Because our bodies have been designed to make vitamin D when our skin is exposed to UVB rays, I have been using a tanning bed during the winter months (I live in the Seattle area). This is controversial. Conventional wisdom is to avoid the sun and always protect yourself from its rays and to supplement with vitamin D instead. Itís a fact the rays damage DNA and most of this damage is caused by free radicals created by UVA rays. However, exercise also creates free radicals and I doubt anyone is going to tell me to stop doing that. Besides, your body has DNA repair mechanisms. If it didn't none of us would live long enough to reproduce. The important thing is not to do so much damage to your DNA that the rate of damage out paces repair mechanisms. This applies to UV ray exposure and exercise. In order not to overdo it these are my rules for using a tanning bed.

1) Use a cheap tanning bed. The expensive tanning beds emit fewer UVB rays because those are the ones that cause sunburns. UVB rays are also the rays your body uses to produce vitamin D.

2) DONíT GET TAN or get barely tan. The amount of UVB a person needs to make vitamin D depends on their skin type. I think my skin type is 3 (I am dark for Caucasian). By experimentation I have determined that I can use a tanning bed for 5 minutes (every other day) without getting tan. To make sure that I am not getting tan I donít strip all the way down so that a tan line will be visible if I do get tan. Once you start getting tan you will need more UVB exposure to produce vitamin D.

What do you think? Are there any other rules that you would suggest or would you argue against all use of tanning beds?