Deep Dive: Swimmer’s Skin

Cancer Research UK reports that melanoma skin cancer is the fifth most common cancer in the UK, accounting for five percent of all new cancer cases. Outdoor swimmers are at high risk for melanoma, sunburn and skin issues so we speak to GP in Community Dermatology, Dr Rebecca Alsop to learn more.

Why are outdoor swimmers at high risk for melanoma, sunburn, and skin issues?

There are a number of factors but these are the biggest issues:

• UV reflection: Water reflects up to 80% of UV rays, intensifying exposure.
• Long exposure: Swimmers often spend extended periods outside without shade.
• Wet skin amplifies sunburn and can magnify UV penetration.
• Barrier disruption: Salt, chlorine, and cold can strip natural oils, weakening your skin’s barrier.

Is there any truth to the claim that sunscreen is useless or harmful?

There is no scientific evidence that supports the idea that sunscreen is ‘useless’. You may see advice on social media about just using olive oil, but while it’s moisturising, olive oil offers no UV protection (SPF 8 at best), making it dangerous as a sunscreen alternative. Some people react to certain chemical sunscreen ingredients (e.g., oxybenzone), but this doesn’t mean all sunscreen is harmful – just choose the right type for your skin.

What is the difference between UVA and UVB?

The sun emits two types of ultraviolet rays that are damaging to the skin: Ultraviolet A Radiation (UVA) and Ultraviolet B Radiation (UVB). Both cause different types of damage, and not all sun creams protect against them in the same way. UVA rays are always present during daylight hours, and while you might not immediately see their effects, they’re very powerful. UVA rays penetrate the skin more deeply than UVB to cause long-term damage (including all types of skin cancer) and play a major part in the ageing process. UVB rays are the rays that are mostly responsible for sunburn and skin reddening. They don’t penetrate as deeply as UVA rays, but they’re just as damaging. They play a large part in the development of skin cancers including melanoma.

What type of sunscreen is best for frequent swimmers, especially in open water?

• Water-resistant SPF 50+ Tried & tested
• Broad spectrum (UVA + UVB)
• Reef-safe formulas are better for both skin and environment
• Stick or lotion formats last longer than sprays in water • Look for sport-specific or “wet skin” compatible sunscreens

What does SPF mean?

SPF means Sun Protection Factor and indicates the level of protection a sun cream provides against burning rays. It refers to how well the product reduces the burning effect of the sun on your skin. For example, if you usually begin to burn after ten minutes in the sun, applying an SPF 15 sunscreen will protect you for 15 times longer than that, meaning you are protected for up to 150 minutes. SPFs range from 2 to 50+, with 50+ offering the most protection against UVB.

How often should I reapply sunscreen when swimming?

Every 40-80 mins, depending on the water resistance rating of the sunscreen and after towel drying, sweating, or swimming.

Are mineral sunscreens good enough?

Yes! They are the preferred choice of sunscreen for people with skin of colour. They are great for swimmers as they:

• Contain zinc oxide or titanium dioxide
• Are less irritating for sensitive skin
• Start working immediately
• Are reef and water life friendly and more stable under sunlight.

One downside is that they can leave a white cast, though many modern formulations minimise this with a tint.

What ingredients should I avoid?

• Oxybenzone, octinoxate (hormone disrupting and reef-damaging)
• Fragrance, alcohol, parabens (irritating for sensitive skin)
• Coconut oil or heavy oils (can clog pores, especially with sweat/sunscreen buildup)

Best post-swim skincare routine to prevent dryness or irritation?

• Rinse off with fresh water ASAP
• Use a gentle, non-stripping shower gel or cleanser (non-foaming, SLS-free etc)
• Apply a hydrating moisturiser with ceramides or hyaluronic acid (I rate Garnier 7 Day Intensive)
• Use barrier-repair cream for any areas more prone to irritation (e.g. Seams of swimsuit/ wetsuit/ friction areas)

What are signs of sun damage to look for?

• Persistent dry or rough patches
• Pigmentation changes (freckles, dark spots) • Wrinkles, leathery texture (it is estimated that up to 70% of the visible signs of skin ageing can be attributed to sun damage)
• Redness or peeling

Harmless mole vs. something serious?

Look for the ABCDEs of melanoma:

• Asymmetry
• Border irregularity
• Colour variation
• Diameter >6mm
• Evolving (change in shape, size, color, or feeling)

What does early skin cancer look like?

• Flat, scaly red patches
• Sores that don’t heal
• Waxy, pearly bumps
• New growths or moles that change over time

How can I check my skin?

There are apps that can then be used to monitor your skin (MapMyMole, SkinVision, MiiSkin). Even without an app, I would suggest self-exam every three months. See your GP if anything looks suspicious. Do an initial skin check using a mirror and good lighting looking at all areas including:

• Scalp (use a comb or ask for help)
• Back, shoulders, behind knees
• Feet and toenails
• Under arms and breasts

Take photographs of any areas you want to keep an eye on. Have something visible (e.g. 5p or part of measuring tape) for scale.

Are there areas swimmers should monitor?

Yes, shoulders, back, neck, chest, tops of feet, and scalp. These areas get more sustained sun exposure and are often forgotten when applying sunscreen.

Should I moisturise before swimming?

A light, occlusive moisturiser (like Aquaphor or Vaseline) can protect against chlorine/salt, but skip anything that might interfere with your sunscreen or damage swimwear.

Read our guide to the best sunscreens for outdoor swimmers.