Most women today are very aware of the benefits of exercise and maintaining a normal body weight. Benefits include improved cardiovascular health, stronger bones, and better moods. However, some women have a hypercritical assessment of their body weight that can lead to a negative cycle of excessive exercise and strict dieting. This combination can result in bodily harm rather than health benefit.
One of the signs that an exercise and diet regimen is doing more harm than good is amenorrhea (ceasing to have menstrual periods) or oligomenorrhea (having few, irregularly occurring periods).
Menstrual disorders are not caused by excessive exercise alone. Inadequate calorie intake relative to the amount of energy expended is the baseline cause of menstrual disruption. Researchers have found that a minimal amount of body fat is required for normal reproductive function. The energy in the body fat is used by the hypothalamus to make and release hormones that act on the ovaries, where estrogen in produced. Without that hormonal cycle, not enough estrogen is available for the menstrual cycle resulting in infertility.
Aside from infertility, not enough estrogen can result in weak bones in spite of the bone-building effect of weight-bearing exercise. Athletes who have poor eating habits and are underweight experience stress fractures more often than those with normal eating habits. Stress fractures are said to occur in up to 30 percent of ballet dancers.
A combination of strict dieting, menstrual disorders, and low bone density is called ‘the female athlete triad.’ Women in sports that involve subjective scoring (like figure skaters or gymnasts) and those with low body weight (like runners and ballet dancers) have a higher incidence of amenorrhea than other athletes like swimmers.
Not all women with exercise-induced amenorrhea have an eating disorder. The amount of exercise or the degree of weight loss that can cause menstrual and fertility problems varies from woman to woman. Some women are genetically predisposed to exercise-induced menstrual disorders. Amenorrhea or oligomenorrhea are more likely to occur if an increase in exercise occurs suddenly, such as last minute preparation for running a marathon. Gradually increasing exercise is less likely to cause problems.
Treatment is not complicated. Calorie intake should be increased and the frequency or intensity of the exercise routine should be decreased. While hormonal treatment will induce a menstrual cycle and decrease the risk of bone loss, it does not affect the underlying cause of infertility. A hormone-induced pregnancy is at risk if a woman’s diet is deficient in adequate nutrients for her pregnant self and her baby. Miscarriage, poor fetal growth and development, and babies with low birth weight are more likely to occur in underweight women.
For women with a history of eating disorders or distorted body image who are resistant to decreasing the intensity of their exercise or gaining weight, behavioral therapy is strongly recommended.
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- Robinson TL, Snow-Harter C, Taaffe DR, et al. Gymnasts exhibit higher bone mass than runners despite similar prevalence of amenorrhea and oligomenorrhea. J Bone Miner Res. 1995;10:26.
- Warren MP. Amenorrhea and infertility associated with exercise. UpToDate. Updated November 04, 2014. Accessed March 24, 2015.
- Young N, Formica C, Szmukler G, Seeman E. Bone density at weight-bearing and nonweight-bearing sites in ballet dancers: the effects of exercise, hypogonadism, and body weight. J Clin Endocrinol Metab. 1994;78:449.