Indoor Tanning Beds
There are typically two types of indoor tanning beds you'll find at your local tanning salon, high-pressure tanning beds and low-pressure tanning beds. The dissimilarity between these two isn't in the beds themselves, but quite in the tanning bed bulbs they use. High-pressure tanning beds use high-pressure quartz lamps, whereas low-pressure indoor tanning beds use conventional low-pressure fluorescent tubes.
The main difference between high-pressure indoor tanning beds and low-pressure tanning beds is all in the UVA-UVB ratio. High-pressure tanning beds naturally produce a higher percentage of UVA, which encourages the skin to tan 6 to 8 times faster. The procedure works like this; high-pressure tanning bulbs emit just sufficient UVB to stimulate melanin production, and a lot of UVA which encourage oxidization of that melanin (giving us a deep golden tan color). As an added advantage high-pressure tanning beds decrease the risk of burning, since it's the UVB which causes sun burns.
So why doesn't everyone use high-pressure tanning beds? Some expert considers the high ratio of UVA to UVB isn't safe. UVA can still injure the skin and cause some forms of skin cancer, it can also harm the skin's agility. Most prominently, however, high-pressure tanning doesn't help at all with the one major health benefit of tanning - vitamin D production. To encourage vitamin D a higher percentage of UVB is needed, as is delivered with low-pressure tanning beds.