“Whoever wishes to pursue the science of medicine in a direct manner must ?rst investigate the seasons of the year and what occurs in them.” –Hippocrates
Humans are mammals, after all. Bears know to hibernate in the winter. Sheep know to breed in the fall and whales migrate to warmer waters in the fall. Around the spring equinox when the days and nights last roughly twelve hours, humans know to… turn their clocks ahead?
During the world wars, the United States and Great Britain began observing Daylight Savings Time to save electricity. Today, most areas of the United States except Arizona and Hawaii, opt-in to Daylight Savings Time. Since the human circadian clock is dependent on light (especially morning light) to dictate when to sleep, wake up, eat, and perform other bodily functions in the course of a day, the sudden change of a darker morning and an extra hour of light at the end of the day could keep one’s body in winter mode longer than is natural. This may contribute to imbalances in the biological clock, such as Seasonal Affective Disorder and sleep disorders.
Seasonal affective disorder (SAD) is a seasonal pattern of recurrent depressive episodes occurring in the dark months of autumn and winter, which often spontaneously remits in spring. The prevalence of SAD is between 1% -10% of the population and may worsen with latitude. A major theory for explaining SAD involves the circadian rhythms of the body. It is thought that in SAD, the internal clock becomes disrupted, leading to various symptoms such as depressed mood, weight loss or gain, decrease or increase in appetite, insomnia or hypersomnia, fatigue and diminished ability to think and concentrate. According to this theory, sunlight acts as a synchronizer of the circadian rhythms in humans, and exposure to artificial light, especially in the evening, can shift these rhythms out of phase. Melatonin levels, which should only be elevated at night, are often higher during the day in those who suffer from SAD. Exposure to bright natural light or full spectrum light during the day suppresses melatonin and can shift the rhythms back into phase, and for this reason light therapy is the first choice treatment for this population.
The change in seasons can also cause fluctuations in Vitamin D levels, which are generally higher in the summer and lower in the winter. A two-year trial of Vitamin D supplementation in patients with neurologic complaints who also had evidence of abnormal sleep revealed that Vitamin D is tightly linked to sleep. Levels lower than 40 ng/ml were found to be associated with sleep disorders. Improvements in neurologic symptoms and sleep were found in most patients when they maintained a narrow range of 25(OH)Vitamin D3 blood levels of 60-80 ng/ml. While people can make Vitamin D on their skin with large amounts of skin exposed (i.e.: legs and arms), most people cover up or wear sunscreen, necessitating Vitamin D supplementation to maintain the healthy range for sleep.
As bears emerge from hibernation and whales return to their home waters in spring, it’s time for humans to get on board with fellow mammals and follow the seasonal need to expose ourselves to natural sunlight. Circadian rhythms depend upon it!
Curious about melatonin levels. I have a panel for that! Add the melatonin panel to any hormone panel ordered to gain insight into ciradian melatonin levels, which may inform treatment considerations.
Call me for additional information Frank Nuber 636-278-6561 www.excelapothecary.com
505 Salt Lick Road.
Saint Peters, Missouri 63376