Menstrual status and long-term cardiovascular effects of intense exercise in top elite athlete women

University dissertation from Stockholm : Karolinska Institutet, Department of Women's and Children's Health

Abstract: Although physical exercise is generally beneficial for health, female athletes run an elevated risk of developing chronic energy deficiency, with ensuing severe consequences such as reproductive dysfunction, bone demineralization, more frequent injuries, impaired performance, and adverse cardiovascular effects. However, at present little is known about these issues with respect to sportswomen competing at the Olympic level, or about the long-term cardiovascular consequences of intense training for women. Our aims were to characterize patterns of weight control in female and male Olympic athletes, as well as to assess the menstrual status, body composition, biomarkers of energy availability and circulating levels of sex hormones in Olympic sportswomen. In addition, cardiovascular function and the associated serum lipid levels and body composition of postmenopausal former elite athletes were compared to these same parameters in control subjects. Among the 223 Swedish athletes who competed in the 2002 and 2004 Olympic Games, those participating in sports that emphasize leanness demonstrated less desirable strategies for weight and more frequent illness than competitors in other disciplines, particularly in the case of the male athletes. Among 90 of these sportswomen, and especially among the endurance athletes, menstrual dysfunction (MD) was frequent. The most common cause of MD was polycystic ovary syndrome (PCOS), rather than hypothalamic inhibition. Furthermore, no signs of chronic energy deficiency, as evaluated on the basis of body fat content and biomarkers of energy availability, were observed. Bone mineral density (BMD) was generally high and none of these athletes exhibited osteopenia or osteoporosis. Furthermore, among 20 postmenopausal former elite athletes we observed enhanced endothelial function in those not utilizing hormone replacement therapy, whereas the use of such therapy was associated with endothelial function similar to that of sedentary control subjects. Serum levels of cholesterol and low-density lipoprotein, body fat content and the frequency of ST-depressions in exercising electrocardiograms were lower in the former athletes; whereas the exercise capacity, dimensions of the left and right cardiac ventricles, and left atrial and stroke volumes were all significantly greater than in control subjects. We conclude that the weight control practices employed by Olympic athletes participating in disciplines that emphasize leanness appear to be suboptimal, although female athletes may have adopted healthier nutritional practices than the men. Furthermore, our findings challenge the contemporary concept that reproductive dysfunction in sportswomen is typically a consequence of chronic energy deficiency. Here, the single most frequent underlying cause of menstrual disturbances in Olympic athletes was the hyperandrogenic disorder PCOS. Long-term strenuous exercise is associated with minor changes in cardiac structure, but overall beneficial effects on exercise capacity, vascular function and cardiovascular risk factors.

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