Most of us are aware that excessive exposure to direct sunlight can cause skin cancer. Too much exposure to sunlight can also damage our eyes and even cause heat exhaustion and dehydration leading to sometimes serious consequences.
We all need sunlight because it is our primary source of vitamin D, which is important for helping us absorb calcium and therefore contributes to having stronger and healthier bones. That is why in previous generations children were encouraged to take supplements like cod liver oil during the winter when sun exposure is at its lowest levels.
These days we might be more likely to take a Vitamin D supplement because it helps us avoid direct sunlight. But even if we don't, it does not take much time in the sun to get a healthy dose of Vitamin D. Overexposure is a much more serious problem. Unprotected exposure to ultraviolet rays from the sun can cause skin damage, skin cancer, eye damage and even immune system suppression.
Children are especially susceptible to overexposure because they usually spend much more time playing outside in sunny weather. In fact, it is estimated that children get as much as 50% - 80% of their entire lifetime's worth of sun exposure before they are 18 years old. This fact makes it especially important that parents protect their children from overexposure.
Ultraviolet rays are the main culprit. Unfiltered sunlight contains three different types of UV rays: UVA, UVB, and UVC. UVA rays are the least harmful, but can still cause skin to dry out and age prematurely. They can also contribute to skin cancers such as melanoma. UVB rays are more dangerous. Many of them are filtered out by the earth's ozone layer, but more than enough get through to cause severe sunburn, cataracts of the eyes, and damage to the immune system. UVC rays are the most dangerous, but fortunately virtually all of them are filtered out by the ozone layer.
Our first line of defence against skin damage by UV rays is a chemical in the skin called melanin. The darker our skin, the more melanin it contains, and the more built-in protection the skin has against UV rays. As the skin is exposed to UV rays it "tans" -- a process which increases the skin's natural resistance to further exposure. But when the skin starts to "burn" that is a sure sign there has been too much exposure -- the melanin in the skin can only absorb so much exposure before the skin becomes damaged.
Continued damage of the skin in this way is thought to lead to skin cancer such as melanoma. In fact melanoma has been linked to frequent burning of the skin that occurs before the age of 20.
Some children are more at risk than others. Factors that increase the risk of serious skin damage in children are very fair skin and hair, the presence of moles on their skin, and a family history of skin cancer. Parents of children with any of these characteristics should take special care to protect their children against overexposure.
Other factors also make some types of exposure more dangerous than others. For instance, the more direct the sunlight, the more dangerous it is. That means that trips to regions nearer the equator will result in more intense sunlight and call for greater vigilance against sun exposure.
This also applies to the time of year. Sunlight in the summer is more intense because it is more direct -- and therefore more potentially damaging.
The best way to protect yourself and your children against overexposure to UV radiation requires you to use your common sense. First, avoid the brightest times of day when the sun's rays are most direct and most intense. If you or your children will be playing outside or engaging in some other activity for an extended period of time, try not to do these things near midday.
Second, cover up exposed skin as far as it is practical. Make sure your children's clothing provides adequate protection. You should not be able to see your hand through the material. Even on cloudy days UV rays will penetrate the cloud cover and can cause burning. This can be more dangerous because children -- as well as adults -- are not aware it is happening.
Finally, use sunscreen on exposed skin. Sunscreen should be applied about 30 minutes before going outside. Apply it generously and to all exposed skin, including the lips, ears, feet, shoulders, and back of the neck, and reapply it every two or three hours. If you or your child go into the water, reapply sunscreen after coming out.
Protective eyewear is also important. Although many children do not like wearing sunglasses at first, too much exposure to sunlight can cause damage to the cornea, and repeated damage of this sort can lead to the development of cataracts later in life. When buying sunglasses make sure the lenses have UV filters that clearly state the glasses give 100% UV protection.