Welcome to Earth

What is Runner's Toe?

WELCOME TO EARTH: Fartlek Training

Welcome to Welcome to Welcome to Earth! My brother has diabetes and he lives in Perth! It rhymes and it’s true. In this department, we answer a letter penned by an alien from a distant galaxy or dimension. This month’s letter comes from Zoot Sims, who everyone thought was a famous American jazz saxophonist, but, as it turns out, he was an alien visiting from the planet Cryovak, which is where he returned after ‘dying’ in 1985.

Zoot writes:


When I was living on your planet and impersonating a brilliant jazz saxophonist, I remember a conversation I had with bebop legend Sonny Stitt about his toenails going black after running the New York Marathon. He said it was called ‘Runner’s Toe’. Is that a thing, or was that cat just feeding me a line of red-hot jive?

Keep swingin’


Hey Zoot, thanks for your letter, and what a great question. Runner’s Toe—or Subungual Hematoma—is indeed a real thing, and I should know because it’s happened to me, Jason the editor, not once but twice. And as the saying goes, blacken my toenails once, shame on you. Blacken them twice—I’m a moron.

The first time my big toenails went black and fell off (it’s almost exclusively the big ones), it was the result of running in shoes with a toebox far too narrow for my wide-ass flipper feet. From memory, the shoes were Adizero Bostons, which I only ran in a couple of times before my nails turned the color of licorice. The second time it happened, I was trying to run further up on the balls of my feet because I’d read that that was a good thing. Sadly, I overdid it and basically ran a half-marathon like a ballerina. When I took my shoes off at the end, my big toenails looked like they’d been bashed with a hammer. On both occasions, my blackened toenails came away from the toe and caused me an enormous amount of discomfort, particularly at bedtime, when I would have to tape them down so they wouldn’t get caught on the sheets and make me yelp. So, Zoot, bebop legend Sonny Stitt was not pulling your leg: Runner’s Toe is a thing. But why does it happen?

Runner’s Toe is caused by blood collecting beneath the toenail, and it seems to happen mostly (but not exclusively) to athletes new to the sport. This is because their feet and toes are not used to the sudden repetitive pressure that running puts them under. So, for example, you take roughly 3,000 steps when you run for 3 kilometers, which is about 1000 steps less than you would’ve taken had you walked 3 kilometers; however, running is a higher impact activity, and unlike walking, where you tend to roll from heel to your toe, running finds you landing further up the front of your foot and rolling back toward the heel (unless you’re one of those completely insane heel strikers), so all the pressure is focused on the balls of your feet and your tootsies, which, if you’re just starting out, is hugely traumatic. You’re basically smashing them into the toe end of your shoes thousands and thousands of times, which, unsurprisingly, fucks them up.

Runner’s Toe sucks, but it’s nothing to worry about... Unless it becomes infected, and you’ll know it’s infected because it will look infected, and then it’ll begin to smell like one of Satan’s farts. If this happens, go to the doctor immediately. If it doesn’t get infected, you just have to wait for it to go away. The black will either grow out or the nail will begin to fall off. If this happens, the good news is a new nail will be growing underneath! Just like shark teeth! The other good news is the new toenails will come back thicker and stronger and better able to handle the stress you’re putting it under with this whole ‘running’ malarky. The human body is cool like that.

One final point: Runner’s Toe is avoidable. Buy running shoes that are a size up on your regular shoes (in some cases, you’ll need to go up a size and a half, but just make sure you’ve got at least 1.5cm between your big toe and the end of the shoe), and make sure your shoes aren’t too narrow for your feet.

If you’re an alien with questions about earthlings and running, write to us here!