Are You Too Sick To Run?

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Are you too sick to run? find out when you should rest and when it's okay to run Are You Too Sick To Run?

Runners – and athletes in general – have a tendency to just sort of power through all sorts of pain and discomfort. And, while this mental toughness and tenacity can be a very useful trait, it can also go too far. Sometimes, runners ignore signs from their body that it’s time to take a break and train when they should be home resting.

With cold and flu season coming up quickly, this topic is worth exploring. When are you too sick to run? What symptoms should you look out for when making your decision?

The Basic Guideline

In general, experts presented with this question will usually cite the “above the neck rule,” which states that as long as your symptoms are above the neck, you’re good to go. Essentially, this means that congestion in your nose and sinuses shouldn’t stop you from working out that day.

According to the same principle, though, any symptom occurring below the neck – in your chest and stomach – should keep you home. This includes congestion or a cough in your chest or any digestive upset resulting from a virus.

Now, it’s important to remember that this is just a basic guideline and doesn’t strictly apply in all situations. For example, a fever is – technically – an “above the neck” symptom that should nonetheless trigger a rest day. Whole-body aches, which really fall outside of these borders, are also a sign that you should not exercise.

Needed Adjustments

Even if your illness is respecting the borders of your neck, you will likely need to make some changes to your routine. Primarily, this will likely involve reducing the frequency, intensity and duration of your runs. After all, if congestion is making it difficult for you to breath, you aren’t going to have a particularly successful workout anyway.

Granted, this can be a frustrating development if it slows down your training progress. It’s important, though, to keep things in their proper perspective. First, viruses typically go away with a week if your body is allowed to handle them properly. So, that temporary decrease in your training will be very short-lived.


More importantly, pushing yourself to exercise at your normal intensity could make matters worse and limit your ability to recover. Which neatly sets up the next key factor to consider: the immunity sweet-spot.

Everything In Moderation

The need for balance and moderation is often cited in regards to many aspect of health and fitness. And, the issue of exercising while sick is no different.  According to researchers, there is a clearly defined J-shaped curve in immune function when exercise is involved. But what, exactly, does that even mean?

The situation is well illustrated by a pair of mice studies published in the journal Brain, Behavior and Immunity in 2008. In one of these studies, mice were (somewhat cruelly) infected with a particularly deadly virus. Then, the mice were separated into three groups that either sat around doing nothing, jogged for 20 to 30 minutes or ran for two and a half hours. This routine was repeated for three days, until the animals started to display symptoms. More than half of the sedentary mice died. A massive 70 percent of the high-intensity exercise group suffered the same fate, suggesting that exercise actually suppressed the animals’ immune response.

The real surprise, however, came when the researchers looked at the moderate exercise group. Only 12 percent of these mice died from the virus.

Similar findings – without all the death – have been replicated in humans, as well. So, what does this all mean? Essentially, moderate exercise can improve your body’s immune response and help you fight off any viral invaders. Pushing yourself too hard for too long, though, can have the opposite effect and actually reduce the efficacy of your immune system. Remember, the mice that went through a strenuous workout actually faired worse than those that didn’t do anything at all.

And this fact likely isn’t all that surprising to the more experienced marathon runners out there. Often, these athletes learn to expect a cold within a few days of finishing an event.

The Takeaway

What, then, should you do if you’re feeling sick? Take stock of your symptoms. If you’re just experiencing some congestion in your nose and throat, you can probably head out for a run. When those symptoms drop below your neck or include a fever, though, stay home and rest.

Even if you pass the “above the neck” test, though, reduce the overall intensity of your workout so that it falls in the moderate category. Basically, this should put your perceived exertion around a six on a scale of one to ten. Granted, you might be low on energy and feel like doing anything but going for a run. A properly balanced workout, though, could actually give your immune system a boost toward getting over the virus.


  1. Edward R. Laskowski, M.D. , Is it OK to exercise if I have a cold?, Blog
  2. Murphy EA1, Davis JM, Carmichael MD, Gangemi JD, Ghaffar A, Mayer EP., Exercise stress increases susceptibility to influenza infection, Journal