Dial back your training to look after your immune system in a COVID-19 world.

We are in unusual times, COVID-19 is impacting every part of our lives. For most people, COVID-19 is not a serious illness. Almost everyone will recover, many will not even show symptoms after they contract the disease. The great news is that fit athletes are less at risk. There is plenty of medical evidence to suggest that an amount of moderate training helps build a strong immune system

The compelling link between physical activity and the body’s defense system is a scientific paper by David C.NiemanaLaurel M.Wentzb that concludes:

  • Acute exercise is an immune system adjuvant that improves defense activity and metabolic health.
  • Data support a clear inverse relationship between moderate exercise training and illness risk.
  • Exercise training has an anti-inflammatory influence mediated through multiple pathways

So this is great news for athletes, but there is a flip side:

Illness risk is increased in athletes during periods of intensified training and competition

David C.NiemanaLaurel M.Wentzb

There is a great deal of research that deals with the fact that hard training and racing can suppress you immune system. This piece of information may come as a surprise.

Training hard may make you ill.

Think about it, how often has your passion for your sport led to you making bad choices by training when ill. Does your obsession mean that you are not prepared to miss a training sessions. Is your obsession making you ill.

Unfortunately, as with most things in science, there is always a counterpoint. You can pick up one published article and it seems compelling. Pick up another and you will find a different scientist saying a different thing. This New York Times article offers a counterpoint to the previously mentioned research.

Here is a great video-blog from Dr Ben Lynch on making sensible choices as an athlete in the face of the threat from COVID-19. Ben cites the same paper I reference above.

So what to do? Hard racing and training can suppress your immune system. Maybe yes. Maybe no. I think we can safely say moderate training enhances the immune system. Hard training may or may not put at risk of suppressing your immune system. However in the face of COVID-19 why take the risk.

You could play it safe and choose to shift your training to lower intensity moderate training ‘base training’. However be aware of duration and evironment. Hours of base training, outdoors, in cold weather could have a similar effect as short hard intense training. If we are talking Training Stress Score (TSS) I would aim of a score between 60 and 80 for any session focused on Zone 1/Zone 2 power and/or heart rate.


Here is my take away from this information:

  • Moderate training enhances your immune system, keep doing it.
  • During the COVID-19 outbreak, consider dialing back your training to enhance and protect your immune system.
  • Be aware that hard training and racing can suppress your immune system and increase your risk of complications from COVID-19.
  • The jury might be out on the impact of hard training on your immune system, but you need to weigh up the evidence and make a choice.
  • However, if you are feeling unwell, under the weather seriously consider dialing back your training or stopping completely while you recover.
  • During the COVID-19 outbreak shift your training towards lower intensity moderate training. Now is a good time for all that base work you have been missing. However consider duration and overall load when making your choices.


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