FIT for LIFE Knowledge Base Recovery Winter

What is the “Open Window” phenomenon?

Exercise is healthy and strengthens the body. But in the short term, the immune system is weakened after a hard workout and needs to recover. During this phase, the ‘window’ will be open and the immune system’s defences limited. That’s something to keep in mind.

Anyone who has completed a particularly hard workout knows the satisfying feeling of deep fatigue. The mind can now recover, but the body continues to work and prepare itself for new activities. The immune system has to remove destroyed cells, repair and replace fine tears in the microstructures of the muscle tissue as well as worn-out tissue particles.

The window is open for a short time

During this phase, the immune system’s defenses are restricted – what is known in technical jargon as an “open window.” As long as “the window” is open, we are more susceptible to pathogens and thus to infections, currently a big issue anyway due to Covid and the time of year.

How long the “open window” lasts varies and depends on the type of stress. The sensitive phase can last only a few hours, but also several days. In general, the more intense and exhausting the sporting activity, the greater the challenge to the immune system.

Caution is called for in winter

As an athlete, you should pay sufficient attention to the “open window” (e.g. after an intensive city run in cold weather) and take special care to prevent infection as far as possible. It is no coincidence that many colds in competitive sports occur exactly in this phase. The following precautions will help after intense training or competition, so that the window can be closed again without consequences:

  • Change clothes immediately: Immediately put on dry and warm clothes and don’t stand around in the cold or wet
  • Take a hot shower: Take a hot shower as soon as possible, dry wet hair and put on a hat if necessary.
  • Drink plenty of fluids: replenish fluid loss as quickly as possible.
  • Eat well: As soon as possible, compensate for energy loss with food and sufficient carbohydrates and proteins.
  • Make sure you get enough sleep: Sleep is an important component of a good recovery.
  • Avoid alcohol: Alcohol prolongs recovery.
  • Avoid hot spots: Avoid large crowds on the bus, train, shopping stores, etc.
  • Take a break from sports: Allow for a sufficiently long break from sports before resuming intense training. Even top athletes do not do more than three intense workouts in a week.


Text from FITforLIFE – This blog post was provided to us by the Swiss magazine FIT for LIFE. If you want to read regularly informative knowledge articles in the field of running and endurance sports, click here.