Engaging in regular, moderate physical activity (30 to 60 minutes per day) strengthens our natural defenses by optimizing the circulation of protective cells and limiting stress hormones. Conversely, effort that is too intense or prolonged may temporarily weaken the body through a mechanism known as the 'open window.'

noli's read

The idea that regular, moderate physical activity supports our natural defenses is well-validated. Observational studies conducted by researcher David Nieman associate a daily routine of moderate exercise with a significant reduction in the frequency of minor seasonal ailments. By accelerating the body's circulation, exercise effectively helps protective cells better patrol the body. However, the 'open window' hypothesis—which posits that intense effort temporarily weakens our immunity—is now strongly contested. In an extensive research review published in 2018, researchers John P. Campbell and James E. Turner show that the post-exercise drop in protective cells in the blood is not a weakening, but a redistribution of these cells toward sensitive tissues to enhance our surveillance. Finally, the analogy between the increase in body temperature during exercise and fever as a means to slow down viruses lacks direct scientific evidence in humans.

the sources

1. 1Campbell JP, Turner JE 2018