In sedentary children, the immune system is weakened. Walking in the fresh air is good not only because the child "puffs up" the appetite. Being on the street, where there are many bacteria, the immune system absorbs them and starts producing antibodies. Thus, it is tempered.
A child who has been locked up at home for a long time, got into a kindergarten or school, did not adapt to a large number of viruses, he is more often sick and more difficult to bear various diseases. The walk should last at least 2 hours a day.