With all the bad press sunshine has received in the recent years, you would think the healthiest of all creatures would be moles, cave-dwelling bats, and coal miners. Indeed, certain cultures, have spent an inordinate amount of time seeking a deep tan, that, coupled with other poor health practices, leads to premature aging of the skin and certain cancers.
Life is as dependent on sunlight as it is on water. There are multiple reasons why it is so necessary for life. All warmth on earth came from the sun's heat-producing rays, without which all life would quickly freeze and die. The sun is a mega-powerhouse of energy, a portion of which is transferred to energy in the human body. Earth receives ten times more energy from sunlight than our planet's entire supply of fossil fuels each year.1 Plants require specific segments of the color spectrum or they will fail and die. A portion of the same ultraviolet (UV) light that causes tanning and sunburning is also responsible for producing vitamin D in the body. Incidentally, UV light does not produce vitamin D through glass, so sitting in a bright spot in your home will not help you get your daily dose.
UV rays from the sun change a chemical in your skin into an inactive form of vitamin D, which is then converted in the liver and kidneys to an active form of vitamin D.2 You need it because it is an essential nutrient that helps your body absorb calcium from the food you eat. In this way, the vitamin aids in maintaining healthy bones and muscles. The vitamin is also available through supplementation, but as with other nutrients, vitamin D is best when received from the most natural of sources, in the case, the sun.
This is not an excuse to throw caution to the wind, however. Doctors Dail and Thomas3 recommend a daily sunbath of no more than 30 minutes, which is sufficient for production of vitamin D. Healthy sun exposure takes into account time of day (never during midday), temperature, weather, altitude, time of year and your skin's sensitivity to being burnt. Use common sense. It is always a good idea to discuss your plans with your doctor, especially if you are taking medications. If you are not accustomed to sun exposure, and particularly if you are light-skinned, it is a good idea to start slowly, as little as three minutes a day until you are able to increase to the thirty minute maximum. Always keep the above factors in mind and keep your eyes closed during the sunbath.
Astronaut John Glenn once said,
"I don't know what you could say about a day in which you have seen four beautiful sunsets."
Not many of us will get to have such an experience in this finite life, but in the meantime we can enjoy a bit of sunlight every day knowing that, with a little caution, we are doing good things for our bodies.
Written by Sheryle Beaudry, RN,C, BSN -Copyright © 2000
1 The Handy Physics Answer Book, P. Erik Gundersen, Visible Ink Press, Farmington Hills, Michigan, 1999, 102
2 Principles of Anatomy and Physiology, Gerard J. Tortora and Nicholas P. Anagnostakos, Harper &amp;amp; Row, New York, 1990, 810
3 Simple Remedies for the Home, Clarence W. Dail, MD and Charles S. Thomas PhD, MMI Press, Harrisville, New Hampshire, 1985, 67