Many bodybuilders tanned to have a more bronzed skin tone. Doing so can help their muscles look more defined. It also helps them feel better about themselves and feel more confident in their body.
Tanned skin is also an indicator of health, which is important for competitive athletes who want to look healthy for competitions.
The best way to get a tan is to wear a lot of sun block. A good sunscreen should be used on areas of the body that will be exposed to the sun for long periods of time during the day.