three groups: sedentary ovulatory (SedOvul; n = 9), exercising ovulatory (ExOvul; n = 14), and exercising luteal pha se defects (ExLPD; n = 10). The three groups were matched for age (27. 6 +/- 1.0 yr), weight (60.6 +/- 1.9 cm), and reproductive maturity (14 .5 +/- 1.0 yr). PdG production during the luteal phase was lower (P = 0.004) in the ExLPD women compared to that in the SedOvul group (2.4 /- 0.4 us. 5.1 +/- 0.6 ng/mL creatinine, respectively). The ExOvul gro up also had less (P < 0.01) PdG production during the luteal phase (3. 5 +/- 0.3 ng/mL creatinine) compared to the SedOvul group. The total p roduction of PdG, as assessed by area under the curve analysis, was al so lower (P < 0.001) in the ExOvul and ExLPD groups compared to that i n the SedOvul group. E1C production, however, was not different (P > 0 .05) among the groups, except for E1C during the early follicular phas e, which was lower (P = 0.043) in the ExLPD group than that in the Sed Ovul group. BMD and biochemical markers of bone metabolism were unaffe cted by and not associated with the compromised progesterone environme nt, but BMD values at the proximal femur (r = 0.354; P = 0.061) and to tal body (r = 0.359; P = 0.056) were associated with decreased early f ollicular E1C production. We conclude the following. 1) Luteal phase d isturbances occur independent of training volume, and volume of traini ng does not have to be severe to result in menstrual disturbances. 2) As a result of exercise, disturbance in progesterone production is not associated with decreased bone mass. 3) Long follicular phases are as sociated with reduced estrogen production during the early follicular phase, which are both associated with decreased bone mass. 4) Provided the estradiol status is adequately maintained, BMD is unaffected by d ecreased progesterone production associated with short and inadequate luteal phases in exercising women.