The Highs and Lows of Sun Exposure: Understanding the Impact of Altitude
By: Greg Seitz, MD, FAAD
As we venture into the great outdoors, whether it’s for a hike in the mountains or a day at the beach, we often consider how much sun exposure we’ll encounter. What many don’t realize is that altitude plays a significant role in how much sun we’re actually soaking up. Let’s dive into the fascinating relationship between altitude and sun exposure.
Altitude and UV Radiation
Altitude is the measurement of height above a given level, typically sea level. As we ascend to higher altitudes, the atmosphere becomes thinner, and the concentration of ultraviolet (UV) radiation increases. UV radiation is a form of electromagnetic radiation emitted by the sun, and it’s divided into three categories: UVA, UVB, and UVC.
At sea level, the atmosphere is denser, and more UV radiation is absorbed and scattered before reaching the Earth’s surface. In contrast, at higher altitudes, such as mountainous regions, there is less atmosphere to filter UV radiation, resulting in higher UV intensity and increased exposure. This heightened UV intensity at altitude means that individuals are at greater risk of sunburn and skin damage, even during shorter periods of sun exposure.
The relationship between altitude and UV radiation follows a logarithmic correlation. This means that as altitude increases, the concentration of UV radiation does not increase linearly, but rather exponentially. In simpler terms, each incremental increase in altitude leads to a disproportionately larger increase in UV radiation exposure. Therefore, even small changes in altitude can result in significant differences in UV intensity and exposure levels.
Health Impacts of UV Radiation at Elevation
Increased risk of sunburn: With higher levels of UV radiation at altitude, the risk of sunburn also rises. Sunburn occurs when the skin is exposed to excessive UV radiation, leading to redness, pain, and potential long-term damage such as premature aging and skin cancer. The risk of sunburn at higher altitudes is amplified due to the higher UV intensity and decreased atmospheric protection. Sunburn can occur more quickly and severely at higher altitudes compared to at sea level. Additionally, the risk of sunburn may be exacerbated by factors such as altitude-related dehydration and increased outdoor activities commonly associated with mountainous regions.
Heightened risk of eye damage: UV radiation can also harm the eyes, increasing the risk of conditions such as cataracts, macular degeneration, and even melanoma. Sunglasses with UV protection are essential at higher altitudes to shield the eyes from harmful rays. Without adequate eye protection, prolonged exposure to UV radiation at altitude can lead to eye discomfort, vision problems, and long-term damage.
Intensified skin aging: Prolonged exposure to UV radiation accelerates the aging process of the skin, leading to wrinkles, age spots, and sagging skin. At higher altitudes, where UV radiation is more intense, the effects of photoaging may be more pronounced. The combination of increased UV intensity and reduced atmospheric protection can result in faster skin aging and a higher risk of developing visible signs of aging prematurely.
Importance of Sun Protection
Given the heightened risk of sunburn, skin damage, and eye conditions at higher altitudes, practicing effective sun protection measures is paramount. Here are some Wyoming dermatologist-approved tips for sun protection.
Sunscreen: Choose a broad-spectrum sunscreen with SPF 30 or higher and apply it generously to all exposed skin at least 15 minutes before sun exposure. In general, sunscreen reapplication is recommended at least every 2 hours. However, at higher altitudes, reapplication should be more frequent, as the increased UV intensity can reduce the effectiveness of sunscreen over time. Reapply immediately to dry skin after swimming or sweating to maintain adequate protection.
Protective clothing: Wear lightweight, long-sleeved shirts, pants, and wide-brimmed hats to shield your skin from UV rays. Darker colors and tightly woven fabrics provide better protection than lighter colors and looser weaves. Clothing that has been specifically tested for its sun protective capabilities is labeled with a “UPF” rating.
Seek shade: Limit direct sun exposure during peak UV hours, typically between 10am and 4pm. Seek shade under trees, umbrellas, or canopies to reduce UV exposure and lower the risk of sunburn and heat-related illnesses.
Be mindful of reflective surfaces: Reflective surfaces such as snow, water, sand, and concrete can increase UV radiation exposure by reflecting the sun’s rays onto your skin. Take extra precautions when near these surfaces and adjust your sun protection measures accordingly. For example, don’t forget to protect the area under the chin as well as under the nose.
Sunglasses: Opt for sunglasses that block 100% of UVA and UVB rays to protect your eyes from harmful UV radiation. Look for sunglasses labeled as UV 400 or those that have a label stating they offer 100% UV protection.
Hydration: Stay hydrated by drinking plenty of water throughout the day, especially in high-altitude environments where dehydration can occur more rapidly. Proper hydration helps maintain skin moisture and supports overall health.
In conclusion, altitude significantly influences sun exposure, with higher altitudes resulting in increased UV radiation levels. Understanding the differences between sun exposure at high altitude and sea level is crucial for practicing effective sun protection and minimizing the risk of sunburn, skin damage, and eye conditions. Whether you’re exploring mountain peaks or relaxing by the shore, being mindful of altitude’s impact on sun exposure is essential for enjoying the outdoors safely.