The Sun's Physical Effect on Humans

The Good News

• First of all, the sun gives us life! It gives us light, heat, and a stable environment. It regulates the water cycle on Earth, allowing rain to fall to the ground and evaporate back into the atmosphere. Plants use the sun to help in photosynthesis. They turn water and carbon dioxide into carbohydrates and give off oxygen. This helps plants grow and provides humans with the oxygen that we need. And its all thanks to the sun!

• Besides giving life, the sun regulates our biological clocks, helping us maintain the regular schedule of sleep and wakefulness that we need to function at our best.

• Sunlight has also been shown to provide vitamin D : essencial in itself but also a vital part of calcium absorption. Exposure to moderate amounts of UVB from the sun allows the skin to store the vitamin D that it recieves and convert it to a usable form in the kidneys at a late time

• Sunlight helps the body produce nutrients needed to maintain bone mass and lessen the risk of osteoporosis.

• Some studies suggest that moderate sunlight can lower blood pressure and increase the oxygen capacity and circulation of the blood.

• It can also boost white blood cell production, a function that is needed for the immune system.

• Sunlight stimulates the pineal and pituitary glands, two light sensitive organs located behind our eyes that help regulate hormones.

The Not-So Good News

• Too much exposure to UV light can result in various types of skin cancer , of which melanoma is the most life threatening.

• Excessive sunlight can also wrinkle the skin and damage hair. This process involves the enlargement of blood vessels in the cheeks and neck and the spotting of skin on the hands. Hair becomes rough and nails may also become brittle.

• Harsh UV sunlight damages the eye , leading to photokeratitis and photoconjunctivitis. Both of these burnt the tissue of the cornea. It can also lead to abnormal white growth on the cornea itself. In some cases, the retina

• The heat of the sun over long periods of time can heat tissues in the body, leading to stroke or radiation overload

How Can You Stay Safe?

• Avoid too much direct sunlight, especially in the middle of the day when the sun is strongest

• Keep a pair of sunglasses handy when you are outside.

• Sunblock is a must! (try SPF 20 or more) Even on cloudy days, remember to use a good amount to protect yourself.

• Keep your skin covered with light clothing to avoid constant exposure to the sunlight.

• Most of all: Never look directly at the sun, even if you are wearing sunglasses! This can cause permanent damage to your eyes.