Take Care of Your Bones

by Sally Wendkos Olds

"Exercise is a boon to bone," says exercise physiologist Rae Jean Stillman, Ph.D., of the University of Illinois. Sure. Just what we've always heard. The mantra for building strong, healthy bones has always been weight-bearing exercise, healthy diet, no smoking, drinking only in moderation. Sounds like the regimen followed by all the runners I know. Why, then, are some runners including some very young women finding out, to their horror, that their bone mass is lower sometimes much lower than that expected for women of their age?

Take world-class marathoner Gordon Bakoulis, who in 1994 at age 32 discovered that her bone density was below the normal range for her age group. Or ultra runner Jennifer Aviles, 50, who since 1977 has been running long distances and eating a healthy diet, who has never had a stress fracture and who recently learned that her bone density is only 83 percent of that expected for her age.

What do findings like these mean for these women's lives and running careers? What do they mean for the rest of us, including back-of-the-packers like me? To answer these questions, I talked to doctors and researchers about the significance of bone density, the risk for osteoporosis, the relationship between strong bones and running and what the woman runner should do.

Bone density and osteoporosis

As living tissue, our bones change continually throughout our lives. As old bone tissue breaks down, new tissue replaces it in a process called remodeling. Optimally and usually, breakdown and buildup occur in a good balance that keeps the skeleton strong. With weight-bearing exercise and calcium, we build bone mass, and the hormones our bodies produce (estrogen for women, testosterone for men) slow the course of bone breakdown.

Typically, bone continues to build until the mid-30s. Then between ages 35 and 50 the process reverses, and everyone slowly loses some bone mass. The bones develop holes and become lighter. From ages 50 to 60, this loss in bone density speeds up in women, to slow down again after 60. Women lose more bone than men do, partly because their skeletons are lighter and partly because estrogen production drops off suddenly with menopause, unlike testosterone production, which decreases only gradually with age.

A frightening divergence from this pattern sometimes occurs when bone begins to thin and get brittle much earlier in life. The "female athlete triad"as research physiologist Barbara Drink water, Ph.D., calls the combination of disordered eating, amenorrhea (lack of menses), and osteoporosis is most likely to affect adolescent girls and young women who exercise so much or eat so little (or both) that a domino effect occurs in their bodies.

As the body fat level falls dangerously low, the ovaries don't make enough estrogen. Without enough estrogen, the production of new bone cannot keep up with the resorption of dying bone. It is as if a false menopause is occurring.

When dying bone tissue is not replaced quickly enough, the bones become weak and porous, leading to osteoporosis, a disease of fragile bones, which leads to an increased risk of fracture. Pictures clearly show the difference between healthy and osteoporotic bone.

Generally, diagnosis of osteoporosis relies on a standard of bone density based on what is normal for a healthy 30-year-old. Under this definition, almost half of all postmenopausal women aging normally are diagnosed as having this disease. A more realistic definition sets an age-appropriate standard for bone mass and determines what level of diminished bone mass makes someone particularly susceptible to fractures.

The gravity of the problem for young athletes shows up as sports physicians see some women in their twenties who should still be building bone but who, instead, have bone density like that of women in their seventies and eighties. This bone loss is irreversible.

Bone loss often progresses gradually, with no symptoms until a woman breaks a bone and is diagnosed as osteoporotic. Although many women do not suffer from the condition, for those who do the consequences are grave. One common fracture site is the spinal vertebrae. When these small bones break, a permanent curve (the "dowager's hump") can develop in the upper back; other possible consequences are pain, loss of height, and malfunctioning of the internal organs. A minor fall may result in a broken wrist or ankle, which may take many months to heal. Hip fractures are even more serious. An 85-year-old woman runs a 1 in 6 chance of breaking a hip; among those who do, 50 percent spend time in a nursing home, 25 percent never walk again, and 20 percent die within a year.

As young women especially competitive athletes work hard to maintain unnaturally thin bodies, I look at them and wonder whether this is why premature osteoporosis is more common worldwide than it used to be. A recent analysis of old human bones, from 87 British women buried from 1729 to 1852, found that their bones were stronger than contemporary ones.

In a culture wild about strenuous exercise and thin bodies, one member of the "Dead Runners Society" recently worried on the Internet that "too many baby boomers coming down the pike are running themselves into osteoporosis." Will today's champion athletes become tomorrow's disabled old women?

Who is at risk

Both calcium and estrogen are needed to build bone. A female who trains so intensely and eats so little that menstruation doesn't begin at a normal age or stops for months or even years is getting a clear signal that her estrogen level has plummeted alarmingly. This kind of menstrual dysfunction affects ballerinas, skaters, and gymnasts as well as runners. Sometimes these young women suffer stress fractures, but usually their only warning of a problem is lack of menstruation.

This is not to say that women should not compete or that they are weak. It's not the exercise itself that's so dangerous, it's the training regimen. It's the calorie deficit that results when a heavy exerciser eats too little in the mistaken belief that she'll perform better if she's unnaturally thin. She won't. According to endocrinologist Michelle Warren, M.D., head of the Center for Women's Health at St. Luke's Roosevelt Hospital in New York City, "If a woman isn't taking in enough calories to support her energy expenditure, her hormones will shut down anything that takes energy including bone turnover."

An evolutionary explanation comes from endocrinologist Ethel S. Siris, M.D., director of osteoporosis programs at the Center for Women's Health of New York's Columbia Presbyterian Medical Center: "Let's go back to cave-dwelling times. If a woman has to stay on the run fleeing ferocious animals, say, it's likely that she won't get enough to eat. If she's undernourished, it's not a good time to get pregnant. Therefore, her system produces less estrogen to make her infertile. Today, the very competitive runner is mimicking this early ancestor. As a result, the long-time suppression of estrogen production can affect both her fertility and her bone density."

The good news , according to Judy Mahle Lutter, president of the Melpomene Institute for Women's Health Research, is that this kind of problem does not exist for 95 percent of runners. Research data are reassuring for the ordinary recreational runner and also for the competitive runner who continues to menstruate.

In studies conducted by Dr. Stillman's kinesiology department, collegiate runners and gymnasts who exercised regularly but did not compete had higher bone density than either competing athletes or non-exercisers. Although some people face more risk than others (see "Are you at risk?"), all women including high-performing athletes with menstrual irregularities can do a great deal to minimize the risk of osteoporosis.

What not to do

If you smoke, stop now. Smokers are at higher risk for hip fracture, and smokers' bones heal more slowly.

Don't have more than two alcoholic drinks a day. Heavy drinkers lose bone faster than moderate drinkers or teetotalers, probably because alcohol inhibits calcium retention.

Don't drink more than two cups of coffee a day. Caffeine is a diuretic and increases the amount of calcium you excrete in your urine. Some research has shown that drinking milk in addition to coffee can help retard bone loss.

Don't overdose on protein. A high-protein diet creates an acidic blood content, which leaches calcium from the bones. Fifty grams of protein a day (about the amount in two 3-ounce portions of meat, chicken, fish, or cheese) is plenty for most people.

Don't stop running. Continue to run or to work out in such weight-bearing activities as brisk walking, skating, jumping rope, stair climbing, dancing, bicycling, and weight training.

What to do

If you have not begun to menstruate by age 16, or you have stopped menstruating for as long as 6 months, see your doctor right away. This is a danger signal that your ability to have children, as well as to continue to lead an active life, may be in peril.

Gain some weight. Train less or eat more until your menses resume. "This is what I always recommend first," says Dr. Siris. "But they never listen." Gordon Bakoulis, however, has listened. As health editor of Woman's Day Magazine, she is knowledgeable and willing to apply this knowledge to her own life. "I'm a 2:33 marathoner who has been running competitively for more than ten years. If someone at my level would consider giving up competition, I think this says a lot. I'm not about to give up running altogether, but I don't think that winning marathons is worth putting my bones at risk."

Check your calcium intake. For healthy bones, premenopausal women should be getting 1,000 mg of calcium a day; postmenopausal women, 1,500. If you can get this from dairy products (especially skim milk or nonfat yogurt) and other calcium-rich foods (like fish with soft bones that you eat, calcium-fortified orange juice, and dark green, leafy vegetables), so much the better. But since it's hard to get enough calcium from food, you will probably want to take a supplement. Calcium carbonate is the most popular and the least expensive and the one with the most usable calcium. Take it with meals, starting gradually to minimize gas or constipation. Drink fluoridated water, since there is some evidence that fluoride may help increase bone density.

Check your vitamin D intake. Either get 15 minutes of sunlight a day or take a supplement (400 IU in a daily multivitamin or in your calcium supplement).

If you seem to be at high risk for osteoporosis, ask your doctor if you should have your bone density measured. Bone density screening has been tested mostly on postmenopausal women and is less reliable for predicting fractures for women of other ages. Before going for the test, have your doctor check for any decrease in height or curvature of the spine.

If you decide on the test, you can undergo one of the new techniques that detect bone loss as low as 1 or 2 percent (an ordinary X-ray does not detect loss below 25 to 30 percent). The new methods are noninvasive, painless, take only about half an hour, and use very low doses of radiation. They are also expensive ($100 to $400) and often not covered by insurance, a situation that women's groups are lobbying to change.

The newest and most accurate method for measuring density of the hip and spine (the most common sites of fracture) is dual energy X-ray absorptiometry (DEXA). Single-energy X-ray absorptiometry (SXA) measures bone in the heel or wrist. Several other technologies are also used.

Talk to your doctor about whether you should take estrogenin oral contraceptives or a hormonal stimulant that induces ovulation if you are premenopausal, or as hormone replacement therapy (HRT) if you are in menopause or past it (you have not had periods for a year). Lost bone cannot be regained, but estrogen often slows or stops further loss. The Pill, of course, also provides the bonus of birth control. Also explore other therapies, like the new drug FOSAMAX or herbal and naatural remedies.
Estrogen is not advisable for women who have multiple risk factors for breast cancer, including having a mother or sister who had it; having begun menstuating earlier than 13 years of age or stopped after 50; never having had children or having a first child over 35; not having breast-fed; being obese; or getting a report of high risk from a breast biopsy. Other possible contraindications are a history of cervical or uterine cancer, blood clots, hypertension, heart attack, stroke, liver or gallbladder disease, or unexplained vaginal bleeding.

Be alert to safety hazards in your environment, especially as you grow older. Bone density is only one aspect of the risk of fractures. Preventing falls is another. All runners should pay careful attention to road conditions (especially in winter and on cross-country trails), running routes, and home layout.

Some women's health advocates believe that the "epidemic" of osteoporosis is a fiction fostered by pharmaceutical and technology firms, that women showing normal signs of aging are being treated as if they have a disease, and that, while some women do indeed suffer grievously from osteoporosis, more women are being treated more aggressively than they need to be. Other advocates are just as convinced that women are not being treated aggressively enough and that this is a sadly neglected area of public health.

As women, as runners, as health consumers, we need to educate ourselves. We need to look at how we and our daughters are running our lives, as well as our races. We need to question our coaches and our doctors. We need to weigh what they say and then to choose our own course. It's not always easy to know which path to take, but when we arm ourselves with information and with the will to win in life as well as at the finish line, the trophies we earn may well be our own lives.

Are you at risk?

You face a higher-than-average-risk of developing osteoporosis if you fall into one or more of these categories:

Are of European or Asian ancestry (women of African ancestry are at lower risk)

Have a fair complexion and blonde or reddish hair

Have a small-boned frame

Are of above-average height

Have experienced menstrual irregularities, especially the absence of menses for one year

Went through menopause, either natural or surgical, before age 45

Have a mother or grandmother who lost height or broke bones in later life

Have suffered from anorexia, bulimia, diabetes, kidney, or liver disease

Have used anticonvulsants, corticosteroids, diuretics, thyroid medications, or antacids containing aluminum

Have never been pregnant

Although you can't do anything about most of these risk factors, you can do a great deal to minimize your chances of suffering from osteoporosis, as described elsewhere in this article.

RESOURCES FOR LEARNING MORE

ORGANIZATIONS

Melpomene Institute for Women's Health Research, 1010 University Avenue,. St. Paul, MN 55104. 612/642-1915. Named for the first woman Olympic marathoner, this membership organization conducts and publishes research on active women.

Older Women's League (OWL), 666 Eleventh Street, N.W., Washington, DC 20001. 202/783-6686. Publishes A Status Report on Osteoporosis and lobbies for insurance coverage of bone density testing. 800-TAKE-OWL gives information on model state laws.

National Osteoporosis Foundation, 1150 17th Street, N.W., Suite 500, Washington, DC 20036-4603. 800/464-6700 Gives information about testing and treatment and locations of testing facilities near you. (The service is underwritten by a drug company.)

National Women's Health Network (NWHN), 514 10th Street, N.W., Suite 400, Washington, DC 20004. 202/347-1140. (Information clearinghouse: 202/628-7814.) Studies and speaks out on a variety of women's health issues. Its 160-page packet of reprints of articles about osteoporosis costs $8 ($6 for members) and a 49-page booklet, "Taking Hormones and Women's Health" is $10 ($9 for members). Both are highly skeptical about HRT.

Boston Women's Health Book Collective, 240A Elm Street, Somerville, MA 02144. 617/625-0271. Publishes Our Bodies, Ourselves and Ourselves, Growing Older, and gives information by mail and phone on women's health issues.

BOOKS

The Bodywise Woman, by the Staff and Researchers of the Melpomene Institute for Women's Health Research. (1996, order from Melpomene). This book looks at many aspects of women's lives as related to physical activity, including menstruation, pregnancy, child rearing, and aging. Its discussion of calcium intake and diagrams of exercises to strengthen bones are particularly helpful.

What Every Woman Should Know: Staying Healthy after 40, by Lila Nachtigall, M.D., Robert D. Nachtigall, M.D., and Joan Rattner Heilman. (Warner Books, 1995). This book pays a lot of attention to osteoporosis, mostly in post-menopausal women, and is strongly in favor of HRT. Women of any age can benefit from its tables on calcium content in foods, its sections on calcium supplements, and its descriptions of treatments for osteoporosis.

Sally Wendkos Olds has written extensively about child and adult development and health, and has won national awards for both her book and magazine writing. Her classic book, The Complete Book of Breastfeeding, offers suggestions for running nursing mothers; her coauthored textbooks, A Child's World and Human Development, the leading college texts in child development and lifespan development, both emphasize the importance of exercise in a healthy life. A member of the New York Road Runners Club, Sally has run and volunteered at the New York City Marathon, but not at the same time. Permission granted to redistribute, as long as you acknowledge the author, FootNotes and the Road Runners Club of America.