4 Reasons Why You're Coughing Up Mucus After Exercise

If you are coughing up phlegm after running, you might need to look into it.
Image Credit: Thomas Barwick/Stone/GettyImages

Crushing your mile time or hitting a new max during a set of deadlifts calls for a celebration. Unfortunately, for some people, this post-workout time is spent ridding their body of excess phlegm. If you're coughing up mucus after exercise, it's time to figure out what's causing it, and how to cope.


To help you get to the bottom of your excessive phlegm, here are some common reasons why you're so mucusy after exercise (and what causes the mucus).

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1. You Have Allergic Rhinitis

If you're susceptible to environmental or seasonal allergies, you may find that coughing up mucus after exercise is a common occurrence. Indeed, an indoor or outdoor workout can expose you to allergens like pollen, dust and mold that can cause mucus, according to Harvard Health Publishing.

More specifically, exposure to an allergen can cause your blood vessels to swell, resulting in nasal congestion, an overproduction of phlegm and coughing up mucus after running or other activity.

One way to minimize the effects of allergic rhinitis is to avoid the allergen. For example, if pollen is the culprit, take your running or cycling indoors when levels are high. Or if you find there's something in your gym that's triggering a reaction, such as mold, you may need to find another place to work out. When exercising at home, make sure the room you're using is dust-free — or at least clean — to help reduce symptoms like nasal congestion, coughing and phlegm after running.



While certain exercise conditions can lead you to cough up phlegm after running without cause for concern, if your symptoms get worse or you can't find relief, talk to your doctor to get to the bottom of your symptoms, per the Mayo Clinic.

2. You're Breathing Heavily

When you exercise, you're often breathing faster or more heavily. And this increased respiration in and out of your mouth can dry and cool your airways (especially if you're working out in the cold), according to Johns Hopkins Medicine.

This can trigger your body to produce extra mucus to lubricate dry tissue. The result: coughing up mucus after exercise.


Staying hydrated before, during and after an aerobic workout may decrease your mucusy symptoms and help you avoid phlegm while running.

3. You Have a Respiratory Condition

It's not uncommon to hear a fellow gym-goer hacking up a snot rocket on the treadmill, especially during cold season. After all, many people continue to exercise while sick.



But an overproduction of mucus during and after exercise may be a sign you're headed towards respiratory illness, according to the Mayo Clinic. For instance, certain infections like bronchitis can lead to hard phlegm, coughing and chest congestion, especially during exercise, per the Mayo Clinic.

Whether or not you should continue exercising while sick is dependent on your symptoms. In general, if your symptoms are above the neck (like a runny nose, sneezing, a minor sore throat or congestion), then it's probably OK to work out, according to the Mayo Clinic.


But if those symptoms creep down your body (aka below the neck, like chest congestion or nausea from the flu), it's time to take a break and rest.

What Causes Excess Mucus?

Your body's defense system is what causes excess mucus in the lungs and other areas like your nose, mouth, stomach and intestines. According to the National Institutes of Health, your body creates mucus to trap and then excrete potentially harmful bacteria, viruses and dust.

4. You Have Exercise-Induced Asthma

If you often find yourself wondering why you have so much mucus in your lungs after a workout — especially during cardiovascular exercise — you may want to ask your doctor about exercise-induced bronchoconstriction (EIB).


Formerly referred to as exercise-induced asthma, EIB happens when your airways narrow during physical activity, according to the American College of Allergy, Asthma & Immunology. This can lead to symptoms like coughing and shortness of breath, both during and after exercise.

EIB can happen to anyone, not just people with asthma. In fact, an August 2018 review in the NPJ of Primary Care Respiratory Medicine reports that approximately 5 to 20 percent of people without asthma have EIB. This means that even if you don't have asthma, you can experience symptoms of EIB both during and immediately following exercise, which may be why you get chest congestion after running.


This percentage increases significantly in patients with asthma. Per the research, about 90 percent of people with an asthma diagnosis also have EIB.

Regardless, the best way to deal with persistent EIB is to visit your doctor.




Is this an emergency? If you are experiencing serious medical symptoms, please see the National Library of Medicine’s list of signs you need emergency medical attention or call 911.

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