The autonomic nervous system is the part of the human body that is responsible for its survival. By acting through the senses that send information from the outside to the brain, it makes the processed information be sent to other parts of the body. The autonomic nervous system can also act independently of the information that the brain sends further into the body. That is, it stimulates the body's reaction even before the person becomes aware of it. Children, especially preschoolers, are in their formative years, which is why their reactions are mostly instinctive and often learned. Learned reactions child adopted in his primary and secondary environment. In kindergartens, but also in the family, children are primarily taught socially acceptable behavior and are guided to their overall development. Through various activities, children's skills and abilities are developed. Everything that children are taught does not have to be in line with the functioning of the child's body, although he will try to absorb most of the external stimuli. Imbalance of the autonomic nervous system, i.e. a chronic state of disharmony and anxiety in children is the cause of later somatic and psychosomatic disorders. Man is not only a social being, but first a biological being, so his development and action must be observed from the biological and then the social context. Children being outdoors stimulates all their senses and encourages their integration. Man's "biogrammar" corresponds to fresh air, natural noises and various forms of movement. By staying in nature, the human body feels stimulated, safe and satisfied. Its origin is manifested in nature. An online questionnaire was conducted among kindergarten teachers in the Republic of Croatia (n = 316) to assess the importance of children being outdoors and their attitudes on it. The results of the research showed that children being outdoors is equally important to being indoors and that fresh air is suitable for the development of various skills in children.