Blisters From Running: How to Treat & Prevent Blisters

Blisters From Running: How to Treat & Prevent Blisters

Blisters - a runner’s number one enemy. Blisters can be very annoying and painful for runners but despite not being a serious health risk, they can sideline a runner.

So what are blisters, how can you treat them and how do you prevent them?

To put it simply, blisters are caused by friction and look like bubbles on the upper layer of the skin. They often fill with fluid and can pop at any time exposing a spot of raw, sensitive skin. Blisters that are manually popped with an unsanitized needle can become infected and should then be treated by a medical professional immediately.


What causes blisters when running?


For runners specifically, blisters are usually caused by socks or shoes (or both) rubbing against the skin of the feet. Any friction and rubbing of material on certain areas of your feet will cause blisters.

Heat and moisture cause your feet to swell when you run thereby increasing the friction as well.

In response to the friction, the body produces a fluid around the affected area which builds up and forms a bubble on your skin. These bubbles, or blisters, sometimes pop by themselves while you’re running. When popped, the layer of skin underneath the bubble is exposed which is very sensitive and painful.

Many runners experience blisters more during races as they are running faster and perspiring more than on their training runs. The increased friction and moisture make it more likely for blisters to form.

Wearing ill-fitting running shoes can also cause blisters. Shoes that are too tight or too loose can irritate and chafe your skin, which results in foot blisters.

How to prevent blisters on the soles of your feet

Pro Tip: If you're wondering about how to prevent blisters on the soles of your feet, then listen to this episode of RUN with Coach Parry Podcast.

Can't Listen now? Read the full transcript

Welcome back to another edition of Ask Coach Parry, I’m Brad Brown, Lindsey Parry with us once again, it’s good to have you with us. 

Is Vaseline a good option for blister prevention?

Lindsey, great to have you back on and a fabulous question from Elsabe Norde and I think it’s one that a lot of runners struggle with. She says she’s battling with blisters and particularly on the soles of her feet. She says she uses double inners, she rubs on lots of Vaseline, lots of walking and less running. Would that help or how can she go about sorting those blisters out?

Lindsey Parry: Look, there’s a couple of things that need to be done and it does depend a little bit exactly where the blisters are. So Vaseline that she’s already trying is one of the things that normally works, but unfortunately because the shoe is material, it will eventually absorb that petroleum jelly. Then whatever or wherever it’s catching or chaffing on the shoe, you’re going to get those blisters again. So there are a couple of options that can be explored.

The wrong sized shoe may be leading to blisters

The first is to make sure the shoe is the right size. If the shoe is too tight or if the shoe is too loose, so either too small or too big, both of those can lead to blistering. What you want to do is, put the shoe on, tie the laces so that they are reasonably snug, but not too tight. You want to be able to fit your thumb between your heel and the shoe, but it shouldn’t be loose. You should be able to get your thumb in there without like really forcing it in, but it shouldn’t be loose. If you’ve got that, you’re probably in the right pair of shoes, you’re going to get a little bit of movement, but not too much.

The next thing then is to have a look at the socks. You want really, nice, thin, breathable socks and if you are in the right pair of socks but you’re still getting blisters, then there are a few more options that you can exercise. So you can take a thin double layer sock, there are not too many stockists in South Africa that sell those, but if you get very thin, double layer socks, then the friction will take place between the socks rather than between your foot and the sock or your foot and the shoe.

Can special socks stop toes blistering?

That’s the first thing and if the blistering is in the toes, you actually get socks now with individual toes and so then the chaffing will happen again between the socks rather than between your two toes and that should stop the blistering.

Then the final thing that you can do is actually to do a little bit of modification of the shoe. If it’s catching on a particular point and provided it’s not the sole, so it’s not underneath the foot. If it’s on the side of the foot or on the toes, you can actually cut away part of that shoe and that’ll stop the friction happening at that point of contact and that’ll also help to largely reduce that blistering.

BB: Awesome stuff Lindsey, Bruce Fordyce tells a funny story about how he used to put sunroofs on his shoes, brand new pair of shoes, cut the toe box off and you’re good to go. I hope that helps. Don’t forget to use that #AchieveMore. Up for grabs, Nokia Lumia 640, also a brand new Fitbit. If you are training this week, pop it onto social media, tell us exactly what you did and don’t forget the hashtag. We’re back again in just a couple of days time. From myself, Brad Brown and Lindsey Parry, it’s cheers.

Types of blisters from running


There are essentially three types of blisters you get from running that you need to be aware of:

Common blisters:

Common blisters are the kind of blisters that most runners experience. They are bubbles of skin that usually pop by themselves and leave some raw skin exposed. These blisters are usually quite pale in colour and can be a few shades lighter than one’s skin colour.

Blood blisters:

Blood blisters are more uncommon in runners as they are caused by the pinching of skin without breaking its surface. Blood blisters usually only occur if your shoes are too small or a small stone finds its way into your shoe while running.

However, friction and chafing can also lead to blood blisters if the underlying blood vessels get damaged. When the friction or pressure on the affected area breaks the blood vessels, it causes blood to mix with the clear fluid in the blister. This makes the blister appear red or purple in colour.

Infected blisters:

A blister gets infected after being drained improperly or popped with an unsanitary needle. Infected blisters turn yellow, green, brown, blue or black, fills with pus and the surrounding area will feel warm. If you think you may have an infected blister, go and see your doctor immediately.


How to treat blisters from running


Small blisters generally require very little treatment and will heal up by themselves over time.

You can cover your blister with a plaster or band aid & bandage to prevent more friction from occurring while you walk or run. Small blood blisters should also be left alone to heal in their own time. There are also many products on the market that you can use like blister patches or blister shields.

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If you start to feel a blister forming during a race, get medical assistance as soon as you can. Stop at one of the medical stations to tape or bandage it up before it gets too painful. If you feel one coming on during a workout, you should consider ending your workout early to prevent it from fully forming. This will allow it to heal quicker and you can get back to training in no time.

One way you can stop the blister from getting worse is to cut a hole the size of your blister in some moleskin. Place it around your blister and then cover it with a bandage. This moleskin doughnut will prevent any further friction and the blister will then dry up and start to heal on its own.

Popping small, mild blisters exposes raw skin to bacteria and opens it up to a risk of infection. If you blister does pop by itself, make sure you keep the area clean and replace your bandage or plaster daily.

Can a change of running surface cause blisters?

Pro Tip: A change of running surface ie from road to trail can cause blisters too. Moisture can also be be contributing factor if you're running on wet trails. Listen to this podcast to find out why...

Can't Listen now? Read the full transcript

Brad Brown: Welcome back to this edition of Ask Coach Parry. Lindsey Parry with us once again, still in Chicago, Illinois, ahead of this weekend’s WTS World Triathlon Series that’s taking place there. Lindsey, welcome back and a question in from Brian Gibbon today. Brian is struggling with blisters and he wants to know if it could be a function of being in the incorrect shoe size?

I can give you a bit of background. Brian does a lot of trail running as well, him and his wife Lisa have just completed their third Wild Coast Wild Run. So lots of trail there, lots of running in wet shoes as well, so that could also cause it. What do you reckon, it’s difficult to say without seeing him, but could it be that his shoes are either too big or too small, could that cause blisters or could it also just be a function of what he’s running on?

Lindsey Parry: I think it’s because Brian left us in Gauteng and he’s living in Cape Town. I think he’s getting a little bit of penance for being selfish. He is a pretty experienced runner, so it could be the change up from spending a lot of running on tar and now doing a lot of running off road.

Movement causes blisters

So there is more movement in the shoe and that’s part of the reason why a lot of the really good off road shoes do have a slightly more minimalist feel to them. You tend to want them sitting a little more snug on your feet so that there is less movement because that’s really, at the end of the day, that’s what’s causing blisters.

So the movement is causing it and the particular shoes that you are running in may also have a stitch or a seam or a pressure point or something that because of your particular biomechanics then leads to blistering. The first thing that I would check, because they have made the move from more on road running to much more off road running and now that they live in CT means that a lot of their training will move to that. Is are you in the right shoes for the terrain that you’re running on?

Are the shoes comfortable and in terms of the off road market, there is a wide variety of shoes. So that perhaps also means trying, if you’re very happy in your on road shoe brand, that doesn’t mean that the same brand is going to work really well for you when you move to off road.

Moisture is not your friend when it comes to blisters

You alluded to it earlier too, wet socks and wet shoes are going to be a big problem, particularly in off road racing, it will often take you through water crossings. I would carry dry socks with me. So that after a river crossing, after you’ve run a little bit and gotten the majority of the moisture out of the shoe and the shoe is now more damp; is to actually stop and get a fresh pair of socks onto the feet so that you don’t get that blistering.

Then obviously the other thing we’ve discussed many times with road running is to potentially look at actually modifying and cutting the shoe at those pressure points to try and reduce the friction so that you can stop your feet from blistering.

BB: There you go Brian, the short answer is, you shouldn’t have moved to Cape Town. Emigration is complete and hopefully I don’t suffer the same fate now that I’m living in CT as well. Thank you very much for that question, we look forward to hearing from you again. Don’t forget, you can get your question in, just head over to the website,, you can submit them there and who knows, we could be answering them on the next edition of the podcast. Until then, from myself, Brad Brown and Lindsey Parry, it’s cheers.

If you have a more severe, painful blister that is preventing you from running or even wearing your shoes, you may consider draining the blister. If you feel like you need to drain your blister, you should contact a medical professional. Someone with a sports medicine background will be able to get you back on the road or trail in no time.

If, for some reason, you cannot see your doctor, it is possible to safely drain the blister yourself. However, it is highly recommended to see your doctor instead of doing it yourself. Draining your own blister should only be done as a last resort and only if your blister is causing unbearable pain.

To drain a blister, first, you will need to wash your hands and the blister with soap. Then sanitize the blister and surrounding skin with an antiseptic (eg. rubbing alcohol) and sterilize a sharp needle with the antiseptic as well or boil it in hot water for 5-10 minutes.

Gently pierce the blister with the needle in a few places around the edge of the blister to drain the fluid. Very gentle pressure can be applied to help drain the fluid. It is very important to leave the overlying skin intact.

Then apply an antiseptic cream or ointment to the area and cover with a plaster or bandage to protect the area. Apply a new bandage daily and keep an eye out for any signs of infection. If you notice any redness or pus, go and see your doctor immediately.

Do not try to drain a blood blister. If a blood blister is causing you pain, go and see a medical professional for treatment advice.


How to prevent blisters when running


As horrible as blisters are, the good news is there are some things you can do to prevent getting them when you run.

Wear proper-fitting shoes

Make sure your running shoes aren’t too small or too big. Since your feet swell as you run, your shoes should be about half a size to a full size bigger than your normal shoe size. There should be some wiggle room around your toes too. When buying your running shoes, it's worthwhile visiting a specialist running store to make sure your shoe fits correctly.


You should wear socks that are specifically made for running as they are made from synthetic materials that wick moisture away from your feet. Avoid socks made from materials like wool as cotton as they get very moist and will cause more chafing.

Running socks are also shaped better to fit the feet properly. This prevents the material from bunching up around the toes, causing hot spots and rubbing against the skin.

Double layer socks are also a great prevention method when it comes to blisters. Some running socks have a double layer which is specifically designed to prevent blisters from forming. The two layers rub against each other rather than chafing against the skin. This reduces friction and thereby preventing blisters from occurring.

Tape or bandages

Many runners will use athletic tape or moleskin over known problem areas of the foot to ensure that there is no rubbing on the skin. If you use some sort of tape, make sure you apply it smoothly. Believe it or not, some runners swear by the use of duct tape to prevent blisters from running too.

Use a balm or lubricant

There are some special balms made specifically to prevent chafing, but Vaseline would also work just fine. Apply the balm around problem areas to prevent blisters. The balm acts as a protective layer between your skin and the material of your socks.

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