Women Running Marathons: Do Benefits Outweigh Risks?
When I mentioned recently that I was training for my fifth marathon, a woman I know looked at me with concern and said, "You know, women aren't supposed to run more than one marathon. It's bad for your reproductive health." When my friend Chandler started training for the Boston Marathon, which was three months before her wedding, her soon-to-be mother-in-law was dismayed. "That's such a silly thing to do," she said. "Don't you know how dangerous that is?"
This type of talk led me to wonder: how dangerous is it for women to run marathons? In fact, is it dangerous at all? Some people certainly seem to think so—and there are plenty of stories out there about elite women runners who have become too thin, missed periods, and had other health problems. But there are also thousands of healthy women who run marathons every year.
Are Women Marathoners Endangering Their Health?
"It is generally not dangerous for women to train for and run in marathons, as long as proper nutrition is maintained and precautions are taken," says Michael Lu, MD, assistant professor of obstetrics and gynecology at the UCLA School of Medicine.
Bill Comer, MPH, director of development for Community Running, a running club for "middle of the pack" runners, agrees. "I've helped over 1,000 people run marathons, and about 65% of them have been women," he says. "In my experience, marathon training adds to the quality of life. Most marathoners get healthier."
As with most major physical undertakings, however, there are some risks. Most of these are related to going to extremes: training too hard, eating too little, getting too thin. "The greatest potential gynecologic risks of marathon training for women involve ]]>amenorrhea]]> (no periods), ]]>osteoporosis]]>, and disordered eating, in what is commonly called the female athlete triad," Dr. Lu explains.
Avoiding the Triad
To protect your health as a female runner, you must be especially careful to monitor your behavior and make sure you don't unknowingly fall into the female athlete triad.
In their article on the female athlete triad in American Family Physician, Julie Hobart, MD, and Douglas Smucker, MD, MPH, state that the female athlete triad is a combination of three interrelated conditions that are associated with athletic training: disordered eating, amenorrhea (absence of menstruation), and osteoporosis. According to Hobart and Smucker, "Athletic endeavors such as . . . distance running...that emphasize low body weight and a lean physique can increase the risk of developing the female athlete triad."
Many athletes with eating disorders don't meet the strict criteria for ]]>anorexia nervosa]]> or ]]>bulimia nervosa]]>, but do exhibit some disordered eating behaviors. According to Charlotte Sanborn, PhD, and her colleagues in their article, "Disordered Eating and the Female Athlete Triad," in Clinics in Sports Medicine, these behaviors can include restricting food intake, using diet pills and laxatives, and having periods of binge eating and purging. Sanborn and colleagues say the concern with athletes is that "the pathway to a frank eating disorder often begins with simply monitoring food intake, progresses to restricting foods . . . then evolves into limiting acceptable foods, and finally becomes voluntary starvation."
The amenorrhea of the female athlete triad is caused by a combination of excessive exercise and insufficient nutrition. These factors can lead to decreased levels of estrogen, which can cause menstruation to cease. According to Sanborn and her colleagues, the highest frequency of amenorrhea is among runners and ballet dancers. They believe the calorie deficit many runners face may be "responsible for the reproductive disorder." Undernutrtion and/or over exercise somehow affect the hypothalamus leading to amenorrhea and infertility. Two chemicals responsible for this include leptin and ghrelin. Serious consequences of amonorrhea include loss of bone mass and increased risk of stress fractures, infertility, and potential cardiovascular consequences due to decreased estrogen.
With respect to the female athlete triad, Sanborn and colleagues explain that osteoporosis refers to premature bone loss or inadequate bone formation. Amenorrheic athletes are at greater risk of low bone mass and stress fractures. Plus, once you start losing bone density, you may not be able to get it back—which can lead to all sorts of problems with your hips, knees, and vertebral column later in life. The causes of osteoporosis in female athletes may include estrogen deficiency, nutritional deficiencies and the adverse effect of leptin on bone.
The American College of Sports Medicine says amenorrhea should be considered a warning symptom of triad-related osteoporosis and the complications that can result. If you are training for a marathon and start missing periods, get a medical evaluation within the first three months. Amenorrhea is not a normal consequence of training. Other possible symptoms of the triad include fatigue, ]]>anemia]]>, electrolyte abnormalities, and depression caused by dieting.
Eat Enough and Eat Well
A great benefit to training for a marathon is that you can eat more—in fact, you have to so you can replace all the calories you burn during training. Be careful to avoid the first point of the female athlete triad, and make sure your diet is adequate to meet your body's increased demands.
"In general, the diet should provide adequate calories to meet the athlete's energy needs. It should be balanced, providing all macronutrients and micronutrients from a wide variety of foods," says Dr. Lu. "It should also be consistent between races to avoid frequent and drastic changes in body composition."
To make sure you get enough ]]>calcium]]> while training, Comer recommends adding a supplement with calcium to your daily routine. He also points out that protein and ]]>iron]]> are extremely important. If you're not a vegetarian, lean red meat is a great source of both protein and iron. Vegetarians should look for alternative means of getting adequate iron and protein.
If you're still concerned about low estrogen levels and losing bone density, talk to your doctor about taking oral contraceptives or other hormones. "Small studies have shown that the use of birth control pills may increase bone density and decrease the risk of stress fracture in patients with athletic amenorrhea," Dr. Lu says.
Keep Training in Check
One of the contributing factors to the female athlete triad is excessive exercise—and with marathon training, that's obviously a possibility. "The amount you can train is largely determined by genetics. The less there is of you, the easier it is to do weight-bearing exercise," Comer says. "But if you start to get too competitive and try to shed weight so your times will get faster, there can be health risks."
As with most things, Comer says, moderation in marathon training is key. Don't do more than your body can handle—and that amount is different for every runner.
Comer recommends getting professional help to figure out how much training is appropriate for you. "It's always best to run with a group and under the tutelage of an experienced running coach," he says. "But if that isn't an option for you, there are plenty of online resources to help you with training."
American College of Sports Medicine
Healthy Living Unit (Public Health Canada)
Dietitians of Canada
Fenichel RM, Warren MP: Anorexia, bulimia, and the athletic triad: evaluation and management. Curr Osteoporos Rep. 2007;5:160-4.
Gabel KA. Special nutritional concerns for the female athlete. [review] Curr Sports Med Rep. 2006;5(4):187-191.
Hobart J, Smucker D. The female athlete triad. American Family Physician. 2000.
Nattiv A, Loucks AB, Manore MM et al: American College of Sports Medicine position stand. The female athlete triad. Med Sci Sports Exerc. 2007;39:1867-82.
Nichols JF, Rauh MJ, Lawson MJ, Ji M, Barkai HS. Prevalence of the female athlete triad syndrome among high school athletes. Arch Pediatr Adolesc Med. 2006;160(2):137-142.
Sanborn C, et al. Disordered eating and the female athlete triad. Clinics in Sports Medicine. 2000.
Troy K, Hoch AZ, Stavrakos JE. Awareness and comfort in treating the female athlete triad: are we failing our athletes? WMJ. 2006;105(7):21-24.
Last reviewed January 2009 by ]]>David Juan, MD ]]>
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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