Does running barefoot put me at risk of toenail fungus?

Hi My Running Doc!

I have heard that going barefoot in locker rooms can put me at risk of a fungal infection and toenail fungus. Does running barefoot also put me more at risk of a toenail fungus infection? 

Thanks!

Jimmy, San Francisco, CA

Hi Jimmy, 

Great question!  The short answer is no... running barefoot does not actually put you more at risk of getting a toenail fungus infection than running in running shoes.

But before we explain that, let's explain why there is such a high risk of getting a fungal infection from a gym locker room.  People work out at the gym all day long. Most of them shower once they are done. 

So the floors in the locker rooms are continually coated with water dripping off of freshly showered athletes. This leaves the floors in the gym locker rooms perpetually moist. This moisture creates the perfect environment for fungal growth. If you walk around in there barefoot the chances are good you might pick up a fungal infection in the form of athlete's foot.

The same organism that causes athlete's foot is also the same organism that causes fungal toenail infections.

In order to get a toe nail fungus infection you must have a couple of conditions present at the same time.

1. Active fungus and/or fungal spores.

2. Trauma to the toenails.

Much like a gymnasium locker room, running shoes are actually the perfect incubators for toenail fungus. Your feet are like little heaters warming up the inside of the shoes to the perfect temperature for fungal growth.  When you exercise, your feet sweat. The inside of the running shoes are also dark and devoid of sunlight. All of this creates the perfect environment for toenail fungus to grow.  

When you run, the ends of your toes and hence the toenails can bump up against the inside of the shoes. Many marathon runners have witnessed this first hand in the form of black and blue toenails after a long run. It's not a large amount of trauma, just a small amount of repetitive trauma that can cause bruising under the toenail.

If you have this sort of trauma to the toenails when you have foot fungus growing inside your running shoes, the fungal spores and live fungus can get underneath the toenail and start to grow. The result is a  fungal toenail infection.

You know you have thick yellowing discolored toenails indicative a  toenail fungus infection.

When you run barefoot you're unlikely to have trauma to the toenails in the presence of a large amount of toenail fungus or fungal spores that are often coating the inside of running shoes. And in this respect, you're actually a lower risk of getting a toenail fungus infection when running barefoot as compared to when running in heavily used running shoes.

Dr. Christopher Segler, DPM is a marathon runner and 11-time Ironman triathlon finisher.  His podiatry sports medicine practice focuses on convenient rapid treatment of running injuries. He is often invited to speak at medical conferences on the topic of barefoot running biomechanics. You can learn more about running related toenail infections and laser treatment of toenail fungus at www.LaserToenailSanFrancisco.com   If you have a question about a toenail fungus infection or barefoot running injury you can call him directly at 415-308-0833. 

What to Consider in a Minimalist Running Shoe

Hi “My Running Doc!”

I recently read the book “Born to Run.”  after reading it, I became intrigued and have decided to try some minimalist running shoes. However a lot of stuff that I read online says that might get injured if I run barefoot or in minimalist shoes. 

As a little background, I am experienced marathon runner and have been running for decades. I have a neutral foot type and never had any serious running injuries. 

Do you have any recommendations on how to safely choose minimalist running shoes so I can run with a more natural running form to convert to more of a minimalist style?

Thanks!

Peter

San Francisco, CA

Hello Peter,

Great question!  There are a number of different types of minimal running shoes that  you can choose from.  But before you can make a reasonable choice on which you would be right for you you have to understand the basics of “minimalist shoes.”

I define a minimalist running shoe as one that has lightweight construction, minimal support and a decreased forefoot to rearfoot drop. 

In case you’re not familiar with minimalist running shoe construction is important to point out that the “ forefoot to rearfoot drop” is the difference in height of the heel as compared to the forefoot. Standing barefoot is a 0° drop.  A running shoe with a zero-degree drop is flat. Any shoe that has no more supporting material under the heel than under the forefoot will have a 0° drop. 

A standard running shoe has a 12 mm drop. This means that there is 12 mm of material under the heel, lifting the heel up relative to the forefoot.  Proponents of minimalist running argue that all this extra material under your heel is what forces you to land as a heel striker when you run in these type of running shoes.

Vibram FiveFingers® are the shoes that many people think of when they hear about barefoot running.  The argument for this type of shoe is that you get the most sensitive ground feel, and hence a running experience that is the most consistent with true barefoot running. However you are protected by a pliable rubber outsole. These shoes certainly fit the criteria of a minimalist shoe in that they have very little support, they’re very light weight and they have a zero-degree drop (meaning the heel is no higher than the toes.) 

Given that most people are accustomed to walking and running in shoes that have a slightly elevated heel, they can at risk of injuries like Achilles tendinitis and even potentially stress fractures if they switch to rapidly to a barefoot running style.

There are other shoes however which will help you learn how to run without the drastic change in forefoot to rearfoot drop.  Another extremely  popular minimalist running shoe is the Saucony Kinvara. The Kinvara has a 4mm drop, is very light (7.7 oz.) and is very supple.  it allows a good ground feel and lends itself the natural running form however it still maintains a modest amount of support. It allows a bit of insurance in the sense that if reform starts to fall apart and you begin to convert into a heel striker you at least have some cushion to protect you.

Another good option is Newton Running shoes. Newton’s are unique in that they have elastomeric lugs under the forefoot that help encourage you to land as more as a forefoot or midfoot striker.  For a neutral runner like yourself, the Newton Gravity Trainer would be a good choice. It weighs 9.1 ounces and has a 3mm forefoot to rearfoot drop. Newton running shoes are designed specifically with the intent to help runners learn how to convert to more of a natural running style. In fact Danny Abshire, the founder of the company is also authored a book which helps teach runners to convert their running style away from heel striking to potentially more efficient stride. 

I think Danny has the right approach. I myself run in Newton running shoes for speed workouts and for tempo runs.

However I also incorporate a couple of different kinds of running shoes based on the workouts that I am doing. I run in Kinvaras for some moderate runs.  I also run a more of a typical cushioning type of running shoe when I do long runs, or any run where I expect that I might walk. Reason for this is simple. Most people it is spent their lives in elevated heel shoes can develop a tight Achilles tendon. Walking in shoes with a 0° drop can lead to Achilles tendinitis quite rapidly. As someone who trains continually and almost always has an Ironman on the schedule I can afford to develop any issues. I consider using multiple types of running shoes as cross training for my feet. I believe it decreases the risk of injury.

If barefoot running form is a new adventure I hope you will find it to be helpful in developing a more efficient stride and ultimately a more enjoyable running experience. 

Dr. Christopher Segler, DPM is a marathon runner, 11-time Ironman triathlon finisher and is Board Certified,  American Board of Podiatric Medicine.  He lectures at medical conferences to help teach other podiatrists and sports medicine doctors about barefoot running biomechanics and the treatment of competent running injuries. His practice is limited to runners and triathletes. He performs remote consultations for runners all over the world via telephone and Skype. He also sees patients in person in both San Francisco, CA and Houston, TX.  If you have a question about a running injury that doesn't seem to be getting better, you can reach him directly at 415-308-0833.