With summer in full swing, it’s important to stay hydrated and protect yourself from the heat and sun. Wearing sunglasses to protect your eyes, a hat to keep the sun off your scalp and face, and light-weight clothing can go a long way, but you will likely need to wear sunscreen as well to protect exposed skin.

The Sun and UV radiation

The ultraviolet (UV) radiation in sunlight interacts with our skin cells. Cells that produce skin colour are excited by UV radiation and thus produce more pigment and a tanned/darker appearance. However, too much exposure to UV radiation can cause sun burns and increase your risk of skin cancer.

There are two types of UV that can damage skin. UV-A penetrates deep into the skin and is associated with premature aging. UV-B affects the most superficial skin layers and is credited for causing sun burns and skin cancer.

What is SPF?

Sun Protection Factor is a measure of how long sunscreen will protect you from UVB radiation. The number that follows indicates how many times longer you will be protected compared to when you are not wearing any sunscreen. For example, say your skin burns within 10 minutes in the sun. Wearing an SPF 50 sunscreen would increase your skin protection by 50X, or for 500 minutes (roughly 8 hours).

Another factor to consider is that products with higher SPF levels, tend to be more photostable. This means that they not only offer longer protection, but better protection.

Choosing the right Sunscreen

Physical vs Chemical. Sunscreens are made with physical, chemical, or both types of ingredients. Chemical ingredients absorb the UV radiation, while physical ones reflect it away from your skin. Physical sunscreens (contain titanium dioxide or zinc oxide) are sometimes preferred by those with sensitive skin but it comes down to personal preference.

Broad Spectrum. These sunscreens contain ingredients that protect against UVA and UVB radiation. All physical sunscreens are inherently UVA and UVB blocking. Here are some examples of chemical ingredients to look for: ecamsule, avobenzone, oxybenzone, and sulisobenzone.

SPF. The Canadian Cancer Society recommends using sunscreen with at least SPF 30.

Environmental Impact. Certain sunscreen ingredients may have a negative impact on the environment. For example, oxybenzone has been linked to coral bleaching.

Applying Sunscreen

Apply sunscreen at least 20 minutes before sun exposure and reapply regularly if swimming or sweating. Apply liberally and ask a friend to help you protect those hard to reach areas. Remember to use an SPF lip balm and to apply sunscreen to ears, as these areas are often missed.

For more information, visit the CCOHS Skin Cancer and Sunlight page.