American scientists found that caffeine and exercise separately helped prevent the harmful effects of the sun but together they worked wonders and were even more effective in counteracting the danger of skin cancer.

Although the mechanism of the protection is not known yet, the scientists believe that it is some kind of synergy.

The tests were done on mice that were exposed to lamps that generated ultraviolet-B (UVB) radiation. The mice were divided into four groups. One group drank caffeinated water. Another group exercised on a running wheel, a third one drank caffeinated water and exercised and the fourth “control” group did not exercise or had any caffeine. The researchers then looked for evidence of apoptosis, the process by which damaged cells “commit suicide” to avoid cancer. Those cells that survive can turn into malignant skin cancers.

The results showed that in comparison to the control group, the mice exposed to caffeine that did not exercise showed a 95% increase in apoptosis while mice that just exercised without taking caffeine showed a 120% increase in apoptosis. The combination of caffeine and exercise caused a four-fold increase in apoptosis.

It is still needed to figure out how the combination of caffeine and exercise influenced cells and molecules and identify the underlying mechanisms.
Until further research is done, scientists are not advising drinking a cup of coffee before going out jogging as a substitute for adequate sun protection.