Wait -- could slathering on the sunscreen actually make you less healthy?

Image courtesy of U.S. Department of Veterans Affairs

We've been hearing about the evils of sun exposure practically from birth. It causes not only premature skin aging and sun spots, but also a much more formidable foe: skin cancer. With the dire warnings in mind, most of us apply sunscreen every day and seek out shade when we're outdoors, lest our skin come into contact with the sun's harmful UV rays.

As it turns out, there's another side to the story. Sun exposure isn't all bad. In fact, it's mostly good.

That's right: Sun exposure is good for you. After decades of avoiding it, researchers are finding that we may have been doing more harm than good.

It's a shock to the system, for sure, but the evidence is substantial. A chronic lack of sun exposure has been linked to fertility problems, several forms of cancer, general poor health and varying degrees of depression. People actually get depressed, with symptoms like sadness, fatigue and hopelessness -- from a lack of sunlight.

The form of depression most often associated with variations in sunlight is seasonal affective disorder (SAD). The disorder runs in cycles of depression and wellness that follow the seasons -- more specifically, the availability of sunlight. Someone with SAD might feel perfectly fine in spring and summer, and then experience a severe downturn in mood when fall hits. They'll stay that way through the winter, until the sun comes out again in full force. SAD is particularly prevalent in parts of the world with little winter daylight and/or extended overcast periods, like Alaska or the U.S. Northwest. In this article, we'll find out why sunlight exposure can affect your emotional well-being and how you can safely use the sun to benefit your mood.

As it turns out, humans aren't quite as removed from their natural instincts as some believe.