Another runner’s rite of passage that I never wanted! The black toe thing is real!
Midlife Mile
One of the things no one warns you about when you start running — especially in your forties — is just how badly your feet are going to suffer. You expect the knees, maybe your back, maybe some mid-run regret. What you don’t expect is to look down after a run and see that one of your toenails has quietly turned the colour of a bruise you’d usually associate with falling down stairs.
It was my right foot. Second toe. I noticed it by accident — took off my sock, glanced down, and froze. The nail looked dark, slightly raised, and not at all how I remembered it. For a brief moment I thought I’d dropped something on it without noticing. But no — it turns out I’d joined an exclusive club I never applied to: the black toenail brigade.
Apparently, this is a thing
A quick search confirmed it. Black toenails — caused by repetitive trauma during running — are pretty common, especially for newer runners doing longer distances or anyone wearing shoes that don’t quite fit.
In my case, I think I ticked all the boxes:
- Slightly too-small trainers
- Poor lacing
- A few hilly routes where my toes kept sliding forwards
Every step was like a little tap against the inside of my shoe. One or two taps? No big deal. Thousands, over several runs? Blood under the nail, pressure, bruising. Eventually the nail lifts. And yes — it does fall off, by the way. Mine came away quietly one day in the shower. New one was already growing underneath. Still a bit weird.
The sock lesson I learned too late
Here’s something else no one mentioned: cheap socks make this worse. I’d been running in whatever was clean. Cotton, old gym socks, the occasional rogue ankle sock with no grip.
It turns out your socks really matter — especially if you want to avoid rubbing, heat, and extra pressure in your shoes.
The ones that worked for me:
- Proper running socks with light cushioning
- Moisture-wicking fabric
- Seamless toes (this makes a difference, trust me)
- Snug fit around the midfoot so they don’t bunch
I switched to a few pairs like these:
Since switching, no blisters, no sliding, and no repeat toenail trauma. Lesson learned.
The advice that actually helped: the runner’s knot
After my toenail drama, I wandered into a local running shop half expecting them to recommend new shoes. But the guy looked at my lacing and said, “Mate, have you tried a runner’s knot?”
I’d never even heard of it.
Turns out it’s a way of lacing your shoes that helps lock your heel in place — stops your foot from sliding forward during runs, especially downhill. You use the extra hole at the top of your shoe (the one no one ever uses), loop the laces back through, and tie it off like normal.
It took five minutes to learn. Since doing it, I’ve had no toe bruising, even on long runs. And I’m still using the same shoes. So if your toes are taking a beating and you’re already in decent runners, try that first.
Here’s a good guide if you want to see how it works:
Should you be worried if it happens?
Not really — unless it’s very painful or infected. For most of us, it’s just an annoying, slightly gross milestone. Mine didn’t hurt. Just looked grim. I kept it clean, left it alone, and eventually it sorted itself out.
I’ve still got one nail that doesn’t look quite right, but it’s not stopping me running — and that’s the main thing.
Now for the gross but, and what my toenail actually looked like:
Final thoughts from someone missing a toenail
If you’re new to running and this happens, don’t panic. Don’t stop. Just fix what caused it — probably your shoes, your laces, or your socks — and carry on.
Because the truth is, it’s not a sign you’re failing. It’s a sign you’ve stuck at this long enough to get the kind of injury that only actual runners get. And once you’ve made peace with the fact your toes might occasionally look like bruised grapes, it becomes just another weird part of the process.
Welcome to the club. Mind your socks.