It has been gray again this winter. In the Pacific Northwest, we often get surprised by occasional sun shine and think about  how long we have not seen bright light. How does the lack of exposure to sun affect us?

Our body makes Vitamin D when we are exposed to the ultraviolet B (UVB) rays in sunlight. In order to have enough vitamin D in our body, 5-30 minutes twice a week of exposure to sunlight is recommended depending on where you live and the time of the year. We need Vitamin D to absorb calcium for strong bones. We live north of  47-degrees latitude, where we have a difficult time getting enough vitamin D from the sun from November through February. Vitamin D is also found in oily fish like tuna and salmon as well as in fortified foods like milk and breakfast cereals.

Every morning do you have to force yourself to wake up? Is it very hard? Our body thinks it is still nighttime. Dr. Jim Phelps, a psychiatrist who lives in the state of Oregon recommends using Dawn Simulator. It is an alarm clock with bright light which increases in intensity gradually in the morning and helps you to wake up naturally. Then exercise and get natural light as much as possible. Taking a walk in the natural light should be helpful. I like  to get exposure to intense light from a light box every morning while eating breakfast. It is so bright and reminds me of sun on tropical beaches.

If you feel fatigue and lack energy or feel depressed, it is possible that you may be experiencing Seasonal Affective Disorder(SAD). SAD is a type of Mood Disorder and should be diagnosed by qualified professionals. Why does the lack of exposure to sun cause SAD ? There are different theories but none of them has been universally accepted in the therapy community.

The Harvard Health Letter discusses three theories:

1. The root cause may be insensitivity to light. Most of us go through winter on a relatively even keel because exposure to indoor lighting helps offset the lack of natural light, but indoor light may be too weak for SAD sufferers.

2. There are neural pathways from the eyes’ retinas to parts of the brain that help put many of our physiological processes on a 24-hour cycle. Lack of light may put people with SAD out of phase with their biological clocks: awake and active when their internal timers want them snug in bed.

3. A lack of light, or insensitivity to it, may disrupt brain processes influenced by serotonin and dopamine, brain chemicals that play a role in mood.

Light Therapy Resource by Jim Phelps, MD.http://www.psycheducation.org/depression/LightTherapy.htm