The sun and skin health
Updated: Jun 25, 2020
As summer approaches and we emerge from lockdown, many of you will relish the chance to soak up the sun and get a good tan. However, without due care, this could be damaging. When soaking up the sun’s rays it is important to consider their effect on your skin health and explore the best ways of protecting yourself.
Why is the sun dangerous?
The sun emits two main types of rays: ultraviolet A (UVA) and ultraviolet B (UVB).
UVA has a longer wavelength and penetrates deep into the skin. It causes premature skin ageing that leads to fine lines, wrinkles, and age spots. There is no escaping UVA: it is everywhere and it also maintains the same level throughout the day. UVA rays can therefore reach your skin even when it’s cloudy, and permeate through windows to enter your cells while you are indoors.
UVB, on the hand, has a shorter wavelength and affects the outermost layer of your skin. This is why it is often felt as heat. UVB causes tanning by stimulating the melanin in the skin surface. Over-exposure to UVB causes burning and blistering. UVB varies in intensity depending on the time of day, season, altitude and length of exposure to the sun.
UVB is also associated with sun protection factor (SPF). It refers to the time UVB rays will take to redden the skin compared to if you did not use sunscreen. So SPF 30 means it will take 30 minutes longer to burn the skin relative to using no protection.
Simple ways to prevent skin cancer
Both UVA and UVB can cause skin cancer. Squamous cell cancer (scc) and basal cell carcinoma (bcc) are known to be caused through recurrent exposure to the sun’s harmful UV rays as the effects are cumulative. The powerful UV rays cause damage to DNA and this will eventually cause a mutation leading to scc or bcc. Repeated skin burning from sun exposure has a proven link to melanoma, the most dangerous skin cancer.
The best way to prevent damage from the sun is to stay covered up (especially at peak times when the sun is the strongest between 11am-3pm), wear a wide-brimmed hat and wear shades. It is also important to use sunscreen, even on a cloudy day to protect against UVA rays.
Types of sunscreen
There are two types of sunscreen: chemical and physical.
Chemical sunscreens use ingredients like avobenzone and octisalate. They absorb the UV rays before they cause damage to your skin.
Physical sunscreen use minerals like titanium dioxide and zinc oxide. These reflect the sun’s harmful rays preventing them penetrating your skin.
Which sunscreen to use
It is important to choose a broad-spectrum sunscreen that protects against both UVA and UVB. Traditional sunscreens historically protected against UVB, but now most manufacturers are aware about the harmful UVA rays and have adapted their products accordingly. However, it is always best to check the label. There is some evidence to show that certain chemicals in sunscreen get absorbed into the body when used in large quantities on a regular basis. Using a physical sunscreen that does not penetrate the skin may therefore be a safer option while providing all the protection required. Finally, choose a sunscreen with at least SPF30 and remember to re-apply every few hours.