But, if you are 45 and a cyclist it probably would not be a bad time to start.

A year or so ago, there were articles out that endurance cyclists, including men, should be very careful about their bone density; apparently there were some studies where even though you are fit, you don't put enough pressure on the bones, not weight bearing enough, and you are depleting your body a lot with the endurance training - hence - low bone density.

It is also a good idea if you are a cyclist to help your bones by doing some weight lifting or weight bearing exercise so that you are building your bones, take calcium etc.

Also, I'm no expert, but I've heard that even if you have lower bone densities that you shouldn't give up on the weight bearing exercise, you can help your bones from degenerating as quickly and I've even heard you can stop the loss from increasing.

I'm 46 and had a bone density test at the age of 42. It wasn't because I'm good at having tests, but because my husband is an x-ray tech and he was using me as a guinea pig on his company's new bone density machine! Free tests! Yeah!