A coffee habit, coupled with regular exercise, may help prevent skin cancers better than either factor alone, new research suggests.

Both caffeine and exercise seem to help kill the UVB-damaged cells before malignancy sets in. "We really don't know how that happens," said Dr. Allan H. Conney, senior author of the study.

In the study, his team looked at four groups of hairless mice. The rodents' exposed skin is very vulnerable to the sun.

Four groups of mice were studied in the experiment. The caffeine drinkers showed a 96 percent increase in damaged cell death compared to the control group and the exercisers showed a 120 percent increase. Even more significant, the mice that drank caffeine and ran on the training wheel had a nearly 400 percent increase in cell death of damaged cells.

This is not a reason to skip out on sunblock, though. Learn more at livescience.