Who would have guessed that coffee and exercise induce the formation of cells that block sunrays? But they do–at least in mice.
As reported in the Proceedings of the National Academy of Science, hairless mice who were fed high doses of caffeine, and exercised on their running wheels, showed an increase in the cells which protect against sunburn.
There have been no human studies to date, so you may wish to continue your sunscreen, hats and shirts before switching to double espressos on the beach.
Source: Proceedings of the National Academy of Science, "Voluntary exercise together with oral caffeine markedly stimulates UVB light-induced apoptosis and decreases tissue fat in SKH-1"