What does the open window effect mean?

1. May 2018

Anyone who has accomplished a particularly hard training unit knows the feeling: you are tired, need sleep, and will possibly also suffer from sore muscles the next day. This condition also means hard work for our immune system: it needs to remove destroyed cells and repair and replace fine tears in the muscle tissue microstructure as well as worn tissue particles. 

At the same time, however, our immune system is also responsible for the fight against infectious agents. It is no wonder, then, that the body’s defences are restricted immediately after an intensive exertion. In this phase – which is technically known as "open window" – the body is more susceptible to pathogens and thus also infections. It depends on the type of exertion as to how long it takes until the immune system returns to normal. Basically, the following applies: the more intensive the sports activity, the greater the strain on the immune system. It can thus take several hours or even several days.

This temporary “hole” in the immune system does not necessarily mean that you will automatically fall ill, but it does mean that you should exercise particular caution to prevent an infection. In competitive sports, many colds break out this phase. The infections are usually limited to the upper respiratory tract and manifest themselves as a sore throat, coughing and sniffling. As an athlete, you can counter the risk with the following measures:

  • Change clothes immediately: Straight after training, change into dry and warm clothes and don’t stand around in the cold and wet.
  • Take a hot shower: Take a hot shower as quickly as possible, dry wet hair and possibly wear a hat.
  • Drink a lot: Recoup your fluid loss as quickly as possible.
  • Eat well: You should also recoup your energy loss as soon as possible by eating food with sufficient carbohydrates and protein. If this is not possible, then a recovery shake is a sensible alternative.
  • Get enough sleep: Make sure you get enough sleep. Sleep is an integral part of recovery.
  • Cut down on alcohol: It makes sense to abstain from alcohol. Alcohol prolongs the regeneration period.
  • Avoid outbreaks: Avoid large crowds of people on the bus, train, in shops, and discos etc. 
  • Sports break: Take a sufficiently long sports break before training intensively again. Even top athletes don’t do more than three intensive training units a week.

And if you're now getting a bit worried about training rigorously, then this is for you: exercise and sports generally strengthen the immune system and the body’s defence, so there is no reason not to push yourself to the limit now and again.