Go ahead and spend another hour on the beach-- it could improve your life in the bedroom. Experts say that vitamin D, which you get an increased dose of with sun exposure, changes your sex drive. Sexual health expert Aly Dilks tells The Sun that Vitamin D is known to stimulate the release of testosterone (in men), which is the hormone responsible for our sex drive. She adds, "Think back to caveman times, those men catching animals out in the sun all day still needed the energy to come back and procreate to save their race. This is nature at its rawest." At the same time, Vitamin D is known to increase levels of oestrogen levels in women, which in turn increases female sex drive.