'Get comfortable with being uncomfortable’ is a bumper sticker slogan that most endurance athletes can relate to. Pain is viewed as part and parcel of sport, particularly in ultra and adventure events. 

Scientific evidence suggests that well-trained endurance athletes learn to tolerate pain for longer than non-athletes, which probably makes sense when you consider how much time we spend pushing ourselves outside our comfort zone.

The pain caused by endurance sport manifests in many ways but a review found that the most common injuries affecting ultramarathon runners are dermatological, with foot blisters and chafing coming in near the top of the list.

The easy option for many endurance athletes is to ignore the early warning signs of blisters or chafing and to push through in the hope that things will improve before reaching the finish line. The risk with this approach is that what starts as minor skin irritation can develop into something more serious and end up compromising technique and/or causing other injuries. 

Avoiding chafing in the first place and knowing how to manage it if it does occur are therefore essential skills for serious endurance athletes. 

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Why do endurance athletes chafe?

Technically speaking, chafing is a friction-induced skin injury caused by repetitive rubbing between skin and skin, or skin and clothing/equipment (e.g. wetsuit, seat or backpack). The outer layer of skin (the epidermis) is rubbed, gradually causing microscopic tears.

Underneath the epidermis is the dermis, which becomes exposed when the epidermis is breached and left red, raw and irritated. Some areas of the body are particularly vulnerable to chafing, including the thighs, groin, underarms, neck, under breast and nipples. 

Image Credit: Finlay Woods ©

Pro athlete Dougal Allan, who has twice won the 243km Coast to Coast Race in New Zealand, recalls a time when he tested the dermis on his lower back to the limit during a kayak race early in his career:

By the end of the race, I had raw flesh exposed across the top of my backside. It took weeks to heal.

I sent a photo of it to my coach who worked with Olympic kayakers and he said it was easily the worst kayak chafing he’d ever seen.

Often it’s not actually the chafing that makes our performance suffer; it’s the knock-on effects. For example, the kind of chafing Dougal described will have hampered his ability to sleep properly post-race, hindered his recovery, kept him out of full training for weeks, and could easily have led to infection. All of this highlights the potential consequences simply ‘losing a bit of skin’ can have and why it’s sensible to try to avoid it happening in the first place. 

Does sweat make chafing worse?

Sweating is a necessary and valuable cooling mechanism during exercise, although it can exacerbate issues when it comes to chafing. Sweat’s saltiness and moisture are double-trouble for the skin, hence why blisters and chafing can often be worse in hot, humid conditions. 

Firstly, moisture leaves the skin prone to damage. On top of this, when sweat evaporates, it can leave behind a gritty layer of salt crystals on the skin, increasing friction and irritation. One study demonstrated that sweat contributes to a higher coefficient of friction between skin and fabric, compared to liquids of a lower mineral content or completely dry skin. 

Of course, different individuals sweat at different rates and their sweat contains different amounts of sodium, so there's possibly some logic in the theory that those of you who are high-rate, salty sweaters are more prone to chafing.

How to avoid and treat common types of chafing

*Warning: This section contains images of blisters and chafing that some readers might find upsets their dinner plans.

Foot Blisters

Blisters develop when friction causes the epidermis to separate from the dermis. Clear fluid (either serum or plasma) fills the gap and forms a blister to protect the damaged skin and aid healing. Friction blisters are usually filled with clear, sterile fluid, but blood blisters occur when blood vessels in the skin have also been damaged, and hence the blister fills with blood.

Ultrarunner Rory Coleman recounted a painful experience early in his endurance career while running The Grand Union Canal Race:

I got to about half-way, it was raining and my feet got waterlogged. My training shoes and low-quality socks degloved my foot; all the skin on the bottom was flapping. It had just come off.

It often takes some trial and error to find what works for you when it comes to prevention.

Experimenting with shoe and sock choices early in the season, hardening or softening the skin on our feet, trying out different tapes, lubricants, powders are all common in an attempt to keep blisters at bay. During multi-stage events, it’s a good idea to air your feet and dry your clothing and equipment.

Having said that, the extreme environments, distances, terrains and constant sweating associated with endurance events means prevention isn’t always possible. A study found that 100% of athletes at The Gobi Challenge ultramarathon suffered with foot blisters.

Image Credit: Wikimedia ©

If you can feel a blister forming, the appropriate course of action will depend on the context. There’s some instances, for example in the last 10km of an ultramarathon, where gritting your teeth and pushing through the pain to keep your place is necessary. 

In other scenarios, early attention to the problem will be superior. Generally, the more time remaining in the race and the greater possibility of the issue worsening, the more advisable it is to spend a couple of minutes addressing the problem early.

Robbie Britton, one of Great Britain's top ultra-distance runners, said:

If you do have some rubbing in a race, don’t be afraid to stop and sort it straight away. 30-60 seconds applying tape might be the difference between you crushing the last few checkpoints or hobbling through like you’ve sh!£ yourself.

In everyday life, medics would encourage you to leave a blister alone; bursting it pops the nice sterile bubble in which it can heal itself. When racing, this isn’t always practical and you might feel you need to relieve the pressure of the blister.

To avoid infection, cleaning the blister, surrounding skin and your hands is advisable if possible. You can then pierce the roof of the blister with something sharp, and preferably clean, and drain the fluid by applying gentle pressure while doing your best to preserve the top layer of skin. Clean it again and then dry the area before placing a patch over the top and taping the foot. Finally, slap on a clean pair of socks and plough on. Following the race, foot hygiene and rest are crucial to let your feet heal and avoid infection.

Runner’s nipple

As the name would suggest, runner’s nipple is the issue where chafing occurs between the running top and nipple, causing irritation and even bleeding. It’s associated with long-distance running and sometimes colder conditions when nipples are more likely to be erect.

A potential way of reducing the risk of runner's nipple is to place tape over the nipples, while also consider the position of embroidery on vests or the pins on race numbers as these can cause additional unwanted friction.

Upper thigh chafing

Chafing can also cause injuries to occur due to altered technique. Robbie Britton recounted:

You don’t spend over 12 years in ultra-running without your fair share of chafing stories, but they do get further apart as you get more experienced (normally).

One of my worst was when I stitched a hole in a pair of shorts I had before a 24-hour race. The seam was on the inside, a little raised and pretty close to an important, sensitive, part of my anatomy.

The chafing started early doors, meaning my running gait was "interesting" in the second half of that race.

If you experience rubbing between skin, particularly the upper thighs, clothing choice can be very important. Tight-fitting clothing, such as compression shorts, can act as a protective barrier to avoid the friction that causes microscopic tears to the epidermis. A sweat-wicking, breathable fabric allows sweat evaporation, reduces moisture on the skin, and avoids additional friction.

Alternatively, chafing can be made worse by poor choice of clothing, potentially if it’s too loose, has irritating seams or is wet. 

Image Credit: James Phillips ©

Anti-chafing lubricants and balms can also be lifesavers to reduce friction and encourage skin areas to slide over each other smoothly. Slathering on good old Vaseline is a common choice, but if you're willing to pay a little extra, a more specialised product such as Gurney Goo goes the extra mile. Created by Steve Gurney following some race-threatening chafe experiences, Gurney Goo is an anti-chafing, anti-blister solution with the added benefit of Teatree for antiseptic qualities. The goo is designed to keep the skin dry, even in wet conditions, and is highly reviewed by many athletes.

Given that moisture is chafing’s best friend, keeping dry is important. Drying out wet clothing between stages of an event is useful. If salt has dried on your clothing from a previous stage and you don’t have spare, rinsing your clothing with water between days can be useful to avoid irritation if it has time to dry before setting off again.

In addition, other weapons in the battle to keep you and your equipment dry include antiperspirants that dry into powders, talcum powder (this can be useful in the shoes of triathletes for blister prevention and smoother transitions) and dry socks in the kit bag to change into when necessary.

Skin and equipment chafing

While sporting equipment has developed drastically over time, an issue that many athletes still encounter is chafing between their skin and equipment. 

If you’re an experienced cyclist, you will more than likely have experienced saddle sores. The danger with saddle sores is that, given the region of the body they occur in, the sweat, rubbing and damaged skin can quite easily lead to painful infections which will significantly affect your performance, training and recovery.

Pro triathlete Brad Williams learnt from mistakes in his cycling career and has provided some advice on how to avoid saddle sores:

I was tight on money and bought a very cheap pair of cycling shorts, which led to the worst saddle sores I’ve ever had. I quickly learnt to buy high quality shorts for best comfort. Applying chamois cream pre-ride and even mid-ride on longer days has been extremely useful for prevention.

Furthermore, never wear your cycling shorts twice without washing them thoroughly inbetween; otherwise bacteria will build up and, if rubbing does occur, you're asking for it to get nasty. It’s a good idea to have some antiseptic cream on hand, just in case it does all start to go wrong. Another useful tip is to avoid stubbly hair down there as this will cause additional friction that can lead to sores. 

Wetsuit chafe is another example where rubbing between skin and equipment can be a real pain in the neck. Often, this is made worse when swimming in the sea as, like sweat, the moisture and salt make the skin particularly vulnerable. 

Image Credit: Jonny Tye ©

A famous example of this was when Ross Edgley swam around Great Britain. He shared images of the back of his neck with little intact skin remaining. Ross and his team tried lubricants, cutting the wetsuit but in the end resorted to ditching the wetsuit as in his words, “you can’t get wetsuit chafe if you don’t wear a wetsuit”.

In terms of prevention, be very generous with the anti-chafe lubricant from the start and make sure any velcro at the back of the neck is tucked away. 

If chafing occurs on any part of the body, clean the skin early by showering with lukewarm water and an antibacterial soap to help avoid infection (warning: this will sting). Pat the skin dry (no rubbing!) and apply a healing ointment such as Sudocrem. You can cover the chafed area with gauze for protection but make sure the skin can breathe while healing. 

Skin and prostheses chafing

Athletes who wear prostheses are often familiar with chafing. The problem arises where the residual limb meets the socket of the prosthesis, particularly if the socket hasn’t been moulded optimally. Even with a good fit, the residual limb constantly changes size and/or volume acutely, due to blood flow, muscle activity, and as a result of training adaptation. 

With chronic changes, the prosthesis fit can be adjusted consistently, but with acute changes this isn’t possible, hence chafing can become a problem. Dr Bryce Dyer, an expert in the design and development of prosthetic limbs for athletes, said:

An amputee can suffer with an extreme situation where their stump rubs the inside of their prosthetics limb socket as its volume or shape changes. Whilst prosthetic sockets are carefully moulded and shaped to fit an athlete, this precise fit can change based on the type of exercise that they’ve been doing which may then create swelling, shape changes or abrasions.

Getting a good-fitting prosthesis is important, but what can be overlooked is testing it in a sport-specific setting. For example, if you’re going to be cycling with a prosthetic, test it on the bike at race-pace. If possible, seek a prosthetist with sport-specific knowledge to get an optimal fit. 

Prevention is better than cure

Chafing, in the many and varied forms it takes, is a common issue amongst endurance athletes. Once chafing rears its ugly head, it’s difficult to stop it from affecting your performance, future training and recovery. Therefore, prevention is usually better than cure. 

So, go into long events prepared for the worst case scenario. A small blister kit, roll of tape and tube of anti-chafe cream may save your race if a dermatological issue does arise.

The importance of post-race recovery shouldn’t be underestimated. Training prepares your body to tackle these ultra endurance challenges, but there’s a responsibility to ensure your body (including your skin) gets the break it needs, particularly if it has been damaged.

Further reading