Most people experience changes in their mood and behavior when the seasons change. You could call it "winter depression" but this transition in the amount of light is a signal to the animals, plants and people that the seasons are changing and can have a profound effect on your body chemistry. Some individuals notice a decrease in their energy levels and will require more hours of sleep. Other changes in behavior can be the isolation of family and friends or an increase in the consumption of foods and caffeine.
The strongest evidence of human seasonality comes in the form of winter depression or seasonal affective disorder (SAD - Seasonal Affective Disorder). Individuals with SAD usually suffer from depressive episodes beginning in the late fall or early winter and begin to feel better as spring or summer approaches. Living in a northern location with raw winters and extended darkness can affect your levels of melatonin, a hormone that impacts sleep. When the hours of the day decrease, melatonin levels increase, which can cause fatigue and depression for some.
The extended darkness also interrupts the circadian rhythm as the extended exposure to sunlight tells the body to fall asleep when it should be awake. Light provides environmental clues that influence pupil dilation, alertness, heart rate and melatonin levels. In fact, the light that enters the retina of the eye is actually what establishes the heart rate.
This response to the seasons can happen the other way around when the weather becomes warm and sunny and your body begins to receive a prolonged exposure to light. Some individuals experience insomnia or become more anxious, irritable and hyperactive during spring and summer. This condition is called reverse affective seasonal disorder (Reverse Seasonal Affective Disorder).
Each person's circadian rhythm is different, depending on their genetics and environmental circumstances. In addition, with increased urbanization, people tend to spend more time working in interior offices without windows than in the past. The lack of sunlight resulting from this can cause low body levels of vitamin D, serotonin and dopamine, which can affect brain chemistry.
Light therapy or phototherapy is extremely useful in relieving some depressive symptoms. The light treatment uses artificial lights to mimic exterior light, thus activating changes in the brain that can help raise serotonin and dopamine.You can also use sunrise simulators that mimic the sunrise to help you wake up without feeling dizzy. 30 minutes of daily exercise can also help balance brain chemistry and increase your energy levels. In milder cases of SAD, the addition of omega 3 fatty acids to an already balanced diet relieves some depressive symptoms. If you notice that you have a seasonal pattern of winter depression and you feel that your symptoms are severe, seek help from a professional. Try to keep a diary of behavioral changes to be able to give accurate information about your symptoms to the doctor. Practice a healthy lifestyle every day so you can enjoy every season of the year.