For female runners, all those miles can eventually do a number on your bone-density levels, says a recent report from the Journal of Athletic Training.

To help remedy this issue, you can do two things. The first, which is the one people suggest most often for issues related to bone health, is to make sure that you're getting enough calcium in your diet. If you're not a milk drinker, there are a number of other foods that contain a good deal of this nutrient, as do supplements. The second step you can take to help protect your bones is to start lifting weights.

Research from the University of Connecticut shows that resistance training can increae bone-density levels, as well as keep them close to where they should be as women age.