The existence of nearly all life on Earth is fueled by light from the Sun. Besides keeping us warm, there are a lot of health benefits associated with sunlight exposure. But while the ultraviolet (UV) radiation in sunlight provides a host of positive effects on our well-being, long-term sunlight exposure is linked to some wholly negative health issues. Similarly, a lack of sunlight can cause a multitude of problems. So, what are the signs that you're absorbing too much sunlight, and what is the dark side of getting too little?
Click through the following gallery and find out the effects of too much—and not enough—sunlight on human health.