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?

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.

Let’s dive deep into everything a runner or non-runner needs to know about blisters…

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. 

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.

It’s important to make sure that your 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. 

When trying shoes on you should: Put the shoe on, and tie your laces so that they are reasonably snug but not too tight. You should be able to fit your thumb between your heel and the shoe and it should not be loose. If you can do this without forcing your thumb in with difficulty then you’ve got the right size.

This short video will explain exactly how to make sure your shoes fit correctly…

Does Vaseline Work For Preventing Blisters?

There are a couple of things that need to be done to prevent getting blisters and it does depend on exactly where the blisters are. 

Vaseline is one of the things that normally work, but unfortunately, because running shoes are made of material, the petroleum jelly will eventually absorb into the shoe itself.

Resulting in you still getting blisters… other options need to be explored that would work better at preventing your blisters.

Can Toe Socks Prevent Blisters Between Your Toes?

For blisters on your toes, you can actually get socks with individual toes so that the chaffing will happen between the socks rather than between your two toes.

Types Of Running Blisters

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 and can be a few shades lighter than one’s skin color.

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 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.

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, fill 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 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.

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 your blister does pop by itself, make sure you keep the area clean and replace your bandage or plaster daily.

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 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 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.

Moisture Is Not Your Friend When It Comes To Blisters

Wet socks and wet shoes are a big problem when it comes to blisters.

If you’re into trail running, I would carry a pair of dry socks with me so that after a river crossing and after you’ve run a bit to get the moisture out of your shoe, you can top and put a fresh pair of socks on to prevent blisters.

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.

  1. 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.

  1. Socks

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 or 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 prevents blisters from occurring.

  1. 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.

  1. 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.


Devlin Eyden has a passion for seeing his athletes grow and excel. From novice runners or cyclists across all disciplines to elite mountain bikers representing South Africa at World Championships. In addition to helping you ride faster, for longer, Devlin also has the personal touch when it comes to your bike setup, aiming at improving the overall rider experience. With his background as a Sport Scientist as well as a Strength & Conditioning specialist, performance is Devlin’s main priority, be it in the gym, the lab or out on the road or trails. Being a keen runner & cyclist and having completed the Cape Epic among others, Devlin has first hand experience in what it take to reach your goals. If you’re looking for a once-off training program or ongoing, high touch support Devlin has you covered.

Comments are closed.