As the days get shorter, but the warmth of summer remains, the sun reminds me how grateful I am to live in the South. I wasn't always able to enjoy it.

Twenty years ago, I was in northern Indiana, just finishing up my internship and beginning my Post-Doc Residency. If you've never lived through a northern winter, imagine the coldest, snomaggeddon-ish days we have ever had -- lasting about 5 months. Yeah.

For a southerner, it was quite a shock. This time of year, the days were getting short and we were already having frosts! Though I try to see the benefit and the lesson in everything, my brief time as a northerner was a tough one. I just wanted to get back to the warmth. Wintertime meant leaving my apartment in the morning in the dark, returning after work in the dark.

And then a friend and fellow intern said, "I think God put me here so that I could learn what depression really is like." I certainly did get to experience a bit of Seasonal Affective Disorder (SAD), myself. I came to have a new appreciation for what my clients experience. It is why I cherish the sunny days and strongly encourage my clients to get out and get some sun when you can.

Sunlight has a balancing effect on mood and sleep cycles. Its role in Vitamin D production is well-documented, but only in recent years has medicine fully realized Vitamin D's importance as a key brain hormone. Vitamin D is crucial for the production of serotonin - the mood molecule that helps calm and focus us, and improve willpower. Low levels of Vitamin D and serotonin can lead to neuropsychiatric disorders, including depression and insomnia. Mercola reports that an estimated 30-50% of people have a Vitamin D deficiency, which is staggering when you think how easily this can be remedied.

There are Vitamin D supplements and food sources, but the best source is natural. Sunlight is best; and it is plentiful and free! Spending your days indoors under fluorescents, staring at artificial light screens is not healthy. If time is short (and for whom is it not?), plan your daily sunlight dose with something else you needed to do anyway, like exercise, lunching al fresco, or even taking calls while standing outside. Of course, stop short of burning.

You won't regret making serotonin while the sun shines!