Why Sunburns Are More Common At High Altitude

My friend went on a short Himalayan trek last month. As he raved about how great the trek was, I couldn’t help but be distracted by his sunburnt nose that was now peeling off. I asked him if he had used sunscreen and his answer was not very different from what most people say, “I just didn’t think of putting it on”.

Trekkers often underestimate the amount of damage the sun does to their skin. This damage is a lot more pronounced on high-altitude treks.

In this article, you will learn everything about sun damage on treks and how you can protect yourself from it.

What causes the sun to be harsher at high altitude?

UV Rays – The Main Culprit

Ultraviolet (UV) rays form one of the components of sunlight. Although they form a small component (about 5- 10%), they are the most dangerous.

UV radiation causes harm by damaging your skin cell’s DNA. This leads to sunburns, premature aging, cataract and skin cancer.

UV radiationThere are three kinds of UV radiations:

1. UVA radiation (this is what you should watch out for) – This radiation is linked to skin aging and has some role in propagating skin cancer. Though UVA radiation is of less intensity compared to UVB, it makes up for around 95% of the UV radiation that reaches us. 

2. UVB radiation – When you get sunburnt on a trek, it is because of UVB radiation. UVB rays also cause skin cancer, cataract and snow blindness. Yet, they form only about 5% of the total UV radiation that affects us. 

3. UVC radiation – This radiation is absorbed by the Earth’s atmosphere and does not reach us.

What is the difference between a suntan and a sunburn

Before we dive any deeper, we must learn the difference between a suntan and a sunburn.

Very simply, a tan is when your skin changes colour and becomes dark. You tan when your body is reacting to UV light to prevent UV damage.

A sunburn is when the skin turns red and painful and begins to peel off. You sunburn when your skin cells have already been damaged by UV radiation and your body is now trying to repair the affected areas by sending in more blood supply and getting rid of damaged skin.  

So a suntan is not a bad thing but a sunburn is.

sunburn-high-altitude
Exposing your skin to the sun can either cause suntan or sunburn, depending on the amount of melanin in your skin. Picture taken on the Gaumukh Tapovan trek by Harshith Sai Kosaraju

To get a little more science-y: You get a tan when the melanin in your skins jumps to action to protect it from UV radiation. Melanin is the pigment that gives skin its colour. So people with darker skin have a higher concentration of melanin. This allows them to be slightly more resistant to sun damage.

On the contrary, people with more melanin also tan more easily. The tan is an indication that your body’s melanin has begun to fight the UV radiation. So if your face tans quickly on a trek, it means that your body has already begun to put up its sun defence.  

Melanin is not 100% efficient at blocking UV radiation all the time and you must take measures to protect yourself. I’ll get to that in a bit.

Why the sun is harsher at high altitude

You may have gone on daily jogs while preparing for your trek. Let’s say that you jogged for an hour everyday. You tanned a bit but never got a sunburn. Yet on the trek, your skin was red and peeling within a few hours. How come?

We get sunburnt more easily at high altitudes than at sea level. This is because the sun is much harsher here.

There are three main factors that contribute to this:

1. Thinner Atmosphere: The atmosphere is our first line of defense against UV radiation. Constituents like ozone and water vapour do the job of absorbing some UV radiation. However, at higher altitudes, the atmospheric layer is thin. This allows more UV radiation to pass through. In fact, with every gain of 1000m (3280 ft), the level of UV radiation increases by approximately 12%!

sunburn-high-altitude
The atmospheric layer is thinner at high altitude, making it easier for harmful radiation to reach us and cause sunburns. Photo by Tushar Mone taken on the Kedarkantha trek in winter.

2. Snow: UV radiation reflects off surfaces easily and snow is a very reflective surface. In fact, it reflects nearly 80% of UV rays. In comparison to snow, dry land reflects only about 4% UV radiation.

sunburn-high-altitude
Snow is highly reflective and reflects up to 80% of the UV rays from the sun. So if you’re trekking in snow, be all the more wary of the sun. Picture by Sudheer Hegde taken on the Dayara Bugyal trek in winter

3. Cloud Cover: You are susceptible to UV exposure even on a cloudy day. Clouds don’t block out all UV radiation. So even when you are summiting a mountain under a cloudy sky,  and you should still wear your sunscreen.

Brahmatal-Indiahikes-AnirbanBanerjee
A cloudy sky does NOT mean there is no possibility of suntan or sunburn. We still recommend wearing sunscreen even on cloudy days. Picture by Anirban Banerjee taken on the Brahmatal trek in winter

How To Protect Yourself And Avoid Sunburns

The Earth’s atmosphere absorbs some of the UV radiation. It does a good job of absorbing all of UVC rays and most of UVB rays. But there is still a decent amount of UVA and some UVB radiation that gets through.

There are three really easy ways with which you can protect yourself from excessive UV exposure:

1. Cover Up

The most convenient way to protect yourself from sun damage is to cover exposed body parts. When you’re out trekking in the sun, pull your sleeves down to cover your arms. Remember to keep your neck and ears shaded as well. Wear a sun hat or a broad-rimmed hat that can cover these parts.

I always carry a scarf with me. In case you lose your sunhat, you can cover-up easily with it. If I’m trekking with only a peak cap, then I put the scarf under the cap so that it covers my neck and ears.

Trek Leader Devang wears a sun hat to shade his face and ears. He also keeps a scarf handy at all times to protect his neck and face areas.

2. Sunscreen

Sunscreen is an absolute must on any high-altitude trek (and daily life). Your face and hands are the most exposed parts of your body. This makes them more susceptible to sunburn.

Depending on what formula of sunscreen you buy, it protects you by either reflecting or absorbing UV rays. 

Here are some tips on how to properly use sunscreen while trekking:

1. Use sunscreen that is rated SPF 40 or more. If you can’t find SPF 40 then go for SPF 30, but not lower than that.

2. Apply sunscreen on all exposed body parts 30 minutes before setting out on the trek.

3. No matter what rating of SPF your cream has, reapply every 2 hours.

4. Apply abundantly. You need a good layer of sunscreen to do its work effectively so don’t be stingy with it.

5. Buy a ‘broad spectrum’ sunscreen. Broad spectrum sunscreens block out both UVA and UVB rays. They usually have the phrase ‘broad spectrum’ printed on their labels. Broad spectrum sunscreens are easily available in the market. If you wish to make your own organic sunscreen at home, you can learn about here.

6. Use sunscreen regardless of any predispositions that you may have. The sun does not discriminate between age, race, gender, religion etc.

3. Wear Sunglasses

UV rays damage not only your skin, but also your eyes. Short term exposure may cause snow blindness and long term exposure may lead to cataract.

Snow blindness (photokeratitis) is a condition when your eyes get sunburned. This happens because snow reflects sunlight and UV rays. If you trek in snow without eye protection, it can damage your cornea, which is what snow blindness is. It causes a gritty, burning sensation in the eyes and temporary loss of vision.

Such discomfort is easily avoided by using sunglasses. Always put on a pair of UV protection sunglasses if you are going to trek on snow for a long duration. For those who wear spectacles with eye power, there are sunglasses available that can be worn over your spectacles.

What To Do To Heal Sunburns

The only way to deal with a sunburn is to let the skin peel off and let your body regenerate the burnt skin. While your body repairs itself, you can use these methods to soothe and cool down the affected skin:

1. Cover the affected area and try to expose it as little to the sun as possible.

2. Calm the burnt area by covering it with any of the following:

  • Lacto calamine lotion
  • Aloe vera get (my favourite)
  • A mixture of curd and lemon
  • A concoction of cream (malai), multani mitti (Fuller’s earth) and cinnamon.

The effects of a sunburn can appear either immediately or a few days later. It depends from person to person. It is an uncomfortable condition and takes 4-5 days to heal. Yet it is easily avoidable. So the next time you’re climbing a mountain, remember to always wear your sunscreen.  

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Lavanya Pangtey

Lavanya Pangtey

Lavanya shares a strong bond with the mountains and coming from Uttarakhand, she has seen their face change over time. Though a law graduate, she works at Indiahikes as a Content Manager. Through this platform, she hopes to help people become more aware about sustainable trekking.

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