S.A.D. Light Therapy did not exist until the 20th century. Up until then, most of the world’s population rose with the sun and went to bed when it set. Artificial light existed – but it was inconsistent, weak, expensive, often smelly – and its flickering was hard on the eyes. So, for the most part, except for a small segment of high society, humans followed the rhythms of light and seasons, just as animals and birds do in nature.

Nowadays, we manipulate our waking hours just as we do everything else in modern life, thanks to technology. Electric lighting makes short work of darkness, we set back our clocks to “save daylight”, and alarm clocks jolt us painfully awake, even though it’s still pitch dark outside.

However, you can’t fool your body. It’s governed not by our visual perception of light, but by melatonin, a hormone produced by the pineal gland within our brains, responsive only to natural daylight. As daylight diminishes, more melatonin is released. We become drowsy and desirous of more rest and less activity.

But melatonin does much more than that: It controls other glandular functions in the body, including the thyroid gland. This “butterfly-shaped” gland at the base of the throat controls metabolism and energy. Meanwhile, having done its work to slow down the thyroid gland, your winter flood of melatonin is racing off to tackle your adrenal glands.

We think we have “beaten” the seasons, and the problem of too little daylight – but some people are less fortunate than others. They are particularly affected by the lack of natural light, and by being forced to adapt to an artificial rhythm.

And it’s all caused by their tiny pineal glands.

Why do some people suffer from Seasonal Affective Disorder (S.A.D.) during winter months – and others not?

We’ve come to realize that even with our abundance of electric lighting, artificial light is inadequate in convincing the body it’s enjoying summer light. Electric lights used in the average home do not exceed 500 lux. To put that in perspective, the stormiest summer day easily produces a steady bombardment 20 times that amount.

Once doctors and scientists realized the role that natural light plays on the pineal gland and the body’s production of melatonin, “Light Therapy” was the result. There was hope for S.A.D. sufferers at last.

This involves subjecting sufferers of S.A.D. to 5,000-10,000 lux light sources – a “lux” is a unit of measurement for light – thus suppressing the production of melatonin, which in turn does not trigger all the body’s other gland to slow down for the winter. The eyes of the patient must be exposed to this light source – in other word, he can’t have his back to it, or wear heavy, dark glasses.

This light triggers the pineal gland through the eyes. Full-spectrum, or “bright white” light is specifically indicated for periods of 3-4 hours per day, from October to April. (And it goes without saying, the person receiving light therapy should never stare directly at the lights!)

This brings us to one huge disadvantage: Anyone with photosensitivity, cataracts, glaucoma, retinal disorders or other eye problems should not (if you’ll pardon the pun) expose themselves to aggressive light therapy.

It’s not practical for most people to dedicate an entire morning or afternoon to light therapy; however, if one uses the correct light source, making it’s power at least 10,000 lux, recovery from S.A.D. increases dramatically. Often, this light therapy is all that is needed, to cure S.A.D. depression.

Light boxes usually cost anywhere from $200-300 – but many enterprising people have managed to make effective home units.

And besides, says Tim P.: “Making one gives me a winter hobby!”