It’s getting colder, and the days are shorter.
Seasonal Affective Disorder (SAD) is a type of mood disorder that happens when the seasons change. It’s classified as a seasonal pattern by the DSM-5, a general phenomenon that sees people become moodier and more tired as they go into the winter months.
Our circadian rhythm already undergoes changes due to the shorter daylight hours, which affects our sleep and mood by altering our summertime levels of melatonin and serotonin. The thicker, warmer clothes we wear also block the skin from getting enough sunlight, which interferes with its ability to produce vitamin D – a vitamin that 75% of Americans are deficient for.
Vitamin D deficiencies have been linked to poorer immune systems, weaker bones, chronic fatigue, and possibly mental health complications in the forms of depression, dementia, and schizophrenia. This might reflect a societal bent towards staying indoors and not receiving adequate amounts of natural light, since all it takes is about 15 minutes of direct sun exposure on your face, arms, and legs to fulfill your daily requirements for the D. Longer periods of indirect exposure (i.e., you sitting in the shade) will still meet your needs while minimizing your exposure to UV radiation.
The good news is that vitamin D deficiencies are easily corrected (supplementation is cheap, sunlight is free) and may yield some pretty cool ancillary benefits as well. Athletes from the Northern UK, a perpetually overcast region that receives little sunlight, supplemented with vitamin D demonstrated faster sprint times and higher vertical jumps. Even non-athletes who took vitamin D managed to increase their performance in sprinting and jumping over eight weeks.
I’d also invite you to take a look at your daily schedule. During the peak of summertime, sunset in Dallas didn’t happen until about 9:00 p.m. sometimes; today it’ll happen closer to 7:00 p.m. – which means that everyone’s experiencing what is essentially low-grade jet lag while this new light/temperature thing is being figured out. I’d ask you to let us know what you think on our Facebook page, but maybe you should get some sleep instead.