Toenails, Calluses, and the Stuff No One Wants to Talk About

Your feet work hard for every mile you run — but the issues runners often ignore are the ones that cause the biggest setbacks.

In this episode of The Runner’s Sole Podcast, Sharon Miller dives into the topics most runners avoid discussing: toenails, calluses, sweaty feet, and everyday skin problems that can silently derail your running journey — especially for diabetic runners.

From black toenails and fungal confusion to dangerous callus buildup and moisture-related infections, this episode explains why small foot issues should never be ignored. Sharon shares real patient stories, practical prevention strategies, and simple routines that protect foot health long-term.

You’ll learn how proper nail care, safe callus management, and smart skincare habits can prevent infections, reduce injury risk, and keep you running consistently for years to come.

Whether you’re managing diabetes or simply want healthier running habits, this episode gives clear, science-based guidance you can apply immediately.

🎧 IN THIS EPISODE YOU’LL LEARN:

✅ How runners should safely care for toenails
 ✅ Difference between nail trauma and fungal infection
 ✅ Proper nail trimming techniques to avoid ingrown nails
 ✅ Why calluses can become dangerous for diabetic runners
 ✅ Safe ways to manage thick skin and pressure points
 ✅ Moisturizing routines that actually protect your feet
 ✅ Causes and solutions for sweaty feet
 ✅ Daily habits that prevent infections and skin breakdown

👣 WHY THIS EPISODE MATTERS

Foot problems rarely start big — they start small and unnoticed.

For runners, especially those living with diabetes, ignoring toenails, skin care, or moisture issues can quickly lead to infections, forced training breaks, or long-term complications.

Simple daily habits can protect mobility, confidence, and longevity in running.

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🏃 ABOUT THE PODCAST

The Runner’s Sole Podcast is where running meets science, stride by stride.

Hosted by podiatrist and runner Sharon Miller, the show helps runners understand foot health, prevent injuries, and build sustainable running habits for lifelong movement.

Transcript

SPEAKER_00 0:18

Welcome back to Runner Soul, where running meets science stride by stride. I'm Sharon, a resident podiatrist, runner, and unapologetic foot nerd. So what do we have in store today? Well today is season four, episode four, and we'll be talking all things toenails, calluses, and the stuff no one wants to talk about like sweaty feet. Now in our last episode we talked about blood sugar levels, we talked about blisters and timing your runs. So today we're going somewhere a little bit personal. Yes, we're going to talk about toenails, calluses, and foot skin issues, things most runners quietly ignore and quietly suffer with until they become a major problem. Now if this sounds a little gross, but if you are running with diabetes or even just love running, these issues you cannot ignore because your feet will carry you through every single mile, and one small little neglect can lead to weeks off the pavement. So by the end of this episode, you'll know how to safely care for your toenails, manage calluses without hurting yourself or doing anything silly like taking a knife to your foot, and establish easy, simple routines that will keep your feet healthy and strong. Well into your 80s, nineties, and hopefully one hundreds. Now toenails might not be glamorous, but they are surprisingly important for runners. And like all things in the body, they are there for a reason. And I'll explain what the role of your nails are. So black nails usually they're caused by trauma or pressure, but sometimes it can also hide infection. Also, you can sometimes have pus or bleeding underneath, and all you see is black nails, but you've no idea what's actually going on on the nail beds, so you know that can cause your problems. Then we have nails that are discolored, you know, thick, yellow, not very nice to look at. So most of the time it could be fungus, but also it can be caused from trauma. So you know those little micro trauma that you get in your shoes from running. You can even get it from you know just running on the running machine. It doesn't take a lot to damage the nails. So fungus versus trauma. And as we said, not all discolored nails are fungal. Trauma from the shoes or the repetitive stress can look the same. So correct diagnosis really matters, and then of course, we've got the ingrown toenails, that is very common. So safe trimming techniques is very important. So you should definitely cut straight across, avoid digging into the corners unless it's necessary. For some people, they have what we call involuted nails, and that is when the skin starts to grow over the nail, the nail gets hidden, and lo and behold, the nail will just keep on growing. So if you have corners like that, then of course the corners have to be removed. But otherwise, please don't dig into your corners, and definitely don't pick at your nails. And please use a proper nail clipper. Don't rush your nails. You know, they seem to be those things down there that are not essential, they're a bit of a pain, you've got to, you know, keep cutting them every now and again. But please don't rush because small mistakes can lead to ingrown nails or infections, and we don't want you getting into trouble, and we don't want something minor like that just causing you problems, and then before you know it, you're off those poor feet. Now, one of my patients, Leo, was a type 2 diabetic and loved to do his half marathons. Now, he'd been ignoring his black toenails for months, thinking they were harmless, thinking oh yeah, they'll get better, whatever. But one race later, the nail lifted, caused a pain, infection, and a forced break from running. So once we trimmed them properly, cut them right back, treated everything that was happening underneath the nail because you can't see what's happening underneath the nail. So we treated the infection and adjusted the shoes, and he was able to run as normal. But the lesson stuck. Toenails are not optional care, they are essential care. So please do look after them because if you're diabetic, you know, one small little infection from your nails, you can't it can lead to amputation quite easily, and then that's gonna have implications for your mobility and for your running in the future because a big toe has a very important role in gait, in stability, and we need those big toes very much. We can do without the little toes, one little toe chopped off won't matter too much, but the big toe now that will cause your problems. So please check your toenails weekly. Look for discoloration, thickening, separation, look for signs that maybe the nail might be loose, and please trim them safely. And if you are unsure, please see a podiatrist before it turns into a bigger problem. Or you can book a consultation with ourselves. So let's move on to calluses, which are very, very common, and I'm sure everybody listening knows what a callus is. So calluses are tricky, they're slippery little fish because your body, yes, does create them as a natural response to friction, but in diabetic runners, they can increase pressure instead of protecting it. So calluses they're not always protection, especially for diabetic people. Now, why thick skin can be dangerous? Well, for the simple reason, it's all down to pressure. The pressure bills under the hardened layer create a hidden stress that can cause ulcers. And of course, once the skin is broken, then you are in trouble. And of course, with a callus on top, it looks, you know, it just looks like you know, it's no big deal. But we have to release the pressure and the callus to see what exactly is going on underneath. Many a time I have reduced the callus to find a huge ulcer underneath. Sometimes even the bone is like sticking out from the ulcer, and of course, you can't see all that with a big daub of callus on top. So please, please don't let that callus build up. So safe management of the callus. Well, gently using a pumy stone after a bath when your feet are soft after the water. Also, it's good to put some Epsom salts in your in your bath, and that really helps the skin, you know, to remove the skin quite easily. Of course, if you're having a foot bath, we don't want you to be soaking your skin for too long because when you've been diabetic, don't want the skin to become too macerated. But you can baby feed for five minutes with three to four dessert spoonfuls of Epsom salts. As long as you remember to dry between your toes. Pay particular attention when you're drying underneath your toes because that is where moisture gathers, and then again we've got tissue breakdown, uh, becomes macerated, and then it goes to tiny. So we're looking at the safe management. So if you can't manage it yourself or you're afraid to, I'd suggest seek a podiatrist who can safely debride if you've got lots of thickened callus or corns. So please, please, please do not use razors, home acids, or DIY aggressive treatments. No! Like the drill that you have in your toolbox. No, no, no, please don't use that because they can seriously backfire. So let me tell you about Maria. Maria was a type 1 diabetic runner who had thick calluses on her forefoot. She tried shaving them down with a blade at home, and within days she developed redness and swelling that required medical attention. So once we treated it professionally and added proper cushioning in her shoes, she was able to return to training quickly and safely. So my practical tip is soak the feet before gentle pumice stone filing. Now I mean gentle, and use the Epsom salts, as I say, because that will that's very helpful. And then make sure you moisturize afterwards, but please don't put any moisture between the toes. So, yes, by all means, put some moisture on the heels because that's very important, and a little bit over the rest of your feet, but not between your toes. No, because that is just providing the perfect environment for fungus, and we don't want that. And then the other thing is try to cushion high pressure areas with gel pads or even band-aids. You can get like band-aids that have that have a lot of like cushioning in them, and if you feel that you have these particular pressure areas, then it would be better to protect them before a run because prevention is better than cure. So we want you to cushion those high pressure areas before a run, and or make sure you have properly fitted shoes. You see, people think because they're in trainers that trainers are the best, and I agree they are, but not all trainers are made the same. There are some trainers that just really don't have an awful lot of support in them. So we've got to look at what you're wearing as well. So we do know that healthy skin is the foundation for avoiding blisters, cracks, infections, and any breaks in the skin. Because once your skin is intact, then you are protected from the outside world because, as we know, there's lots of germs out there, bacteria, all sorts of things, fungus, and so if you have a teeny little break in your skin, then anything outside can get inside, and that includes things like cellulitis. Cellulitis, all that takes for cellulitis to form, is teeny tiny little break in the skin, a scratch that you can hardly even see. So please let's try and have a good skincare routine. When it comes to moisturizers, it's good to have ingredients like urea or glycerin because they work really well, especially urea. Now it does mean that your moisturizer will probably be a little bit more expensive if it's got urea in it, but it is definitely well worth it. Because isn't it better for your skin to clear up quickly than for you to put on say cheap emollients, and yes, it will heal up, but it's going to take longer. So we want moisturizers with urea or glycerin. So when not to moisturize, well, as we said, never moisturize between the toes because it can trap moisture and invite fungal infections, bacteria, etc. etc. So we have to also look at seasonal changes because cold or dry weather increases skin cracking, hot or humid weather increases sweat-related issues. So whether it's too hot or too cold, the skin will break and it won't be able to cope. So do adapt your routine accordingly. A quick routine recommendation is as always, wash your feet daily with mild soap or better still, some Epsom salts. Make sure you dry thoroughly, especially between those little tootsies, because sometimes, myself included, your toes can be, you know, very kind of close together, and there's not much room between them. And of course, if they're all bunched together, then even more reason for the fungus and moisture to get trapped. So only apply the moisturizer on top of the foot, in the heel, and a bit in the sole, but just not between the toes. And always check for cracks, redness, peeling, any kind of changes to your skin, even like little nicks, because it's really important that we take action straight away and not allow anything to fester. Now, one of my patients, Amit, who is the type 2 diabetic runner, he had problems with his heels because he found that they seemed to be cracking in winter. Sometimes he he felt like you know somebody had got a machete to them and just hack hack hack. He had all these little hacks in uh at the side of his um heels which started to open and it became it became quite painful actually. So he came to see me and we reduced all that overlying callus, got right down to the um nitty-gritty, and then I gave him a simple moisturizer routine. It was like moisturizer, it had um urea in it, and then he put on his protective socks every night before he went to bed. So he put his cream on, then his protective socks, and that made a huge difference because it's all about consistency, you know. Don't wait until you've got this massive problem to solve, just a little bit of maintenance um every day, and before you go to bed at night is a great time because you just slap on a bit of cream and then you sleep for your eight hours, and then as you're sleeping, your skin is renewing itself, and you're putting the moisture on it, so it's then getting protection. And so we leave sweaty feet to last. As we know, sweaty feet is a common condition where the sweat glands in the feet are overactive, and this produces more moisture than is what's necessary for temperature regulation. Now, most people experience this occasionally, but some face a very chronic, uncomfortable and often embarrassing issue where they're just smelly, smelly all the time. Socks are smelly, the shoes are smelly, and of course then partners start to complain. Which isn't good. So, why do feet sweat? Well, there's lots of reasons, and especially if you're diabetic, it's very common to have either overly sweaty feet or very dry skin. You know, there's no sometimes there's no in-between, it's like one or the other. So, one of the reasons that causes it is the overactive glands. It's when the sweat glands work over time for no apparent reason, often affecting the feet and the palms. Also, heat and activities, high temperatures, exercise, obviously, when you're running, that does increase your temperature. And physical exertion, such as standing all day, increases the sweat production. Also, believe it or not, emotional stress. The sweat glands on the soles of the feet react to emotions, meaning anxiety and stress can really trigger sweaty feet. So if you feel you're in a stressful situation, if you're at work, just make sure you breathe. Don't forget to breathe, take deep breaths, and drink plenty of water. And then we have hormonal changes. Now, this is very common in adolescents and pregnant women because their hormones are all over the place. And then also your footwear has a lot to do with it because synthetic materials are kind of you know plasticky vinyl, and tight shoes, they actually prevent evaporation from taking place. So it's locking in that moisture even more, and your your feet and your shoes don't have a chance to breathe. And also some underlying medical conditions, like diabetes, like we talked about, is very, very common. Thyroid problems, infections, and lots more reasons. So if you find that you're you've got a lot of odor, that means the bacteria on the skin is thriving in your damp environments, breaking down the sweat and causing an odor. Fungal infections, such as athlete's foot, thrive in moist, dark environments. So it's just a breathing ground. And then for people who get blisters and skin breakdowns, it can also be due to having sweaty feet because the excessive moisture. Increases that skin friction, leading to a higher risk of painful blisters and skin softening, which isn't good, of course. So tips for management and prevention. Well, we talked about your daily hygiene about washing your feet daily with um a mild soap and etin salt and drying between the toes, so that's very important. You can also apply foot powder or cornstarch, which will absorb the moisture, and even a little bit of bicarbonate soda is really good as well. So don't forget to choose breathable footwear. So wear leather or canvas shoes and rotate your shoes to allow them to dry for 24 hours. If it's nice and sunny, which is probably unlikely if you're living in Scotland, but when you do see the sun, cut those shoes out. And also look at the kind of socks you you're wearing. So choose wool or cotton blend socks or bamboo and change them immediately if they become damp. And another tip is to bring some extra socks to work or if you're gonna be running, and then it means during your lunch break at work you can change your socks, and then that means you're not sitting in the same socks like all day long. And then another little tip for you is antiperspirant. Now you can apply a small little amount of over-the-counter or prescription antipersant to the feet at night, and that really works as well. But if you find that all these treatment options, you've tried them all, nothing's working, then please see your GP or your podiatrist, and we can take things to the next level. In summary, we've learned all about toenails and calluses and sweaty feet. And skincare may not be glamorous topics, but they are critical for keeping your feet running strong. Small daily habits is all it takes to prevent big problems down the line. And please do join our Facebook community to share stories, ask questions, and connect with other runners. The link will be in the show notes. And please, if you would, if you have any stories or you have any tips for us, things that you've tried that's really worked, we would love to hear, and we'll share that with everybody else. And of course, if you need an online consultation about your toenails, your calluses, anything related to diabetic foot care, please visit our website. The links are in the show notes as well. So, what do we have in store for our next episode? Well, our next episode we'll be covering warning signs you should never run through. So, definitely warning sides not to be ignored. So, things we're gonna talk about things like swelling, warmth, high temperature in your skin, color changes, and silent injuries. These are all red flags diabetic runners often ignore to their peril. But recognizing them early could save your running season. So remember, every step builds resilience, confidence, and the joy of running pain-free. So keep striding, stay aware, and know that healthy feet are the foundation of a happy runner and the key to longevity. So please look after those feet and we are here as always to help that process and to make it easy for you. So good chatting with you all today, and I look forward to next episode and to reading all your stories. Keep them coming to the