Cardiorespiratory responses of swimmers to hypoxia and hypercapnia

Introduction. Physiological mechanisms of respiratory and cardiovascular systems interaction of a humans body gas exchange function with participation of chemoreceptors have been insufficiently studied. Herewith, the authors suppose that regular specific practice in certain kinds of sport forms definite chemoreactive properties of the cardiorespiratory system. The aim of the work was to study the chemoreactive characteristics of the cardiorespiratory system, height-weight data, and gas exchange values in swimmers of different sports qualification. Materials and Methods. Two groups of swimmers were examined: 9 athletes of a high rank (Candidate for Master of Sports, Master of Sport and Master of Sports, International Class) and 10 athletes of low rank (First, Second and Third-class Sportsmen). The cardiorespiratory system response to inhalation of gas mixture changes in hypercapnic and hypoxic tests were investigated during rest. Results. It is shown that highly qualified swimmers have stronger interrelations between body height and weight, and lower levels of gas exchange and lung ventilation. The continuous intensive swimming training, connected with volitional breathing control, can lead to elevation of diastolic arterial pressure. Swimmers are characterized by the ability to sustain the blood hemoglobin oxygenation at higher level in hypoxia, when the heart rate responses decrease in high quality swimmers. Conclusions. There is a reciprocal supplementing interaction mechanism of separate cardiorespiratory parts (respiration and heart) responses to changes of blood gas composition. Herewith, total chemoreactivity of cardiorespiratory system can vary with the kind of sports training, particularly decrease in swimming training. Keywords