Reference values of DB, OT, VM parameters were determined in young people at the age of 15-19 years. The most sensitive test for ascertainment of developmental changes was test of deep breathing. I/E was increased in the 19-year-old group compared with 15-year-old group indicating an increase of vagal activity. Girls had decreased some parameters of deep breathing and orthostatic test compared with boys in the same group (15-19 years).