Weather changes affect our productions of melatonin and serotonin, which heavily impact our mood and energy levels. The contrasts between our mood patterns in the summer and in colder seasons are strongly associated with sunlight levels and vitamin D exposure.
Variation in temperature requires different energy levels from the body in order to maintain body temperature. In cold weather, the body uses more energy to conserve body heat; this causes the common lack of alertness and constant craving for carbohydrates we tend to undergo on colder days. Carb-loaded foods are a good source of fast energy, but like a sugar crash, carbs cause fatigue and moodiness once the energy wears off. Maintaining healthy eating habits is the most effective way to overcome winter fatigue and decrease production of melatonin. Conserving body heat also imposes pressure on the immune system and allows it to be more vulnerable to viruses and bacteria; this explains why we tend to get sick in the winter more than summer. The lack of energy also hinders the immune system’s ability to completely fight off a sickness causing us to, consequently, face more fatigue and moodiness during winter.
Sunlight affects hormone production in the human brain, which affects energy level and mood. Serotonin, a neurotransmitter found most commonly in the nervous and digestive systems, is produced in higher quantities when sunlight exposure is prominent. The hormone is released by nerve cells in digestive organs to regulate food processing in the body. It also plays a major role in the nervous system; anxiety and mood are generally regulated by this neurotransmitter. High levels of serotonin are an indicator of what we consider a good mood and a feeling of happiness, while lower levels indicate a bad mood and even depression. Many psychiatrists treat depression with serotonin supplements rather than use techniques that will train the patient’s brain to naturally produce the hormone. While supplements improve the patient’s mood and increase serotonin levels in the body, its long term effects may be costly.
Seasonal Affective Disorder is a type of depression that occurs during certain seasons. People with imbalanced levels of serotonin tend to be more prone to this disorder. There is a fine difference between this disorder and what we call ‘the winter blues.’ About four to six percent of people in the US are diagnosed with SAD while the rest may suffer from sporadic low levels of serotonin and high melatonin production. The winter blues are easier to treat; staying active, spending time outdoors and staying warm help decrease the production of melatonin and thus eliminate the fatigue and sadness we usually feel during cold winters. Vitamin D, commonly acquired through the body’s absorption of sunlight, reduces melatonin production; so the more sunlight you are exposed to, the less melatonin you will produce. Lower levels of melatonin indicate more alertness and less fatigue and are thus more common in the summer, where sunlight level reaches its annual peak. While winter tends to be primarily associated with sickness, sadness and fatigue, the seasons during which SAD occurs depends on the individual. Symptoms are relatively standard among patients throughout the seasons: sadness, negativity, overall loss of interest, insomnia or oversleeping and weight gain. Typically, Seasonal Affective Disorder is treated using a light therapy method, which focuses on exposing the patient to more sunlight and vitamin D to stimulate a decrease in production of melatonin and thus gradually eliminate the symptoms.