The Amount of Sun People Receive Affects Their Mood
A young woman lies asleep on a cold, overcast winter morning. At 4 A.M., a faint incandescence radiates from a light bulb placed near her bed. The light gradually gains intensity and covers until 6 A.M., when the woman awakes. She had just experienced a simulated dawn of a new day. After being treated with this for several days, the woman's annual winter depression slowly goes away. Does this mean that the less sun you get the worse you feel, or perhaps the more you get the better your mood? It is very possible that you may feel this way as millions of people worldwide have experienced it first-hand. This phenomena is still sort of a mystery as many researchers don't completely understand why this happens. "It may be that certain individuals have inherited vulnerability that causes them to develop depression in the absence of exposure to sufficient environmental light"1. Frederick A. Cook, the arctic explorer, provided a vivid description of the effects of prolonged darkness on the human psyche: "The curtain of blackness which has overfallen the outer world has also descended upon the inner world of our souls," Cook wrote in his journal on May 16, 1898, "Around our tables . . . . men are sitting about sad and dejected lost in dreams of melancholy. For brief moments some try to break the spell by jokes, told perhaps for the 50th time. Others grind out a cheerful philosophy; but all efforts to infuse bright hopes fail."2 Some believe that light affects the body's ability to make serotonin, a neurotransmitter that helps induce feelings of calm and well being. The eye's sensitivity may also play a part in sun/mood relations. A study was done to a group of people in the winter and summer. In the winter the many individuals experienced much more difficulty seeing dim light after sitting in the dark for a while.3 Another study done in Vancouver shows that electrical activity in the retinas when a bright light is shone, is significantly less in winter4. As much as 5% of Americans suffer from Seasonal Affective disorder, also known as SAD5. SAD is an illness in which the sufferers feel depressed, feel lethargic, and they overeat . There is no known cause for this widespread illness. Many researchers of SAD are speculating on the idea that SAD patients might have seasonal variations in their melatonin secretions. A study of melatonin patterns in SAD sufferers was done to determine if melatonin was a factor in the disorder. Since mostly women are affected by SAD, researchers used healthy women as the control. The researchers who found that the significant difference in winter and summer pacemaking that occurred in SAD patients also saw similar patterns in the healthy women. Other studies show that a SAD sufferer's eye usually does not take in as much sunlight in the winter as a normal person, which may exaggerate the depression and other symptoms.6 Most SAD patients treated with light therapy for a few weeks usually lose the depression. SAD patients that tended to eat more than one portion of sweet things (such as chocolate, cake, or ice cream) per day usually found temporary relief from their illness.7 Swiss scientists believe that the sweet foods seems to "trigger" the release of the same mood-altering substances that light triggers. Nevertheless, light -- or lack thereof -- can really get under our skin. For instance, "Rapid changes in the day length greatly modify the daily cycle of sleep and melatonin secretion," report researchers led by psychiatrist Thomas A. Wehr of the National Institute of Mental Health, ". . . brain mechanisms that detect and respond to seasonal changes in day length may have been conserved in the course of human evolution."8 The findings with the sun's affect on humans matched those already observed in rats. Many of us have not yet realized what an important factor light is in our daily life. "Light is a complex stimulus that has been inadequately specified, given the intense clinical experimentation of the last five years."9 Research with these results easily prove that the sun and light really do alter our mood, and have a great influence on our lives.