Time spent outdoors training and racing is one of the many upsides of taking up triathlon. But all those long hours spent swimming, cycling and running – often during the hours where UV radiation is at its highest – come with a risk. And a 2023 literature review on skin cancer risk and sun protection knowledge in athletes published by the National Library of Medicine showed that “despite the risks, outdoor sports participants seem to not protect themselves from the sun adequately…. Although knowledge about the risk of malignant skin lesions was satisfactory, the sunburn rates were very high.”
We take a look at the risks to be aware of when you’re training outdoors, including the impact of being in water, training at altitude and sweating. And share some tips on how to mitigate the risks of sun-related skin damage. So you can train hard and race strong – but stay safe and avoid long term harm.
Are endurance athletes at a higher risk of sun-related skin damage?
Those regularly participating in outdoor activities are, naturally, getting more sun exposure. Which is great for topping up those all-important vitamin D levels. But in turn can lead to a higher risk of developing skin cancer as a result of UV damage. Research notes that along with higher levels of UV exposure, “activity-induced immunosuppression and increased skin photosensitivity due to sweating also work against athletes.” And while it’s been found that knowledge of the risks of UV exposure is generally pretty good, the use of sunscreen and other protective measures is often inadequate – with high prevalence of sun burn.
A study* investigating sunburn among cyclists found an average sunburn rate of 45.6% – with those under 40 years old being the most likely to have experienced a sunburn. And among runners, of the almost 2500 runners surveyed – only 23.5% were practicing adequate sun exposure and protection behaviours.
“The most popular photoprotection technique among runners was wearing sunglasses. Regarding sunscreen cream, 49% claimed that they forgot to apply it, and 17.3% felt uncomfortable wearing it.”
And while most of us know that we need to be regularly applying sunscreen during training, and on race day, there are certain additional risks that we might not be aware of.
*Skin Cancer Risk, Sun-Protection Knowledge and Behavior in Athletes—A Narrative Review, Kliniec et al 2023
Sun exposure risks while swimming
Whether you’re heading to your local outdoor pool, or hitting the open water. It’s just as important to think about sun protection while swimming as it is on a long training ride.
Information from the European Code Against Cancer notes that water reflects 5-10% of the UV from the sun, creating additional reflected exposure alongside direct exposure. And a literature review study highlights that “individuals participating in water sports are exposed not only to UV radiation, but also to the washing off of sunscreens.”
It can be easy to forget about the risk of sunburn while swimming. Particularly as the cooling effect of the water reduces your awareness of the sun’s heat on your skin. Where you might ‘feel’ like you’re getting sunburnt on dry land, and remember to reapply the sunscreen. When you’re in the water, it’s far easier to forget until it’s too late. And even if you’re swimming in a wetsuit with most of your skin covered, areas such as your face and wrists are still getting exposed to UV.
Does sweating increase the risk of getting sunburnt?
It might seem fairly obvious that sweating during your training is going to reduce the effectiveness of your sunscreen, which is why it’s so essential to use a sunscreen which is sweat-resistant as well as water-resistant. But it’s also important to note that sweating may also increase the photosensitivity of your skin, which could further increase the risk of sunburn.
A review of the literature* around knowledge and behaviour related to sun exposure in sportspeople states: “It is important to also mention that sports that involve increased perspiration require more photoprotective measures as sweat can influence the hydration of the corneal layer of the skin, causing less reflection and dispersion of UV light and increasing the risk of sunburn.” Therefore, forgetting to reapply your sunscreen during a long training day – or not applying it in the first place – can carry an increased risk of skin damage.
*Knowledge, Behaviour and Attitudes Related to Sun Exposure in Sportspeople: A Systematic Review, Fernandez-Ruiz et al 2022
Is UV more intense at altitude?
Endurance athletes will often head up to altitude to train, with the benefits including increased red blood cell production and a boost to aerobic capacity as a result of training in an environment with lower atmospheric pressure.
However, it can be easy to get caught out on the sunburn front when you head for the hills. That’s because as the atmosphere gets thinner, less UV radiation is filtered out. According to The Skin Cancer Foundation “UV radiation exposure increases 4 to 5 percent with every 1,000 feet above sea level.” Plenty of popular triathlon events take place over 2000ft above sea level. So whether you’re heading off on an altitude training camp, or taking on a mountainous race. It’s important to account for the increase in UV intensity.
The clouds haven’t got you covered when it comes to sunburn risk
When the sun is blazing, we’re far more likely to reach for the sunscreen and take other protective measures. But without the visual cue of the big yellow thing in the sky, we can all make the mistake of assuming we don’t need to worry about getting sunburned when it’s cloudy out. In reality, while the clouds do block some UV, “over 90% of UV rays can still pass through cloud and cause sunburn.” (Cancer Research UK). Which is why it’s important to check the UV index, and still take protective measures, even if it’s cloudy.
Triathlon GOAT Mark Allen highlights the risk of sun exposure for endurance athletes
In 2022, triathlon legend Mark Allen posted a video detailing his own brush with skin cancer as a result of sun exposure. Best known for ‘The Iron War’ shoulder-to-shoulder run battle he had with Dave Scott at the IRONMAN World Championship, Allen shares his experience of MOHs surgery to remove cancerous cells after his own skin cancer diagnosis. And shared a crucial reminder to endurance athletes to take care of their skin.
“If you’re an endurance athlete, you’re probably in the sun a lot, if you like being outdoors you’re in the sun a lot. Its not something that can be fixed today if you had bad habits in the past… I wish I had listened to my own advice 20 or 30 years ago and used a lot more sunscreen.”
How to avoid sunburn and skin damage during training and racing
So that’s the risks covered. But when you’re training for an event, or participating in an all day race such as a long distance triathlon. Simply staying out of the sun isn’t always an option. So what are the things you can do to reduce your risk of sun-related skin damage?
1) Use a sports-specific sunscreen
Given what some of the literature reviews have shown about the lack of sunscreen use in endurance athletes, we all need to remember to use sunscreen in the first place. But to ensure your sun protection is as effective, and comfortable, as possible. It’s also important to opt for a sports-specific sunscreen designed specifically to cope with the demands of long training sessions.
Unlike a regular sunscreen, which will wash off pretty quickly if you’re swimming or sweating heavily. A sports-specific sunscreen is water-resistant and sweat-resistant. They often have 6-8 hour wear, so you’re protected for longer. Though it’s always worth reapplying after swimming, to be on the safe side. Look for sports sunscreens which also offer breathability. This will help to reduce the sticky, clammy feeling you might have experienced when trying to exercise wearing a regular sunscreen.
Are you getting enough?
It turns out that those of us who do remember to apply sunscreen, have a habit of not actually applying enough of it to get the sun protection stated on the bottle. Research on sunscreen application found that people tend to apply less than 50% of the amount of sunscreen required to get the stated level of protection.
“Be sure to wear the directed amount of sun protection (always more than you think, this should be around 30ml per application for an adult). Think of it like a gel that claims to give you 40g carbs… that’s only the case if you eat the whole thing.” Pelotan sports sunscreen
More is more when it comes to applying your sunscreen. Resist the temptation to ration your supply and apply liberally to ensure you’re fully protected!
You missed a bit…
Along with not applying enough sunscreen, the other mistake plenty of us make is missing some of the less obvious bits when we’re slathering up. While you’ll probably focus on your arms, legs and face. Don’t forget the not-so-obvious areas such as the backs of your hands and wrists (especially if you’re riding a TT bike!), the back of your neck and the tips of your ears.
2) Train early or late in the day to avoid the peak UV radiation hours
Plan your training schedule to complete the majority of your sessions during hours when UV levels aren’t quite so high – UV levels tend to peak between 11am and 3pm when the sun is highest in the sky. If you’ve got a hot race coming up and you’re looking to deliberately train in the heat to get heat adaptations, you might want to consider doing at least some of these heat prep sessions indoors to reduce your overall UV exposure.
3) Consider your kit choices
Alongside applying sunscreen (and enough of it, in all the right places) you can also mitigate your risk of sun-related skin damage by considering what gear you wear. Simple things like opting for a t-shirt rather than a singlet and wearing a cap can help to reduce the likelihood of getting a sun burn. Look out for kit that has UPF protection woven into the fabrics, and gear that has quick-wicking, breathable properties to help manage your temperature.
4) Avoiding sun burn during a triathlon – race day tips
For plenty of us, we can end up coming home from a race with an unwanted souvenir of sunburn as well as a finisher shirt. Particularly in long distance triathlons, where you have no choice but to be out on the bike and the run during the heat of the day. But there are steps you can take to reduce your risk. Applying a sports sunscreen liberally before you start the race is a no-brainer. But it’s also worth having a spare bottle in your transition bag so you can quickly reapply later in the race. A roll-on or spray is a great option, so you won’t lose too much time in transition.
Wearing a sleeved tri suit rather than sleeveless can also help to reduce your risk of sunburn – particularly if you choose a suit with UPF fabric. Wearing a cap for the run is also a good idea as it’ll help to keep the sun off your face and head. You can also dunk it in water at the aid stations to help keep yourself cool.
Finally, be mindful of getting out of the sun once you’ve finished your race. It’s easy to get swept up in the post-race celebrations and not realise you’ve added a few extra hours of sun exposure. Soak up the post-race party from the comfort of the shade.
Quick-fire recap
Apply a sports-specific water-resistant and sweat-resistant sunscreen liberally prior to starting your race, and reapply in transition. Wear a sleeved tri suit to avoid getting sun burn on your shoulders and back. And wear a cap during the run to protect your head and face.
Yes, even 1 metre under water around 50% of UVB rays can still reach your skin! Water also reflects 5-10% of UV from the sun. Ensure you use a waterproof sunscreen and reapply regularly when swimming outdoors.
The atmosphere is thinner at altitude, therefore less UV radiation is filtered out. Research has shown that UV radiation exposure increases 4 to 5 percent with every 1,000 feet above sea level. Therefore it may be easier to get sunburn while at altitude.
Sweat can lead to sunscreen washing off faster. Sweating has also been shown to change the hydration levels in the top layer of the skin, increasing photosensitivity and therefore potentially increasing the risk of sunburn.
It is recommended to apply approximately 30ml (6-8 teaspoons) of sunscreen to ensure an adequate layer of protection. More is more!
Yes. Even when there is cloud cover, 90% of the sun’s UV rays can still get through. Therefore it’s important to check the UV index (usually stated on most weather forecast apps) and wear sunscreen, even if it is a cloudy day.
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