Do you regularly use sun protection?
Effects of sun on the skin
Comprising roughly 16% of body mass, the skin is the largest organ of the body. Exposure to ultraviolet (UV) radiation is a major risk factor for most skin cancers. Sunlight is the main source of UV rays. Tanning lamps and beds are also sources of UV rays. People who get a lot of UV exposure from these sources are at greater risk for skin cancer.
Even though UV rays make up only a very small portion of the sun’s rays, they are the main cause of the sun’s damaging effects on the skin. UV rays damage the DNA of skin cells. Skin cancers start when this damage affects the DNA of genes that control skin cell growth.
There are 3 main types of UV rays:
- UVA rays age skin cells and can damage their DNA. These rays are linked to long-term skin damage such as wrinkles, but they are also thought to play a role in some skin cancers. Most tanning beds give off large amounts of UVA, which has been found to increase skin cancer risk.
- UVB rays have slightly more energy than UVA rays. They can damage skin cells’ DNA directly, and are the main rays that cause sunburns. They are also thought to cause most skin cancers.
- UVC rays have more energy than the other types of UV rays, but they don’t get through our atmosphere and are not in sunlight. They are not normally a cause of skin cancer.
Repeated overexposure to UV rays can lead to various forms of skin damage including:
- Fine lines
- Age spots, freckles, and other discolorations
- Scaly red patches, called actinic keratosis, thought to be the beginnings of skin cancer
- Tough, leathery skin that feels and looks dry and rough
The strength of the UV rays reaching the ground depends on a number of factors, such as:
- Time of day: UV rays are strongest between 10 am and 4 pm.
- Season of the year: UV rays are stronger during spring and summer months. This is less of a factor near the equator.
- Distance from the equator (latitude): UV exposure goes down as you get further from the equator.
- Altitude: More UV rays reach the ground at higher elevations.
- Cloud cover: The effect of clouds can vary. Sometimes cloud cover blocks some UV from the sun and lowers UV exposure, while some types of clouds can reflect UV and can increase UV exposure. What is important to know is that UV rays can get through, even on a cloudy day.
- Reflection off surfaces: UV rays can bounce off surfaces like water, sand, snow, pavement, or grass, leading to an increase in UV exposure.
You can help protect your skin from wrinkles and other sun damage with the following steps:
- Use sunscreen. Every day, generously apply sunscreen with a sun protection factor (SPF) of at least 15, choosing products that provide what’s called “broad spectrum” protection against both UVA and UVB rays. When you’re in the sun for prolonged periods of time, reapply sunscreen every two hours.
- Wear protective clothing. Whenever possible, wear long-sleeved shirts, long pants, a wide-brimmed hat, and sunglasses to further shield your skin from the sun. Consider clothes made from fabrics with built-in SPF.
- Avoid peak sun hours. Stay in the shade during the hottest part of the day, usually from 10 a.m. to 4 p.m., when the sun’s rays are at their most intense.