Determination of the effects of anaerobic threshold and respiratory compensation point parameters on pulmonary gas exchange dynamcis during exercise

Determination of the Effects of Anaerobic Threshold and Respiratory Compensation Point Parameters on Pulmonary Gas Exchange Dynamcis During Exercise The incremental exercise test is widely used in the determination of aerobic fitness levels. Anaerobic threshold (AT), which describes the metabolic transition point from aerobic to anaerobic and respiratory compensation point (RCP, which describes the onset of exercise hyperventilation are two important criteria's used to evaluate subjects systems functions, including ventilation (VE), O2 uptake (VO2) and CO2 output (VCO2). The relationships between VE/VO2 and VE/VCO2 during an incremental exercise test provide prognostic values regarding ventilation, perfusion relationship and ventilatory efficiency. In the present study, we comparatively examined the relationships between VE, VO2 and VE, VCO2 during an incremental exercise and also constant load exercise test regarding the obtain optimal ventilatory efficiency. Total of 11 male subjects performed an incremental exercise test (15 W/min) using an electromagnetically braked cycle ergometer to obtain AT, RCP and maximal exercise capacity. Then, each subjects performed 3 constant load exercise test: work load corresponded to 25% below AT (W<%25AT), at the AT (WAT) and at the RCP (WRCP). During exercise, ventilatory and pulmonary gas exchange variables measured breath-by-breath using metabolic gas analyser. AT estimated using V-slope method. During an incremental exercise, the relationships between VE/VO2 (26.2±0.9) and VE/VCO2 (25.7±0.8) are found to be lowest at the AT. In constant load exercise tests, VE/VO226.4±0.7 (W<%25AT) 29.1±0.9 (WAT ) 30.8±1.2 (WRCP) and VE/VCO2 were found to be systematically higher 27.3±0.5 (W<%25AT) 29.2±0.8 (WAT) 31.8±1.2 (WRCP). However, the lowest values of VE/VO2 (21.5±0.7, 23.3±0.9 and 22.2±1.0) and VE/VCO2 (25.1±0.5, 25.0±0.5 and25.4±0.7) observed in first 4 minutes of constant load exercise test were similar with the observed in incremental exercise test. As a result, we have found that lowest values of VE/VCO2 and VE/VO2 can be obtained easily in constant load exercise test without reaching maximal effort. Key words: Anaerobic Threshold, Respiratory Compensation Point, Aerobic Fitness, Exercise Test