Long-Distance Runners Risk Bone Loss
Women Runners Must Eat Well, Add Other Exercise
Jan. 27, 2003 -- They seem to be at the peak of health. But young female long-distance runners risk bone loss, a British study confirms.
Running is good for you. It reduces the risk of heart disease, diabetes, and obesity. It once was thought to increase bone density -- but that's not necessarily so. Recent studies show that women who run long distances have lower bone density than women who just sit around. That's not good. Low bone density is a sign of osteoporosis and high risk of bone fracture.
How can this be? That's what a research team led by Melonie Burrows, PhD, lecturer in sport and exercise physiology at the U.K.'s University of East London, tried to find out. They enrolled 52 women runners, age 18-44, in an intensive study. The women ranged from recreational endurance runners who ran only five kilometers a week to elite athletes who ran 70 km a week. The average woman in the study ran eight hours per week and covered 32 km. They were also questioned to evaluate the possible effect of eating too little might have on bone loss.
The result: The women who ran the most had the lowest bone density. Each extra 10 km run per week was linked to 1% to 2% lower bone density. Women who had more muscle lost less bone, but the most muscular women were not those who ran the most. The study appears in the British Journal of Sports Medicine.
"If runners aren't taking on board enough energy, they tend to have bone [loss]," Burrows tells WebMD. "Women must eat properly. Is it the muscle mass that is the main thing to promote bone? When you look at women who play high-impact sports such as gymnastics and rugby, they have very high bone density -- more than runners. So it might be that muscle mass is the predominant factor influencing bone growth."
This makes a lot of sense to Peter W.R. Lemon, PhD, director of the exercise nutrition research laboratory at Canada's University of Western Ontario.