Maybe you love the return of the flowers and leaves in spring. Or maybe you enjoy the changing colors of the trees in autumn. Some people love all the outdoor activities they can do in the summer, while others prefer skiing and skating in winter. Whatever reason you have for your favorite season, people usually do prefer one over the others. What causes the seasons? And what are the effects of the seasons on health? Are there healthier seasons? Does the season of one’s birth affect their later health?
The Earth is tilted as it revolves around the sun. As a result, there are times when the Northern Hemisphere faces the sun more directly, and other times when the Southern Hemisphere is more directly in line with the sun. These differences cause the seasons, and are the reason why July is the hottest month in most of the Northern Hemisphere (when it faces the sun), but is the middle of winter south of the equator (pointed away from the sun).
On my Facebook page, I recently conducted a very unscientific survey of the seasonal preferences of friends and family. While the results were fairly mixed, overall there was a preference for autumn. However, recent larger surveys of Americans tend to affirm that the temperate seasons of fall and spring are favored, with a YouGov survey in 2013 showing fall as the favorite of more people, and a Gallup survey in 2015 showing spring as the favorite of the most people. Could the month of one’s birth have an impact on seasonal preference? While most report that their preferred season has the weather they enjoy most, this can differ from region to region. If you are from Florida, you might prefer winter, because a Florida winter is more temperate and most like spring or fall in the rest of the country.
Some scientific research shows that the season in which one is born might make a person more likely to be prone to mental illness. A study conducted at Vanderbilt University in 2010 demonstrated the so-called “imprinting effect”, at least in mice, in which the daylight one is exposed to during the early months of life has a lasting impact on the brain. This may help explain the greater levels of schizophrenia, depression and seasonal affective disorder in those born in winter. Conversely, babies born in May through June seem to be somewhat healthier overall.
Illness tends to rise during the autumn and winter months. In many cases, this is due to children returning to school and sharing germs with each other in close quarters, and then bringing those viruses back to home to families, who are spending more time indoors during the colder months. The drier indoor air during this time also makes people more susceptible to cold viruses. Flu tends to peak in winter as well for the same reasons. Regardless of the season, doctors insist that the best way to stay free of viruses is through regular hand washing, a good regimen of diet and exercise, and getting enough restorative sleep every night (usually 7-8 hours for most people).
And perhaps the sun itself plays a role in seasonal preference and health. Many people are deficient in vitamin D. The deficiency can cause a number of health problems, including muscle pain and fatigue, and may even play a role in multiple sclerosis and cancer. The easiest and most common way to increase vitamin D in the blood is through sun exposure. The body converts sunlight to vitamin D, which is then used for healthy muscle and bone. The active spring and summer months expose people to sunlight making these deficiencies decrease in summer and fall.
Whatever your favorite season might be, enjoy it!