Running with blisters is something most endurance athletes or weekend warriors have dealt with at some point while on a long run, in the middle of hill training or during a race. While typically small in size, these fluid-filled bubbles pack a huge ouch factor that can bring even the toughest runners to their knees.
How Do Blisters Form?
There are several potential causes of blisters in runners and other athletes. According to Brian Babka, MD, sports medicine specialist at the Northwestern Medicine Running Medicine Clinic, the most common reasons are friction, rubbing, heat and moisture, usually from exercising in poorly fitting shoes or equipment causing friction between the layers of skin and footwear or gear.
While those are the most common triggers for blisters, Dr. Babka does point out that runners and athletes should also be aware of other causes, such as burns, cold exposure and medical causes or infection, especially in athletes and runners predisposed to overtraining.
According to Harvard Health Publishing, friction blisters, which are typically the ones runners deal with, tend to occur on the feet where tight or poor-fitting shoes can rub against the skin. This friction produces the fluid-filled blisters that make running and other exercises painful. Over time, if the irritation damages small blood vessels, you may also develop blood blisters.
Read more: Remedies for Sore Feet From Running
Detecting a Blister Mid-Run
Whether you're dealing with the start of a blister or a full-blown attack from extra friction, you first need to decide whether or not running with blisters is safe. If you feel a blister forming mid-run, Brian Van Cleave, a certified personal trainer at Anatomy, says the best thing you can do is stop.
"Blisters are your feet's way of telling you that something is not right, so the best thing to do is stop, take your shoes and socks off and see what's going on," he explains. This is also a good time to adjust the laces if they are too loose and your feet are sliding around or they are too tight, causing friction between the shoe and your foot.
After a thorough check of your shoes and feet, Van Cleave says to make any adjustments you think need to be made, lace back up and hit the roads. "It may take a couple stops to find the real culprit, but it's worth taking the time to potentially prevent a blister before it becomes a problem that lands you on the couch with your feet up," he adds.
Read more: How to Find the Best Running Shoes for You
Running With Blisters
Being proactive is the best way to avoid blisters. But if you find yourself running with blisters, one thing to be aware of, says Van Cleave, is whether you're favoring the blistered foot. "Running with a limp is far more dangerous than a simple blister," he points out.
Sure, maintaining your regular running pattern and gait may be uncomfortable, but if you're going to keep on pounding the pavement, you need to adjust to the discomfort in order to avoid a more severe injury.
Gregory Kranzusch, DPM, FACFAS, a podiatrist at the Foot & Ankle Center, says that the best way to treat your blisters if you want to keep running is to use bandages. "Do not puncture a blister unless it is large, painful or likely to be further irritated," he explains.
The Mayo Clinic recommends keeping the blister intact, especially if you want to continue with physical activity. To protect a blister when running, cover it with an adhesive bandage or moleskin and make sure to place the pad so that it protects the blister.
Treating a Blister
As tempting as it may be to pinch that painful blister between your fingers, the American Academy of Dermatology (AAD) recommends leaving the blister alone since most will heal on their own in one to two weeks.
With that said, it's not always easy to be patient and wait for the healing process. That's why so many people pop and treat them on their own. If you need to treat a blister, make sure to follow guidelines set forth by the AAD or a medical doctor.
And if you have to pop a blister, Dr. Kranzusch says there are a few important steps to follow.
- Wash the area thoroughly.
- Sterilize a small needle with rubbing alcohol.
- Make a small hole and gently squeeze out the clear fluid.
- Apply a dab of hydrogen peroxide to help protect against infection.
- Do not remove the skin over a broken blister. The new skin underneath needs this protective cover.
- Cover the area with a bandage and mild compression.
The Right Gear for Prevention
Preventing blisters from happening in the first place is the ideal way to deal with them, but sometimes that's easier said than done. The good news? Experts have seen plenty of blisters, which means that there lots of tips to help get your next run off on the right foot.
For starters, make sure your gear is running-approved. That means wearing properly fitting shoes. Van Cleave says that cool, dry feet with enough space to swell naturally have a better chance of being blister-free. "A lot of runners forget that their feet will swell as they run, so while those shoes may feel great in the store, they'll suddenly feel a little tight out on the roads as your feet rub up on the inside of the shoe."
That's why it's best to go about a half size up from your usual shoe size when shopping for running shoes. That said, you also need to ensure that the shoes are not too big. If your foot slides around a lot, the ball of your foot can become a breeding ground for blisters.
But it's not just shoes that make the difference. If you want to prevent blisters, don't cheap out on your socks. Invest in a few pairs of quality, moisture-wicking socks made for runners.
Read more: 12 Essential Tips for New Runners
Other Prevention Strategies
If you're prone to blisters on certain parts of your feet, the AAD recommends using adhesive moleskin or other soft bandages to cover the blister before it gets too big. This can help protect the skin while running with blisters and serve as a preventative measure to keep them from fully developing.
In addition to bandages, some runners will also spread lubricants or antiperspirants on problem areas. While this is a common practice in many activities, Dr. Babka points out that the effectiveness of using these types of products is largely unstudied.
If you're doing all the right things, but the blisters just won't go away, then it's time to see a podiatrist or another medical doctor. They can safely drain and treat your blisters as well as work with you to come up with a plan to keep you running while your blisters are healing.
During the healing process, the AAD recommends watching for signs of an infection, such as redness, pus or increased pain or swelling. If you notice any of these red flags, make an appointment with your doctor right away.
- American Academy of Dermatology: "How to Prevent and Treat Blisters"
- The Foot and Ankle Center: "Dr. Gregory Kranzusch, D.P.M. FACFAS: Personal Interview"
- Northwestern Medicine Running Medicine Clinic: "Dr. Brian Babka, MD, Sports Medicine Specialist: Personal Interview"
- Brian Van Cleave, B.S., CSCS, ACSM-CPT: "Personal Interview"
- Mayo Clinic: "Blisters: First Aid"
- Harvard Health Publishing: "Friction Blisters"