Being in or near water can increase your risk of sun exposure. While water provides a refreshing escape, it does not offer complete protection from the sun’s ultraviolet (UV) radiation. Several environmental and behavioral factors can lead to greater sun exposure and a higher chance of sunburn when enjoying aquatic activities. Understanding these factors helps protect your skin effectively.
Understanding UV Rays and Water
Water interacts with ultraviolet radiation in complex ways. While it can absorb some UV, especially shorter UVB wavelengths, a significant amount of UV radiation can still penetrate the surface. Approximately 40% of the sun’s UV can reach 50 centimeters deep, and UVA rays can penetrate several meters, even over 70 meters in clear ocean waters. At a depth of about a meter, UV intensity can still be around 18%.
The clarity and composition of water affect how deeply UV light penetrates. Clear water, such as in oceans or pools, allows for deeper UV penetration compared to turbid or coastal waters with more dissolved organic matter. Beyond direct penetration, the water’s surface also reflects UV rays, acting like a mirror. This reflection can significantly increase exposure for individuals on or near the water, with sea foam reflecting 25% to 30% of UV and dry beach sand reflecting 15% to 18%.
Factors Increasing Sun Exposure Near Water
Spending time in water can create a “cooling effect” that masks the sensation of the skin heating up. This can lead individuals to stay in the sun longer without realizing their UV exposure, increasing sunburn risk. The refreshing feeling of water can delay the body’s natural warning signs, such as feeling hot or noticing skin redness, which prompt seeking shade. This prolonged, unnoticed exposure allows more UV radiation to reach the skin.
Physical activity in water also contributes to reduced sun protection. Activities like swimming or surfing can cause sunscreen to wash off more quickly, even if water-resistant. Sweat, often produced during active water sports, further diminishes sunscreen effectiveness, necessitating more frequent reapplication than dry-land activities. People frequently spend extended periods outdoors near water, often during peak sun hours between 10 AM and 4 PM, escalating their exposure.
Protecting Your Skin Near Water
To minimize sun exposure and prevent sunburn near water, apply broad-spectrum, water-resistant sunscreen. Sunscreen with an SPF of 30 or higher is recommended, as it filters out about 97% of UVB rays. Apply sunscreen generously to all exposed skin 15 to 20 minutes before sun exposure, and reapply every two hours, or more frequently after swimming or sweating.
Seeking shade is another effective strategy, especially during the sun’s most intense hours, from 10 AM to 4 PM. Utilizing umbrellas or natural shade can significantly reduce direct UV exposure. Wearing protective clothing also provides a physical barrier against UV rays. Options include rash guards, wide-brimmed hats, and swimwear with a UPF rating of 50+, which blocks approximately 98% of UV radiation.