Light is a pretty big deal. I think it’s something we know without even looking at the science of it. Think back to our most recent winter season. Remember driving to work in the morning while it still was dark outside. Again, when you drove home, it was dark outside. For most of us, that is a big bummer. It becomes an even bigger bummer when you did not take the time to get out of your office and head outside for a bit throughout the day. When the wind chill is somewhere south of zero, it is difficult to make a case for getting outside.
Yet, that’s what I’m going to do. No matter the season, we can greatly benefit from the rays of the sun. From brains to bones, the sun plays a key role in keeping us healthy. According to licensed psychologist Dr. Stephen Ilardi, author of The Depression Cure, the retina of the eye contains cones (for color), rods (for light and dark) and specialized light receptors for bright light. These bright light receptors communicate with the center of the brain where the circuits that control your energy levels and what we refer to as our body clock, as well as the circuits that contain dopamine (the neurotransmitter that helps control the brain’s reward and pleasure centers) and serotonin (the neurotransmitter that helps control mood) are located. Without question, we want these circuits to work well. If they don’t, our sleep suffers, our energy sags, our appetite can get out of control, we tend to want to hibernate, and hormone levels get out of balance.
When this happens, it means our circadian rhythms are out of sync. “Circadian rhythms are biological, mental and behavioral changes that follow a 24-hour cycle and respond to light and darkness within an organism’s environment” (Psychology Today, June 2013). When we take in an appropriate level of light, our circadian rhythms work well for us. Our sleep-wake cycles are consistent, we have proper hormone release, our body temperature is where it needs to be and many other bodily functions work as they should.
Another amazing quality of sunlight is that it works with our bodies to create vitamin D. When the sun’s UVB rays hit the skin directly (cannot be through a window or other type of glass), they interact with the cholesterol just under the skin to produce pre-vitamin D. Vitamin D gets generated through a process of events involving our blood, liver and kidneys. An adequate supply of Vitamin D in our bodies allows us to better absorb calcium and phosphorous, which are essential for bone strength. Vitamin D actually is a hormone that acts like a key that unlocks hundreds of genes that control day-to-day functioning of your brain, heart immune cells, bones, skin, nerves and blood vessels.
What is enough light? According to Dr. Ilardi It is recommended that we get a dose (30 minutes) of at least 2500 lux a day to keep our body clock in order. The brightest of indoor lighting is about 500 lux. Sunlight from a partly cloudy day is about 10,000 lux. For most of us, the best time of day is shortly after waking in the morning. Below is a diagram that shows the time of day it may be best for you to take in your daily does of sunshine.
If you simply are unable to take in enough sunlight – especially during those short, gloomy days of winter, you may want to consider a UV light box. These are used widely to help relieve the symptoms of depression and low levels of Vitamin D.
Take charge of your physical and mental health. If you catch yourself feeling a bit sluggish or down, the best remedy may just be right outside your front door.