STUDY: Soaking Up Summer Sun Wards Off Winter Blues

You only have a few weeks left to stock up on Vitamin D! Getting enough sunshine in the summer keeps your serotonin levels high all winter and prevents seasonal depression, researchers find.


Vitamin D can be stored up when the sun is out and help keep you happy even when skies are grey, a new study out of Finland finds.

An adequate reserve of vitamin D helps the body maintain higher levels of serotonin that help ward off seasonal affective disorder (SAD) months later, say researchers from University of Helsinki’s National Public Health Institute.

The researchers already knew that seasonal depression could be improved by sunlight exposure, but they now know those benefits can be saved up for a rainy day (or season).

Mood is influenced by a complex web of relationships between sunlight, melatonin (the sleep hormone) and serotonin (the hormone associated with wakefulness and elevated mood), explains

Serotonin levels increase when you’re exposed to bright light — a major reason why moods tend to be more elevated during the summer.

This hormone is the basis of the most successful antidepressant drugs, which work by helping naturally produced serotonin stay in the bloodstream longer, keeping your mood and energy levels higher.

It is well known that bright-light therapy produces quick benefits for people with depression or SAD. In fact, some researchers are concluding that light therapy may help to alleviate SAD symptoms faster than antidepressant drugs.

However, few doctors have considered the possibility that sunlight exposure in the summer could impact how you feel months later.

Dr. Tim Partonen and his team found that getting more sun during the summer builds up a store of cholecalciferol that spurs vitamin D production during the darker winter months, which leads to higher serotonin levels.

Therefore, the amount of serotonin you have in the winter is determined by your sun exposure the previous summer, Partonen argues.

If you didn’t catch enough rays last summer, consider a supplement or vitamin D-rich foods, and go stock up on the sun every chance you get!