What to Do if You Get Sick While Training for a Marathon

An expert coach explains the ins and outs of dealing with an illness during marathon training

It’s not uncommon for runners to get sick or injured while training for a marathon.

This, says Marty Beene, a Level 2 USA Track & Field  certified coach and creator of Be the Runner, is because “our bodies' resources for immunity against viruses are shared by our bodies' attempts to adapt to training stimuli.”

According to Beene, this means runners should actually be prepared with a back-up plan for what to when and not if they get sick.

He noted that while he’s had plenty of anecdotal experience with this situation through coaching clients and his own running career, he doesn’t have any medical training, so his advice comes exclusively from a coaching perspective.

How can you determine how much rest you’ll need and when it’s OK to start running again?
Beene says that when you’re recovering from an illness, by general rule of thumb you can start running again if you don’t have a fever and you’re not coughing.

Some experts put it this way: symptoms from the neck up are OK; symptoms from the neck down are not. And if you’re just dealing with a stuffed-up nose, Beene says running may actually help to alleviate your symptoms because adrenaline is an antihistamine, which may loosen up you nasal passages.

“It’s probably OK to start training again once your fever and cough are gone, although you may have to experiment with what ‘my cough is gone’ really means,” Beene said. “In my experience, a cough might hang on for weeks, but not get any worse with training.”

That said, Beene pointed out that the most important factor to base your decision on is simply how you feel.

“If your body just feels dead, then it's telling you it's not ready for training,” he added.

Should you be worried about your performance?
“In general, most common colds last about a week, give or take a few days, while stronger cold-like illnesses like the flu or bronchitis could last two or more weeks,” Beene said. “This is important to know because getting sick while training can destroy your confidence, but it doesn't necessarily have to.”

He continued, “If you catch a cold and decide not to train for up to a week, it's unlikely that missing, say, five or six training runs will hurt you that much if your training period spans 12,16 or 20 weeks. But if you get the flu and end up taking two weeks or more off of running, you can expect that to have a more substantial impact on your goals.”

Where in your training plan you should pick up when you’re ready to run again?
“The issue of where to pick up your training when you start running again is tricky,” Beene said. “If you've only missed a few days, there's no reason to think you wouldn't be able to jump right back in with whatever you had planned. But any longer than that, or if your symptoms were severe—even if short-lived— then you should make adjustments.”

One thing you can try, he said, is to continue with your planned training volume, while slightly reducing the intensity.

“Similarly, if your training intensity is relatively low anyway, then reducing the training volume would be wise,” Beene added. “I would recommend trying about a 20 percent reduction initially—so a 40-mile week would be reduced to 32; a 15-mile run would be reduced to 12. Knowing that these changes will have different effects on different individuals, that 20 percent reduction could really vary from as little as 10 percent to as much as 50 percent.”

Beene also highly suggests keeping a detailed log of your training, including how you’re feeling, so that you can have a good idea of what to do next time.

What should you do while you’re resting?
Beene said the key to a successful return to training is making sure to take care of yourself while you’re sick.

“You definitely don't want to do anything intense or very long,” he said. “The best exercise to fit your needs when you're sick is walking. Walking can be done at an intensity low enough that it won't interfere with your recovery. Or, if you're feeling sort of OK, you can walk faster or a little farther.”

He explained that in most cases, a 30-minute walk on days when you’re not able to run should be enough.

“The main reason walking works as an activity to do when you can't train is simply that you are continuing to use your legs,” Beene said. “If you use your legs to do something similar to running, your body will sense that the training adaptations you've made are still needed.”

Additional Factors to Consider:
“Another factor is when the illness occurs in your training cycle. If it's early enough, you could target about two or three weeks to get completely back onto your original plan,” Beene said.

He continued, “So your first week might be 20 percent less running; the second week could be 10 percent less; then by the third week, you could be back on track. If your illness is relatively close to your goal race, there might not be much you can do to get back on schedule.”

Ultimately, Beene said the most important thing to remember when you return to training is that you need to be flexible. 

“Even with the same individual, the effects of different viruses could be vastly different, so a return to training might be done in very different ways,” he said.

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