Many runners find themselves getting sick in the lead-up to a race, and they’re not alone. Research shows that nearly 40% of marathoners experience at least a cold in the two months prior to race day.1Nieman, D. C., Johanssen, L. M., Lee, J. W., & Arabatzis, K. (1990). Infectious episodes in runners before and after the Los Angeles Marathon. The Journal of Sports Medicine and Physical Fitness, 30(3), 316–328. https://pubmed.ncbi.nlm.nih.gov/2266764/
It doesn’t end there: in the 3 to 72 hours after a marathon, runners are also at a higher risk of illness, making it common to come down with something in the two weeks following an endurance event.2Nieman, D. C. (1997). Risk of upper respiratory tract infection in athletes: an epidemiologic and immunologic perspective. Journal of Athletic Training, 32(4), 344–349. https://pubmed.ncbi.nlm.nih.gov/16558471/
This happens because after periods of intense training or racing, the body enters a state of temporary immune suppression. The physical stress of high mileage, combined with travel, disrupted sleep, and race-week nerves, can all make you more vulnerable to catching a virus.
Getting ill before your race can be incredibly frustrating, especially after months of hard work and dedication. It can trigger panic, uncertainty, and endless second-guessing about what to do next: whether to rest or run, adjust your goals, or even pull out entirely.
To help you make smart, confident decisions, we’ve gathered expert insight from health professionals and running coaches on how to respond if illness strikes before race day, and what you can do to recover fast and protect your race.
Why Do You Get Ill Before Your Race?
David Nieman, a researcher and professor in exercise physiology, explains this through his “open window theory.” (Related: David Nieman: Ibuprofen and Running, Negative Effects and Substitutes).3loveas. (2019, November 26). Dr. David C. Nieman, DrPH, FACSM. Dr. David C. Nieman, DrPH, FACSM. https://ncrc.appstate.edu/directory/dr-david-c-nieman-drph-facsm
In Nieman’s research, he found that runners commonly get sick during tapering and after a marathon, within an ‘open window’ of 3-72 hours, during which the immune system is suppressed.
Nieman explains that moderate exercise prompts immune cells to circulate at a greater rate than usual, which gives them a better chance of encountering harmful germs and protecting you.
However, when you rigorously train, such as through long runs, your exhausted muscles need fuel to repair. As a result, the immune system is overworked and has a lot to do, making it ‘too confused’ to perform its jobs well.
Other factors, such as mental stress, poor sleep, and diet, can also impair immune function. So, if your long runs are not paired with extra food and extra rest, you increase your risk of getting sick.
First-time marathon runners with a lower fitness level may be more vulnerable to these effects.
Can You Run A Marathon If You’re Sick?
You can still run a marathon while sick if the illness is not severe enough to prevent you from doing so.
Many runners, including running coach Kaila Morgante, say they feel better when they go for a run.4Instagram. (n.d.). Www.instagram.com. Retrieved April 16, 2024, from https://www.instagram.com/bodkick/?hl=en
“I just want to go outside and shake it out,” she says. “But a run can either boost our immune system or compromise it.”
…So, where is the line?
Thomas Eichner, professor of medicine, came up with the ‘neck check’ to help runners decipher when it is safe to try a run when ill.5Eichner, E. R. (1993). Infection, Immunity, and Exercise. The Physician and Sportsmedicine, 21(1), 125–135. https://doi.org/10.1080/00913847.1993.11710319
With the neck check, you can run your marathon (with caution) if you have only above-the-neck symptoms, such as a runny nose, sneezing, and a scratchy throat.
With Eichner’s neck check, if your symptoms are below the neck on the day of your marathon, you should not run.
Do not run your marathon if you are ill with a fever, difficulty breathing, muscle aches and strong body aches, diarrhea, swollen lymph nodes, extreme tiredness, vomiting, a very sore throat, or a hacking cough that produces phlegm in your throat.
If you have a pounding headache or you feel lousy even thinking about running, rest instead.
In the days ahead of your marathon, you can do a test run (short and easy) as a shake-out and see how you feel. If you feel worse, you may need to push back your race date.
“Why go against Mother Nature?” Eichner told the LA Times. “It’s foolhardy to do a workout when your system is calling for rest,” adding that doing so puts a runner at risk for a more serious infection.6Krucoff, C. (1998, December 28). A Little Exercise May Help That Head Cold. Los Angeles Times. https://www.latimes.com/archives/la-xpm-1998-dec-28-he-58196-story.html
Related: Here Are The 11 Worst Things To Do Before A Race
Can You Run With A Cold?
Yes, if your cold symptoms are localized to your head without a cough, you can still run your marathon with a cold.
The American College of Sports Medicine has said that exercising moderately with a head cold is “probably acceptable” and perhaps even beneficial.7Mazzeo, R. (n.d.). ACSM FIT SOCIETY ® PAGE Inflammation, Disease and Exercise. Retrieved April 16, 2024, from https://www.acsm.org/docs/default-source/files-for-resource-library/fitsociey_0616.pdf?sfvrsn=1fa0c050_6
However, running a marathon is not moderate. Therefore, you should still proceed with caution.
Related: Running with a Cold: Should You Do It?
It’s important to note that Nieman’s research also suggests moderate exercise (roughly less than 60 miles per week, for less than 60 minutes) boosts immunity and helps prevent colds.
So… yes, running does make us healthier. But peak marathon training can take a toll.
What To Do If You Get Sick Before Your Race
There are several actions you can take to help you beat your illness before arriving at the start line on race day.
Note: All these tips are helpful for runners tapering for a full marathon and crucial for marathon runners who are ill in the days leading up to their marathon. They also apply to half-marathon runners.
#1: Eat Well and Prioritize Immune-Supportive Nutrition
When you’re fighting off an illness in the days leading up to your race, your nutrition becomes one of your most powerful recovery tools. A balanced, nutrient-dense diet supports your immune system, helps your body repair, and gives you the best chance to bounce back quickly.
Focus on whole, minimally processed foods that are rich in vitamins, minerals, and antioxidants, all of which help reduce inflammation and combat the oxidative stress your immune system experiences when it’s working overtime.
Load your plate with a variety of colorful fruits and vegetables, such as red peppers, oranges, leafy greens, and berries, to get a mix of antioxidants, vitamins, and minerals that support your immune system’s recovery and help combat inflammation.
In addition to plenty of produce, make sure you’re also eating enough healthy carbohydrates to keep your energy stores up. Your body needs glycogen to fuel the immune response and maintain performance if you’re still training lightly.
Include lean proteins (like fish, eggs, beans, or tofu) to support tissue repair and immune cell production, and healthy fats (such as olive oil, nuts, and avocado) to help reduce inflammation.
And don’t forget hydration. Drink water consistently throughout the day and consider adding electrolyte drinks or herbal teas if you have a sore throat or are experiencing a mild fever and sweating.
If your appetite is low, opt for easy-to-digest options like smoothies, soups, and oatmeal packed with fruit, nut butter, or honey. The key is to fuel your body, even in smaller amounts, continually, so it has the necessary resources to heal and recover.
#2: Get Plenty Of Sleep
Aim for at least 8 hours each night, says Todd Buckingham, lead exercise physiologist at Mary Free Bed Rehabilitation Hospital.8Mary Free Bed Rehabilitation Hospital: Home. (n.d.). Mary Free Bed Rehabilitation Hospital. https://www.maryfreebed.com/
“Sleep is the most important performance and recovery tool in your arsenal”, adding that deep sleep is when our bodies repair themselves.9Milewski, M. D., Skaggs, D. L., Bishop, G. A., Pace, J. L., Ibrahim, D. A., Wren, T. A. L., & Barzdukas, A. (2014). Chronic lack of sleep is associated with increased sports injuries in adolescent athletes. Journal of Pediatric Orthopedics, 34(2), 129–133. https://doi.org/10.1097/BPO.0000000000000151
If you’re unable to get 8 hours a night, try to get short naps no longer than 30 minutes before 3 p.m. These can also aid your body in the recovery process.
#3: Take A Hot Shower
“A warm shower can help clear congestion and cause your muscles to relax, aiding in the recovery process,” adds Buckingham.
“A shower can be very soothing. And the heat will cause blood vessels in your sinus cavity and lungs to dilate, which will cause you to feel less congested,” he says.
#4: Drink Lots Of Fluids
Staying hydrated helps your immune system work optimally by aiding the transport of oxygen to your body cells. Liquids can also help your body remove toxins that negatively impact your immune system.
And, don’t stick to just water, adds Buckingham.
“If you drink only water, it could dilute blood sodium levels. Chicken noodle soup is great for consuming some extra sodium when you’re not feeling well. There’s a reason your mom made it for you when you were sick as a kid!”
#5: Take A Probiotic
Research shows that seventy percent of your immune system lives in your gut. This is because your gut microbes help determine inflammation and the level of impairment to your immune system.10Cohen, S. (2021, March 19). Want to boost immunity? Look to the gut. Https://Connect.uclahealth.org/. https://connect.uclahealth.org/2021/03/19/want-to-boost-immunity-look-to-the-gut/
To keep your gut healthy, eat plenty of plants and seeds rich in fiber and antioxidants (as mentioned above), incorporate healthy fats, yogurt, sauerkraut, and take a probiotic supplement.
These actions will help keep your gut full of the right microbes, which in turn help keep your immune system functioning at its best.
#6: Go For A Walk When You Feel Up To It
As noted, exercise is good for your immune system. So, when you feel stronger, do some very light exercise, like go for a walk or an easy bike ride.
“Light physical activity can help you recover from an illness faster. Increasing blood flow will help transport white blood cells and nutrients to and remove waste products from the area,” adds Buckingham.
This walk will also help you assess if you are ready for a run yet.
Related: Should You Run Before a Race? Shakeout Runs Explained
#7: Limit Your Time Around Others Who Are Sick
You are still in the danger zone of getting sick after your endurance run, so be sure to limit your exposure to people, especially those who are ill, says Ethan Lahav, a certified running coach.
“If you can’t avoid being around sick people, try to wash your hands often.”
Keep up your rest, hydration, and healthy diet after the marathon to help you heal from your illness and recover from the marathon.
Related: How to Start Running Again After a Break
5 Steps To Get Healthy Before Your Race
If you get sick in the days leading up to your marathon, don’t panic; recovery is still possible.
The key is to listen to your body, prioritize rest, and gradually rebuild your energy, rather than rushing back into training. Here’s a step-by-step guide to help you assess whether you’re ready to toe the line on race day.
Step 1: Rest
Sleep and rest as much as your body needs. This is non-negotiable. When your immune system is fighting an illness, the recovery process requires significant energy, energy you’d normally spend on training.
Cancel workouts, stay warm, and focus on quality sleep and nutrition. Even a single extra night of solid rest can make a difference.
Step 2: Wait, Then Walk
Once you start feeling better, don’t jump straight back into running.
Allow your body at least one full day without symptoms before testing any activity. Then, go for an easy walk. “This will gently help your body recover from the illness and avoid stressing yourself out from running,” says Lahav.
A 15–30 minute walk should feel comfortable and leave you feeling refreshed, not fatigued or dizzy.
Step 3: Try A Short, Easy Test Run
If the walk feels fine and you remain symptom-free, the next step is a short, easy jog, no more than 15 minutes at a very relaxed pace.
Skip your scheduled workout plan entirely and focus on how you feel. If you experience fatigue, coughing, chest tightness, dizziness, or an elevated heart rate, stop immediately and rest for one to two days before reassessing.
Step 4: Go For A Short Run
If the test jog goes smoothly, you can attempt a slightly longer easy run the next day, around 20–30 minutes at a conversational pace.
“This will help aid your recovery and make you feel more confident about race day,” says Lahav. If you can complete this run feeling strong and recover normally afterward, that’s a good sign you may be ready to race.
However, if this effort leaves you exhausted or your symptoms return, it’s best not to go through with your marathon and prioritize your health.
Step 5: Prioritize Recovery Habits: Sleep, Eat, And Hydrate
In the final days leading up to your race, make recovery your full-time job. Eat well-balanced meals that are rich in carbohydrates, protein, and antioxidants to replenish your energy stores and support your immune system.
Stay hydrated with water and electrolytes, and aim for at least 7–9 hours of sleep each night. Reducing life stress and cutting out alcohol can also speed up recovery.
If you’re still unsure whether you’re ready to run, follow the “neck rule”: mild symptoms above the neck (like a runny nose or sore throat) usually mean you can attempt light running, but symptoms below the neck (like chest congestion, fever, or body aches) mean you should continue resting.
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