Sunscreen protects your skin against skin cancer and premature aging. However, it is not as effective unless it's applied correctly.
Follow these tips when applying sunscreen:
When To Apply Sunscreen:
Chemical sunscreens should be applied approximately 30 minutes before sun exposure to ensure that the ingredients have time to be fully absorbed by the skin and are then less likely to wash off when you perspire. Physical sunscreens are immediately effective after application.
Remember to reapply sunscreen after swimming or strenuous exercise/sweating.
Sunscreen should be reapplied every 2 hours to be as protective as possible, especially for those who work outdoors. Don’t forget your feet, ears and nose which are often forgotten. Also wear a broad-brimmed hat, sun glasses and protective clothing and avoid being in direct sunlight during the hours either side of midday.
How To Apply Sunscreen:
Shake well before use to mix particles that might be clumped up in the container. If using a spray-on type of sunscreen ensure you can see an even sheen on the skin, as if applied while outdoors/windy conditions you may miss some areas of the skin.
Be sure to apply enough sunscreen. As a rule of thumb, use an ounce (a handful) to cover your entire body which is the equivalent of 2gm/cm2 or a “shot glass” of sunscreen/2 tablespoons worth.
Use on all parts of your skin exposed to the sun, including the ears, back, shoulders, and the back of the knees and legs. Apply thickly and thoroughly.
Be careful when applying sunscreen around the eyes as this may irritate the eyes.
After exposure to water, or towel drying sunscreen should be reapplied and also every 2 hours while outdoors.
For example a sunscreen with an SPF of 50 is more protective than an SPF of 15 once it is applied in adequate amounts and also frequently . There is no evidence that SPF ratings above 50 provide any additional protection.
Broad spectrum coverage:
When found on a label, “broad spectrum coverage” means that sunscreen protects against both UVA and UVB, which are two kinds of ultraviolet light from the sun that can burn the skin and lead to skin cancer and premature ageing.
Sunscreens can no longer say “waterproof” or “sweatproof” because they are neither. Instead, they will say water resistant and must say how long they will remain water- and sweat-resistant.