2009, Volume 1, Issue 1
Changes Related to Fatigue in Cardiorespiratory Response Sensitivity to Hypoxic and Hypercapnic Stimulation during Strenuous Physical Load
Viktor Mishchenko1, Andrzej Suchanowski2, Olena Lysenko3
1Jedrzej Sniadecki Academy of Physical Education and Sport in Gdansk
2Department of Physiology, Jedrzej Sniadecki Academy of Physical Education and Sport in Gdansk
3National University of Physical Education
Author for correspondence: Andrzej Suchanowski; Department of Physiology, Jedrzej Sniadecki Academy of Physical Education and Sport in Gdansk; email: vmishch[at]awf.gda.pl
Author for correspondence: Olena Lysenko; National University of Physical Education
Background: The aim was to study changes in the sensitivity of CRS responses of skilled athletes caused by fatigue during a strenuous physical load.
Material/Methods: Response sensitivity to hypoxic and hypercapnic stimuli was analyzed in a group of high performance rowers (n=12) aged 18-22 years during exercising on “Concept-II” rowing ergometer. Two types of loads were used: sustained intensive load at high oxygen consumption (78-83% of VO2max) and relatively easier load (49-62% of VO2max) performed within 5 minutes. The method of rebreathing was used to determine responses sensitivity to СО2.
Results: The results showed an increase in respiratory response sensitivity to hypoxia and a decrease in sensitivity to acidosis stimulus of respiration (СО2–Н+) at the end of a strenuous load in presence of fatigue. Ventilatory response to hypoxic stimulus increased reliably before the end of work. At high intensity of loads during increment hypercapnia even in highly trained athletes the inhibition of ventilatory response has been noted.
Conclusions: The data provide additional grounds for correction of fatigue by means of regulating the character and the intensity of physical loads in the process of endurance training. It has been shown that changes in sensitivity of CRS responses and other aspects of reactive features are of importance for special work capacity manifestations
Key words: fatigue, cardiorespiratory response, hypoxia, hypercapnia, training load