Mankind knows that the sun is the centre of the universe and that it sustains life. But some ancient civilisations were a little confused: did the sun go around the earth? Or was it the other way around? All of them (the Chinese, Aztecs, Greeks, Romans and Indians) respected the sun and had elaborate rituals to appease its mighty power. Many of these movements were later incorporated into exercise forms, to be performed early in the morning clad in scanty clothing as the first rays of the sun appeared on the horizon.
The sun emits light with varying spectra. The UVB (the B band of ultra violet rays) stimulates the production of vitamin D. These rays are maximal at sunrise and sunset, when the sunlight hits the body at an angle, and not when the sun is directly overhead. The beneficial rays are also screened out by window panes, clouds, fog and smog. This is why exercise is best performed outdoors and at such times.
As the sunlight falls on the skin, it helps the body manufacture vitamin D. In 30 minutes, around 3000IU (international units) of vitamin D is formed and absorbed into the body. Vitamin D is essential for calcium to enter our bones. This prevents rickets in children, and osteoporosis and osteomalacia in adults. Most people require only five minutes of exposure to obtain their daily requirements of this important vitamin.
Many people take vitamin D supplements or capsules of natural cod liver oil to prevent a deficiency. But these rarely contain more than 90IU while children require 200IU/day and adults 400IU/day.
Sunlight affects the pineal gland in the brain and exposure reduces the formation and release of a hormone called melatonin. An increase in melatonin levels leads to depression. That is why the “blues” set in (even in tropical countries) during winter when the days are shorter, or during the dark cloudy monsoon days. Post-natal depression too is aggravated in women confined indoors in dark rooms after childbirth.
Regular and longer exposure to sunlight elevates the mood naturally. People who walk or jog outdoors in daylight regularly have a more positive approach to life, less stress and better ability to cope. Roman gladiators were exposed to the sun regularly as part of their training. The trainers discovered that this toughened them mentally, and enlarged and strengthened the muscles, giving them an edge over their opponents.
Fretful children, who sleep poorly, build up fatigue and tension in their hapless parents. These children will sleep longer and more soundly if they are exposed to sunlight between noon and 4 p.m. in the veranda or some other shaded area.
Sometimes babies are jaundiced after birth. Whatever the cause, exposure of the affected unclothed baby to sunlight (UVB) for 10 minutes daily, early in the morning, brings down the jaundice. In severe cases (in intensive care facilities and nurseries), infants are exposed to artificial UVB lights for longer periods to produce the same effect.
The incidence of certain cancers, like those of the breast, prostate, reproductive organs and colon, is increased in individuals who are not regularly exposed to the sun.
The sun is a good antiseptic. Before the modern antibiotic era, fresh air and sunshine were used to heal wounds and treat tuberculosis.
Bed bugs can be eliminated by regular exposure of mattresses and linen to sunlight. This prevents human exposure to toxic chemical pesticides.
In resource-limited settings, where fuel is scarce and expensive, families often consume contaminated water without boiling it. This causes diarrhoea, eventually leading to chronic ill health and malnutrition. Exposure of the water to sunlight in transparent plastic drums for an hour significantly reduces the bacterial load and the incidence of diarrhoeal diseases.
Beneficial sunlight enters our body through our eyes. It has a profound effect on hormones, reproduction and our natural internal circadian (sleep) rhythm. The amount allowed inside is naturally adjusted (without sunglasses) by the pupils and according to the colour of our eyes. In Scandinavian countries where the sunlight is less the eyes are light coloured, allowing in more light, while the converse is true closer to the equator.
The ill effects of exposure to sunlight and the danger of developing skin cancer have been widely publicised. Skin cancer usually develops as a result of inappropriate exposure to excessive sunlight, usually around mid-day in lightly pigmented individuals. Too much of anything is bad, and the same is true of the sun too.
The sun is a boundless source of energy and health. We need to expose ourselves to its slanting rays regularly in the morning or evening, to keep our moods elevated, our muscles strong, our circadian rhythms intact and our body cancer free. It helps to start the day with a suryanamaskar, our very own traditional salute to the sun.
Sources: The Telegraph (Kolkata, India)