The psychological condition best known for a lack of sunlight is called Seasonal Effective Disorder (SAD).

Largely undiagnosed in the west, SAD is said to effect upwards of 20 percent of northern latitude populations in vary degrees of severity during the winter months.

The Anatomy of SAD

The symptoms of SAD may include depression, sleep disturbances, fatigue, carbohydrate cravings and weight gain. The typical SAD sufferer tends to experience these symptoms at the same time every year at the onset of winter.

Treatment for SAD usually consists of artificial light therapy and/or drugs such anti-depressants known as selective serotonin re-uptake inhibitors (SSRI's). Unfortunately artificial light boxes are often too weak to make a measurable difference and SSRI drugs can have negative side effects.

Science now believes that natural sunlight plays an integral role in mental health by regulating neurohormones responsible for mood and behavior.  Studies show that people, who get appropriate sun exposure in the summer months, tend to have less occurrences of SAD in the wintertime.

Sunbathing Safely

There is no doubt that excessive sun exposure will accelerate skin aging and increase the risk of skin cancers. The goal should always be moderate sunbathing to achieve optimal hormonal response.

There are no steadfast guidelines, as each individual has different requirements based upon skin color, age, geographic location, nutritional status and time of year.

When sunbathing it would be wise to follow a few universal principles:

1. To avoid over heating, do not sunbathe in temperatures above 64°F/18°C.Early morning sunlight before 11:00 a.m. is best.

2. Expose as much of your body as possible.

3. Wear a hat to protect your eyes and the thinner more sensitive skin on your face and neck from direct sunlight.

4. In order to obtain full spectrum sunlight, apply sunscreen after your brief sunbathing session, if you intend to stay outdoors.

5. Eat a healthy whole food diet with colourful fruits and vegetables to minimize free radical production.

6. Do not get too comfortable – you may fall asleep and risk severe sunburn.

7. Try to evenly space your sunbathing throughout the spring and summer, rather than cramming it all into a short period of time.

8. When heading south for winter vacation, increase your sun exposure gradually.

Skin colour is another variable that will determine not only how long you can sunbathe before burning, but also how much sun exposure you need to achieve optimal vitamin D levels.

People of African descent, with naturally darker skin pigmentation, require six times as much sunlight exposure than people of northern European descent who have very light skin pigmentation.

This may explain why darker skinned individuals living in northern hemispheres suffer from a disproportionate number of diseases related to vitamin D deficiency.

A safe sun exposure scale based on skin pigmentation may look like this:

• White skin- Northern European descent
• Safe exposure: 20-30 minutes
• Olive skin- Asian, Mediterranean descent
• Safe exposure: 50 minutes
• Dark brown skin- Indian, Arabic, South American descent
• Safe exposure: 70 minutes
• Black skin- African, Caribbean descent
• Safe exposure: 120 minutes

These time limits refer to afternoon sun exposure, when the sun is generally at full intensity.

It seems as though modern science is beginning to rediscover what ancient sun worshipping cultures knew to be truth – that sunlight is a powerful life giving force of nature that is fundamental to human health and evolution.