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Originally Published in Climbing, No 165 December 15, 1996 – February 1, 1997
High on the gray limestone cliff, the slender young woman pulls the overhang, muscles taut and rippling. The picture of health? Maybe. Or maybe not. Under those powerful muscles, her bones may be developing the porous structure of a 70-year-old woman. She may be suffering from the Female Athletic Triad.
The name refers to the association of:
- Disordered eating
- Amenorrhea (absence of menstrual periods)
- Osteoporoses (bone fragility)
We all know that some athletes, faced with pressures to perform and fit the body image for their sports, will engage in disordered eating patterns. The patterns often do not meet the medical definition for anorexia or bulimia. More commonly, they involve various combinations of food restriction, obsessive thoughts about food, eating or body shape, and/or sporadic binge eating and purging (use of vomiting, laxatives, or diuretics). Eating disorders are common among female athletes, found in 15 to 62 percent. Approximately 10 times as many women develop eating disorders as men. Eating disorders can impair strength, endurance, and the ability to concentrate. In extreme cases, they can cause permanent damage to body organs or even death: the mortality rate for anorexia nervosa is between 4-18 percent.
Abnormal eating patterns, creating low weight and body fat, are also associated with amenorrhea in otherwise healthy athletes. It is not clear what actually triggers the loss of periods, but factors are body fat, exercise intensity, and perhaps emotional stress. Again, there’s a spectrum of severity. Some women do not menstruate, some do so regularly; others have regular periods but fail to ovulate, or develop an abnormally short luteal phase (the second half of the menstrual cycle). Any condition can cause temporary infertility.
Amenorrhea used to be considered a benign adaptation to athletic training. New studies, however, lead physicians to think the lack of periods should be seen as a warning that something is wrong. It reflects an alteration of normal hormonal cycles that can cause other problems aside from infertility.
Amenorrheic athletes also have an unusually high incidence of premature osteoporosis. Normally, human bone is constantly remodeled by resorption and new bone formation. When bone loss exceeds bone formation, the bone becomes more porous. Abnormal porosity is called osteoporosis. Bones are more fragile and the risk of stress fractures, spinal-compression fractures (causing the “dowagers hump”), hip fractures, and forearm fractures increases. The result can be pain, deformity and temporary or even permanent disability. Women are about eight times more likely to develop osteoporosis than men.
Generally, peak bone mass is achieved by age 18, although some additional bone, maybe gained until age 30. After that time, bone density gradually declines in both men and women, but it is accelerated and women after menopause. While moderate weight-bearing exercise can increase bone mass, some elite athletes have extremely low bone density. Low bone mass is most severe in women who began training the youngest, trained most intensely, started menstruating at later ages, and weighted the least. Although the strongest evidence for serious abnormalities in bone density have been found in and amenorrheic athletes, evidence indicates that bone mass is probably also affected in women with irregular periods, and possibly even women who menstruate but do not ovulate, or who have a luteal phase abnormality.
The triad is probably more dangerous for young athletes. Athletes seem more likely to develop the triad during adolescence and early adulthood. Intense training and low body weight seem to cause delayed menarche (first period starting at age 16 or older), which is associated with more menstrual irregularity and more bone mass problems. Also, since most bone mass is formed by young adulthood, low body fat and altered hormonal levels may cause a greater reduction in peak bone mass, leading to lower bone density in later years.
How long can you safely maintain an extremely low body weight? Bone loss may occur as early as six months after loss of periods. Probably the longer amenorrhea persists, the more severe the bone loss. If you gain enough weight to get your periods back, your bone density will improve. But after a year or more of amenorrhea, it probably will not return to normal.
Athletic amenorrhea and infertility are usually reversible if you gain weight and cut back on training. Many formerly amenorrhic women have later gotten pregnant. But some anorexic women do not have normal periods, even after significant weight gain.
What we don’t know yet is how low you can get your body fat safely. This probably varies from woman to woman. Normal menstrual cycles are probably a good indicator of bone health, although fertility may still be impaired by failure to ovulate or an inadequate luteal phase. Sudden increases in training intensity or rapid decreases in weight may be more likely to trigger amenorrhea than more gradual changes.
What should you do if you think you have this triad? Consider gaining a little weight (it might not take very much) until menstrual function normalizes. Eat a balanced healthy diet. Be sure you get enough calcium (1200 milligrams a day is recommended). Calcium alone won’t prevent osteoporosis, but without it, nothing else can work. If you don’t want to change your weight or training, talk to your doctor. Many sports physicians will recommend estrogen—usually some type of birth control pill. Because estrogen preserves bone mass in postmenopausal women, theoretically it should also help younger athletic women preserve bone mass. But don’t assume that if you’re on the pill you’re safe from bone loss. And don’t assume that if you’re really skinny you don’t need to worry about birth control—you might be in for a big surprise.