Although applying sunscreen is now one of the basic habits of most holidaymakers, protective sprays may be less effective than the big brands would have you believe. In fact, many consumer associations, researchers and dermatologists have taken on the topic, looking in particular at waterproof sunscreen.
Waterproof sunscreen in the spotlight
At the end of May 2018, one of the largest consumer associations in the United Kingdom published a report on waterproof sunscreen. It called into question the reliability of waterproof sprays. In chlorinated water (like in a swimming pool), one product that was tested lost 60% of its efficacy. Scientific studies have also identified significant performance gaps, depending on the nature of the water tested (chlorinated or salt water).
Waterproof sprays may be fairly effective in the water, but not on the sand, and not after having wiped yourself off with a towel. It is therefore essential to reapply your sunscreen regularly, particularly after having spent a while in the water or playing on the sand.
However, although sunscreen is strongly advised in order to protect the skin, sun creams have been the target of much criticism in terms of their impact on the environment. In fact, it appears that a large proportion of their ingredients spread into bathing waters, sometimes with measurable effects on the coastal flora and fauna.
Applying sunscreen generously can prevent skin cancer
Remember that no sunscreen protects you 100% from UVA and UVB rays. The sun protection factor numbers indicated on the labels (from SPF 2 to SPF 50+) relate to the level of protection from UVB rays, responsible for sun burn. It is also very important to check that your cream protects against UVA rays, which are responsible for sun allergies and skin cancer.
Be generous when applying your sunscreen. The efficacy of these products is evaluated based on high quantities (2 mg per cm² of skin, which equates to six teaspoons of cream for the average adult human body). However, recent French studies have shown that holidaymakers generally use two times less than this recommended amount.
Finally, remember to cream up every two hours, and avoid sun exposure during the hottest hours of the day, between 11 am and 4 pm. Stay in the shade with your head covered, and wear a shorts and t-shirt to cover as much as you can of your skin.