Too Much Endurance Exercise May Reduce Bone Density

Want to strengthen your bones? Buy a jump rope. Want to weaken them? Become an endurance athlete, says a new bone study.

... Too much endurance exercise, it appears, may reduce bone density. In one small study completed by Dr. Barry and his colleagues, competitive cyclists lost bone density over the course of a long training season. Dr. Barry says that it’s possible, but not yet proved, that exercise that is too prolonged or intense may lead to excessive calcium loss through sweat. The body’s endocrine system may interpret this loss of calcium as serious enough to warrant leaching the mineral from bone. Dr. Barry is in the middle of a long-term study to determine whether supplementing with calcium-fortified chews before and after exercise reduces the bone-thinning response in competitive cyclists. He expects results in a year or so.

In the meantime, the current state-of-the-science message about exercise and bone building may be that, silly as it sounds, the best exercise is to simply jump up and down, for as long as the downstairs neighbor will tolerate. Read more