Dealing With Blisters After Running a Marathon

Posted May 05, 2026 in Running

Blisters are a common occurrence for anyone who’s on their feet–runners especially. This blog discusses blisters during a marathon: how they appear, how to prevent and treat them, and why they seem to pop up specifically on race day.

6 Min Read:

Table of Contents

• Running With Blisters
• How to Care for Your Post-Marathon Blisters
• What to Do When a Blister Pops Up in the Middle of a Marathon
• Why Are Blisters More Common During a Marathon?
• How to Prevent Blisters

Running With Blisters

If you’re a seasoned marathon runner, then you’re no stranger to the pain and frustration of blisters. These small bumps on your feet, toes, and heels can crop up any time you have a specific combination of friction, moisture, and heat—becoming especially common during long runs like marathons. 

Blisters, while painful, are both common and relatively harmless when properly cared for. They occur when the top layer of skin, the epidermis, pulls away from the middle layer, the dermis. In between is a layer of sterile fluid, which your body creates to protect itself and reduce friction and damage. The pain is also a signal to you to stop whatever you’re doing that’s causing the blister, but that’s not realistic when it comes to running a marathon. 

How to Care for Your Post-Marathon Blisters

Blisters only become a concern when they are infected, so if they appear after your marathon, here’s what to do: 

• Leave small blisters alone. Let your body do what it does best and heal itself. Small blisters are rarely a concern, unless they become larger or show signs of infection.

• Do not pop your blisters. That fluid is there for a reason!

• Shallow, small, or early blisters can be protected with a layer of tape or moleskin. This can prevent further friction and may even improve the discomfort you are experiencing.

• Watch for signs of infection such as: redness, pus instead of clear fluid, blood, increased pain, swelling, or warmth. 

If your blister pops on its own, here’s what to do: 

• Gently clean the area with mild soap and water.

• Keep it clean, dry, and protected with an antibiotic ointment and a bandage.

• Do not remove the flap of skin; this protects the soft new skin underneath.

• After a few days, the hardened flap of dead skin can be removed with medical scissors or nail clippers. Make sure all tools are disinfected first, and do not rip or pull the skin.

What to Do When a Blister Pops Up in the Middle of a Marathon

You’ve likely been training for months for this race, and most runners won’t let a blister stop them. In a majority of cases, it’s perfectly safe to continue with your run if you notice a blister. But if you experience the following symptoms, you might need to take a break or stop altogether: 

• If it changes your gait. If you find yourself babying the area of your foot that has the blister by favoring another part, you can accidentally cause injury to yourself. If this is the case, you might need to stop and address the issue before continuing the race.

• If the pain is severe or in a high-impact area of your foot, like the ball. If you develop a monster of a blister, or it’s in a location that may cause it to pop mid-race, it’s best to sit this one out and deal with your blister as best you can to avoid infection.

• Signs of infection. If you notice swelling, redness, or pus in the area, you need to exit the race and seek medical attention immediately.

Mid-Run Fixes

Once you assess your blister and deem it safe to keep going, you can patch yourself up to finish the race by reducing friction with vaseline or petroleum jelly, swapping wet socks for dry ones, and applying a hydrocolloid patch to protect the area for the rest of your run.

Why Are Blisters More Common During a Marathon?

The obvious answer is that running over 26 miles, typically over four to five hours, creates a lot of friction on your feet, thereby increasing your risk of blisters. But many runners note that race-day blisters are much more common than on training days, which, for marathon training, are daily. So why do they seem to appear during the most inconvenient times?

There are a few factors: 

• Race-day jitters and anxiety can increase sweating, which creates an ideal environment for blisters.

• Starting the race with wet socks from pre-race sweating sets you up for blisters by the halfway point.

• Most runners don’t douse themselves with water during training, which is a common cooling-off method during marathons. Water can get into their socks and shoes during race day due to this.

• You’re going to be pushing yourself harder on race day; it’s what you’ve been training for! Increased friction can increase the risk of blisters when you’re giving it your all.

• An unfortunate number of runners wear brand-new gear on race day, and stiff shoes are a leading cause of blisters.

Obviously, blisters pop up during training as well, but if you feel that you have a race-day curse of the blister, hopefully the factors above make you feel a little better. 

How to Prevent Blisters

The best treatment for blisters is prevention, and deterring their common causes is your best bet for race-day comfort.

• Find running shoes that fit. An ill-fitting shoe can cause far more serious issues than blisters alone, and your feet are your most important asset.

• Break in new footwear. Race day is not the best day to test your new shoes; give them time to soften the material and mold to your feet for optimal comfort and minimal friction.

• Wear moisture-wicking socks. Synthetic materials and merino wool are considered the best.

• Inspect your feet for hot spots, calluses, or other minor issues. You can identify where the most friction is and protect that area. This is also just good practice for maintaining the health of your feet.

Want to Learn More About Protecting Your Feet During a Marathon?

Dr. Ethan Ciment at Chelsea Foot and Ankle is not only an experienced podiatrist and podiatric surgeon, but also a seasoned athlete and runner himself. Caring for your feet is an essential part of your overall health, and for runners, it’s everything. 

Contact Dr. Ciment today at (646) 929-4149 or complete the contact form to schedule a consultation to assess your foot health, get help with common sports injuries, or be fitted for custom orthotics to keep you running and moving your best.