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I’ve been running off and on for about 10 years, and I recently became more serious about my running – I joined a team, set some goals and am becoming more consistent with my workouts. As a result, I’ve been increasing my mileage, and I’ve met some really great like-minded runners. Unfortunately, I’ve also encountered 5 women in the last 2 months who have suffered some type of foot fracture. These women range in age from 23 to 38; some have been running competitively since high school and others are relatively new to the sport. I’m hoping to avoid this seemingly common injury myself. What causes these types of injuries in women and how can I avoid them?
–Cindy, New York City
Well Cindy, it does seem like foot injuries are common. And it’s no wonder with all the pounding they take. But why do women seem especially prone? According to the American Academy of Orthopaedic Surgeons, women are more at risk than men for foot fractures thanks in large part to osteoporosis, irregular menstrual cycles, eating habits and other conditions that can decrease bone mass.
Many fractures are caused by overuse. And stress fractures—tiny cracks in your bones—are a common type. As runners, we definitely put our feet to work. According to the American Academy of Orthopaedic Surgeons, distance runners are especially prone. When our muscles tire, they’re unable to absorb the shock of each step and in turn, our bones begin to bear the burden paving the way for a stress fracture.
You’re most at risk if you increase any of the big three during your training: frequency, intensity and duration.
So if you’re planning to up your game, be sure to do so with care. Most experts recommend adding no more than 10 percent of your usual mileage per week. The same goes for time.
A commonly cited study from Australia concluded that over 40 percent of competitive female runners get stress fractures. The study also found that women with infrequent periods are six times more likely to have stress fractures. And women who restrict their diet? They’re eight times more likely. And it’s all interrelated.
Limiting food can stop menstruation, which in turn prevents your body from producing estrogen. And like calcium—the bone-boosting powerhouse that helps prevent osteoporosis, which can lead to painful fractures—estrogen is also crucial to bone health in women. How do you know you’re at risk? The intensity and frequency of your periods should be a good indicator.
Yet, another possible culprit might surprise you.
Deena Kastor—the American women’s marathon record holder and 2004 Olympic bronze medalist—famously fractured her foot while running the 2008 Olympic marathon in Beijing. The cause? A vitamin D deficiency.
We all know we’re supposed to get lots of calcium: 1,000 to 1,300 mg a day for women (1 cup of milk has 300 mg). But vitamin D is also crucial to healthy bones. Without it, our bodies can’t absorb all that calcium. So even if you’re getting enough calcium, it won’t do you much good if you’re not getting enough vitamin D.
It’s a problem most people don’t even know they have. A whopping 75 percent of Americans are vitamin D deficient, according to a March 2009 study by a group of doctors from Harvard, Johns Hopkins and University of Colorado. What’s more, runners don’t fare any better despite our extra time outdoors. A study out of Dallas found that 75 percent of runners are also low on vitamin D.
So how do you know if you’re getting enough? Only a blood test will tell you.
D-lightful and D-licious
So how can you make sure you get enough vitamin D? Let the sun in—10 minutes a day may be enough to get the D your body needs, according to the Mayo Clinic. But again, just because you run outside doesn’t mean you are necessarily getting a healthy dose. The winter sun in the north isn’t always strong enough to produce the amounts we need. How much? 200 to 600 IU per day, increasing as you age, though many doctors are calling for those levels to be raised to as much as 10,000 IU.
Not surprisingly, the American Academy of Dermatology advocates getting vitamin D from your diet. They even released an updated position paper in July in light of the spate of recent findings on vitamin D, stating there is no “safe threshold” of sun exposure “without increasing skin cancer risk.”
And if you’re like me—fair, freckly skinned, blue eyed, with a family history of skin cancer—aiming for unprotected sun exposure may not be such a great idea. I love my sun block and I’m pretty sure it loves me back.
So consider taking a daily vitamin D supplement and eat vitamin D rich foods. Mushrooms and fatty fish, like salmon and tuna, are great sources. And many products like milk, orange juice and cereal are fortified with an extra dose. The National Institute of Health has a good list of D-rich foods. And for a great article on vitamin D and it’s benefits check out Runner’s World.
How to avoid foot fractures
The one-two punch of overuse and vitamin D deficiency is a recipe for foot fractures that most runners face. Throw in low estrogen levels, as commonly found in female athletes, and you’ve got a trifecta why women are so prone to foot fractures and the conditions—like osteoporosis—that can cause them.
Thankfully, the American Academy of Orthopaedic Surgeons offers these tips to help you keep stress fractures at bay:
- Eat a healthy diet rich in calcium and vitamin D to help fortify your bones.
- Don’t wear old or worn running shoes.
- Cross train to prevent overuse. Swimming and cycling are good choices.
- Start new activities slowly, and gradually increase time, speed and distance; a 10 percent increase per week is ideal.
- Strength train to help prevent muscle fatigue and bone density loss that comes with aging.
- If pain or swelling occurs, stop running and rest for a few days. If pain continues, see your doctor.
The moral of the story is that when it comes to foot fractures, our bodies are only as strong as the weakest link. From the inside out, “you are what you eat” has never been truer. So ladies, eat enough food to keep your estrogen pumping and make sure your meals are rich in calcium and vitamin D. Increase the intensity of your workouts gradually, and hopefully you can keep the doctor away.
The Running Nerd
Do you have a question? I’ll find answer. Let my fingers to the walking, er running, for you. Contact me here: Contact Karla Bruning or post below.
Karla Bruning is host of On The Run, New York Road Runner’s weekly lifestyle web show about running. She has completed six marathons, two triathlons and trains with the New York Harriers. Follow Karla’s “Notes From a Running Nerd” at RunKarlaRun.com, Facebook and Twitter@KBruning.