Cycling and osteoporosis

There have been some recent threads over at http://www.bikejournal.com dealing with the above (although unusually, no links provided). On the surface it appears an unusual combination, after all, exercise is supposed to prevent osteoporosis in later life. However, this apparently is not necessarily the case. While everything that comes from the press should be take in with a grain of salt in this day and age, it's worth learning some lessons from it if only for general health reasons. Evidently road cycling isn't considered a "weight-bearing" exercise because it doesn't put any strain on the joints (they should come and ride some Queensland "roads"). It also follows that mountain biking is considered to be a load-bearing activity.

I've always considered my love of milk and cheese (among other things) to give me an advantage in this area, but apparently ingesting calcium, in itself, isn't enough. Evidently a person also needs Vitamin D to fully draw the benefits from calcium, much like iron is needed to gain the maximum advantage from things like protein and carbohydrates. Now this shouldn't be a problem, after all, the strongest source of Vitamin D is direct sunlight. This is something most cyclists (and especially long distance cyclists) should get plenty of.

On the other hand, there are some who suggest that all of the sunscreen that people wear here could be an issue, so there seems to be a balancing act: getting enough sunshine to draw a substantial amount of Vitamin D, but not so much that we all die of skin cancer. The recent tactic I've adopted is that the sunscreen goes on at 9am, but prior to this (and indeed late in the afternoon), I get my sun exposure. I see this as the solution to the balancing act, I want to be doing this for long enough to ride a million kilometres.