Sunlight is a gift from God. As is true for all the natural remedies it must be received in moderation. We can get too much! (sunburn and skin cancer) Its availability varies with the season, latitude, and climate. Sunlight has both physiological and psychological effects. Who has not experienced the depression that accompanies many short, rainy, winter days and the lifting of our spirits when “the sun comes out?”

Vitamin D: Vitamin D is essential for the absorption of calcium and its utilization in the formation and maintenance of bone. The role of sunlight in its formation does not have to be understood to appreciate its benefits. The active form of Vitamin D is formed by the liver and kidneys from a precursor made in the skin when exposed to the appropriate wavelength (UV-B) and intensity of light. This wavelength is absorbed by the atmosphere and little reaches the earth’s surface in the morning and afternoon. A rule of thumb is that if your shadow is longer than your height little vitamin D precursor will form in your skin,

The darker your skin the longer it takes to get the needed vitamin D benefit. Caucasians can receive an adequate response in 15-20 minutes exposure to arms and legs 3 times a week, but Blacks require 2 or 3 times that. Older people also require more because the skin’s capacity to respond decreases with age, When we consider that so much of our time we spend indoors and clothed (especially as we get older) we may need to take vitamin D supplements. For these reasons, it is a good idea to have blood levels of vitamin D checked especially as we get older.

Vitamin D contributes to our health in many other ways see: https://www.health.harvard.edu/staying-healthy/time-for-more-vitamin-d

Hormones: Besides vitamin D there is another benefit moderate exposure to sunlight has on our bodies. The daily rhythm of light and dark has much to do with our sense of wellbeing. Sunlight induces the formation of serotonin, a mood enhancer helping us to focus calmly on our daily responsibilities. On the other hand, darkness triggers formation of melatonin, a hormone that promotes restful sleep. To reap the most benefits from these relationships it is important to establish and maintain a regularity of times to retire and rise. Sleep is most beneficial when we go to bed on an empty stomach. This means that the last meal of the day should be 3-4 hours before we retire. When we do that it is easy to fast for 12-14 hours each day. There are many benefits of following such a lifestyle (see https://www.health.harvard.edu/blog/intermittent-fasting-surprising-update-2018062914156)

https://www.healthline.com/health/depression/benefits-sunlight

In the Home: We spend most of our lives indoors. We now know that the more sunlight we let in the better off we are. Most home makers know that furniture and carpets that are regularly exposed to sunlight will fade. Their brilliant colors are lost. For that reason, many homes are kept dark by drawing the blinds or shades. This is unfortunate for the light that is excluded could bring multiple benefits. In addition to the effects of light on mood it reduces the bacterial burden in the home (see https://www.bustle.com/p/sunlight-can-help-kill-germs-in-your-house-a-new-study-says-12637741) So during the day open your home to let the sunlight in and at night open your bedroom window to let fresh air in. Both light and fresh air promote health.