Coach, I am sick today with flu, should I train?

It is cold and flu season (and I didn’t even mention coronavirus 😉 )

But it’s tricky to know whether to exercise and train, particularly tricky as even doctors don’t agree themselves! For example 90% of doctors in Poland say “stay home” with a cold but 90% of doctors in Norway say “Go Out!” when you have a cold (ref).

For the record when I say sick, I mean with any of: colds; coughs; early/mild influenza; sinusitis; tonsillitis; throat infections; middle ear infections

So here is my answer:


you don’t have to train today…..

If you have been training hard and don’t feel you can train today, have a few days off until you feel better, then come back soon, building up slowly. You will likely be back on track in no time. Especially do not train if you feel you are deteriorating, you feel unsafe, you have cardiovascular symptoms (eg palpitations) or confusion or dehydration. That said , for years, I played football (soccer) when I had aches and pains and minor colds but I also knew those days when I couldn’t play, those were days I could not get to the pitch, or even out of bed because of severe flu!

However, if you feel *well*, but have a slightly off whoop score, mild temp (<99F <38 C ), slightly higher resting HR then you can do a light workout. In fact, you will probably feel worse if you do not. Similarly you do not need to wait until you are 100% well to restart. That’s because very rarely does mild-moderate exercise weaken the immune system or delay recovery (blog on this), in fact nearly all medical studies show that exercising early is one of the best forms of rehabilitation.

But Don’t forget, exercise usually promotes recovery.

Based upon research by Martin et al (ref) light or moderate exercise causes a subtle shift away from the production of pro-inflammatory cytokines IL-2 and IFN-γ and toward a by the secretion of anti-inflammatory proteins IL-4 and IL-10 response, enhancing recovery in cases where viral load is high. But sure, prolonged or high-intensity exercise according to some studies (1,10,19) *might* be detrimental to influenza recovery (29,30)



Only a couple of field studies have actually dared test this!




Results: Does a cold affect your ability to exercise?

To address that, the Dr Kaminsky recruited 24 men and 21 women ages 18 to 29 and of varying levels of fitness who agreed to be deliberately infected with a rhinovirus, which is responsible for about a third of all colds. Another group of 10 young men and women served as controls; they were not infected. The researchers reported that having a cold had no effect on either lung function or exercise capacity.


Results: Does exercising when you have a cold affect your recovery time?

Once again, Dr, Kaminsky and his colleagues infected volunteers with a rhinovirus. This time, the subjects were 34 young men and women who were randomly assigned to a group that would exercise with their colds and 16 others who were assigned to rest.

The investigators found no difference in the time it took to recover from the colds. But when the exercisers assessed their symptoms, Dr. Kaminsky said, “people said they felt O.K. and, in some cases, they actually felt better.”


What about Above-the-neck rule?

The above-the-neck rule says if your sickness is located above the neck, you should be safe to exercise and it might help

  • Earache Headache
  • Sore throat
  • Sinus pressure
  • Sneezing Stuffy or
  • runny nose


and below-the-neck symptoms?

But I actually think these are ok too…..I used to take ibuprofen and do a light workout and usually I found it worked!

  • Fever Chills
  • Fatigue Muscle or body aches
  • Coughing or chest tightness
  • Wheeze

But wait what about the “No-go” symptoms?

True, let’s not forget these, I would say these are

  • Diarrhea Vomiting
  • Dizziness
  • Visual problems
  • Confusion
  • Drowsiness

I wouldn’t advise exercise with any of those!

…but what specific activity should you do? I do advise you consider these instead…..

Activities to consider when you’re sick.

  • Walking (socially distanced)
  • Jogging
  • Swimming
  • Spin bike on your own
  • Light turbo training on your own
  • Qi gong
  • T’ai Chi
  • Yoga

Activities to avoid when you’re sick.

  • Heavy weight strength training
  • Long endurance training
  • High intensity interval training
  • Team sports
  • Social sports
  • Exercise in extreme temperatures

Other Specific Conditions

We consulted Evidence Based Sports Medicine (MacAuley&Best) which has a chapter on exercise with a fever or infection but they also discuss:

Myocarditis: they recommend 6 months off and then supervision by a cardiologist

Viral Hepatitis: Exercise is ok, but avoid competition and HIT

Infectious Monoucleosis (mono): be cautious with splenic enlargement


And finally what about immunosuppression (and what if I have COVID?!)

I cover that here:

So that’s it!

Basically, be guided by your body and/or your doctor and/or tests, be safe, but generally you can still push yourself a little and that usually aids recovery. Look at it like this…….you should always push yourself a bit but never to much…..but if you are stuck in bed, push yourself to the shower! If you are stuck on the couch, push yourself to do a walk, if you are able to walk, maybe push yourself to a short gym or spin session.

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