Milk's reputation as the drink of choice for healthy bones was established years ago with the help of doctors and educators who touted it as a calcium-rich source, but lately, recent news has suggested that there are other ways of developing--and maintaining--high bone density, which is great information for non-milk drinkers.

Bone density, in case you're wondering, refers to the strength of the body's skeleton. Healthy bones are denser and contain more calcium than their unhealthy counterparts. And the stronger the bones, the less susceptible to injury one is. Because women over 30 begin to lose bone density as a matter of course, it's especially important that they take care of their bodies' internal structures and actively work to increase bone mass. Losing bone calcium leads to brittle and frail bones, which can then lead to osteoporosis or bones that are bound to break easily.

Those in favor of dairy continue to argue that "milk is the perfect vehicle to transport calcium to bones," according to a story on WebMD, but in a piece for the Times, Gretchen Reynolds discusses the importance of high-impact exercise without ever once mentioning milk. Reynolds points out how "past experiments have definitively established that subjecting bones to abrupt stress prompts them to add mass or at least reduces their loss of mass as people age." So how much force is necessary? And what can people do to apply that necessary working force?

Well, for starters, jarring activity (movements that literally impact the bones in a forceful manner) is key. Sprinting, jumping rope or simply hopping up and down "10 times twice a day," are physical activities that contribute to building bone mass. The reason has to do with g-forces, which is a measure of impact. In a study discussed in the Times piece, volunteers who experience over four Gs "had notably sturdier hipbones." Researchers are taking that information to try and see how much force below four Gs is efficient for adult maintenance of bone density--if anything below four Gs is helpful at all. When the force drops too much, the impact of the exercise moves from high to low, and so far, the research doesn't suggest that low-impact exercise aids in building bone density.

The study's finding gets tricky for people who haven't been exposed to high-impact exercise in a long time but who are, nonetheless, eager to build stronger bones. Beginning any exercise routine when you've been mostly stationary is extra challenging and something that shouldn't be undertaken without the consultation of a doctor. High-impact exercise is likely to represent even more difficulties for those unaccustomed to regular physical exertion. With frankness, Reynolds writes: "Their bodies and bones may not be capable of handling the types of activity most likely to improve bone health."

Once you've spoken to your doctor and have been given the green light to begin a high-impact exercise routine, consider going for a run!

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