September 11, 2018

Blisters, Chafing and Black Toenails. The Ugly Side Of Running

Blisters, chafing and black toenails are not only ugly, they’re painful and can prevent you from performing at your best. Here’s how to prevent and treat them.

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There’s an ugly side to running.

No, I am not talking about the guy who shits himself in the later stages of the marathon, the girl with the nasty tanlines or the person crawling across the finish line (although, those are all pretty ugly).

I’m talking about the superficial (and often painful) eyesores that almost all runners face at one point or another.

The blisters, chafing and black toenails.

While I’ve had my fair share of blisters and chafing, I am happy to say that I’ve never had to deal with any black toenails (knock on wood).

To help ease the suffering, I reached out to Tim Maiden to help me with this post.

Tim is the lead podiatrist at The Foot Practice here in Singapore.

With one of the grossest jobs around, he spends a good chunk of his day helping athletes to solve these problems so that they can minimise the pain and disruption to their training schedule.

Here’s what Tim has to say.

Podiatrist, Tim Maiden


Blisters are one of the most common causes of soft tissue injury in runners. They’re the accumulation of micro-tears under the skin surface (between the layers of the skin) which form a fluid-filled bubble.

What Causes Blisters?

Blisters are caused by the skin exceeding its tissue stress capability. When the skin is stretched too far for too long, it stops gliding, which can increase specific pointed pressure or increase stickiness (shear).

Biomechanics is sometimes a factor in blister formation too, which explains why some of you will get blisters in certain places such as your small toes or on the Achilles tendon, which is often linked with tight calf muscles.

What can you do to prevent blisters?
The good news is that blisters are 100% preventable. My favourite blister prevention techniques are:

  1. Shoe lacing techniques.
  2. Engo plasters.
  3. Toe socks.
  4. Orthoses.

As with all conditions you need to understand the cause to treat effectively or prevent.

I think the most common misconception is the use of lubrication to stop a blister. Lubricating a blister will often lead to increased moisture in the skin which increases the shear coefficient and could increase your chances of suffering a blister.

What Can You Do To Fix Blisters?

While prevention is always better than cure, there’re a few things you can do to help blisters heal once you have one.

The use of Compeed on a blister is great. Many runners often remove them too soon though. You must leave them on for at least 48 hours. Compeed shouldn’t be used as a blister prevention strategy either.

Wear comfortable footwear that doesn’t put pressure on the blisters (if possible).

Use felt to change the pressure points on the foot and offload the pressure around the blister.

Use cushioned insoles to reduce the peak pressures on the blisters.

Cut Race Times, Not Corners.

Racing at your potential and enjoying training is easy when you’re following the right programme.


Chafing is the annoying and often painful result of skin rubbing against skin or clothing. It can occur anywhere on your body, but the thighs, groin, underarms, and nipples are particularly vulnerable to runners.

What Causes Chafing?

Chafing is caused by friction between the skin or by an item of clothing on the skin.

What Can You Do To Prevent Chafing?

Carefully choosing your clothing and equipment is a good place to start. Make sure you buy all your gear early and practice with it in training.

With gear sorted, I’ve found that the most successful prevention plan for chafing is similar to the one I use for blisters. Some people recommend the use of talcum over the areas where you’ve experienced chafing before. Lightweight clothing or skin-fitting lycra can be beneficial so keep that in mind when making purchases.

In some cases, I have seen benefit from taping over tender body parts with sports tape.

Some people benefit from the use of lubricant, but I find that difficult to recommend because it may attract particles and could actually increase the chafe.

What Can You Do To Fix Chafing?

The soreness that people often feel following training or a race can be linked with micro tears in the skin or the onset of bacterial infection. I usually suggest a saline soak and a soothing lotion, unless there are any obvious lesions to the skin then I would suggest antibacterials.

Black Toenails

You can often recognise a runner by the state of their toenails (or lack thereof). Unfortunately, black toenails are all too common amongst the running community which is a shame because this condition is largely controllable.

What Causes Black Toenails?

Black toenails are caused by a number of things, the most common being trauma or fungal infection. Because trauma is the main cause in runners, I will focus on that.

Trauma is typically experienced in two ways.

Repetitive trauma and high impact trauma. Repetitive trauma is caused by the top of your shoe rubbing against your nail. High impact trauma is the result of or your toe slamming into the end of your shoe or dropping something heavy on your toe.

What Can You Do To Prevent Black Toenails?

The prevention of this condition has a lot to do with your gear choices.

Make sure your shoes are well fitted to your feet. To ensure this happens it’s important to purchase your shoes at the right time of the day when your feet are at their largest. This typically happens late in the day or after exercise.

Choose socks that are thin and have minimal seams as thick socks may cause too much pressure on your toenails.

Experiment with lock lacing techniques and other devices such as silicone toe protectors or toe taping techniques. These can be beneficial.

What Can You Do To Fix Black Toenails?

Sometimes black toenails don’t require fixing. In cases where there is discomfort in the nails, you can visit your podiatrist to reduce the pressure under the nail and reduce the risk of further nail damage.

However, if the nail is raised, tender or painful, I would suggest visiting your Foot Practice podiatrist. A podiatrist can assist in the aspiration of blood under the nail in a sterile environment, to reduce the risk of further infection.

Thanks, Tim.

So there you have it, some great advice for preventing (or healing), blisters, chafing and black toenails. As you can see, a lot of these conditions are controllable with a little bit of forethought and planning.

If you’d like to get in touch with Tim, his details are below.
[email protected]

+65 6909 0117

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Ben Pulham

Ben Pulham is the founder of Coached, a personalised training programme that helps runners & triathletes optimise, track and enjoy their training.