Measuring glucose during exercise testing is a simple and cost-effective way to assess physiological variables. Individual glucose threshold (IGT) is the lowest glucose value during an incremental exercise test and corresponds to the individual anaerobic threshold. The purpose of this study was to determine the kinetics of glucose during a cycling incremental exercise test, assess the possibility of determining IGT, and compare it with other lactate and ventilatory variables. Methods: The study included 27 young cyclists (mean age = 17.7; SD = 1.0 years and V̇O2max mean = 70.7; SD = 4.5 ml.kg.min-1), who performed an incremental exercise test starting at 100 W with an increase of 20 W/min until exhaustion. Blood lactate and glucose measurements were taken every 2 minutes, and ventilatory variables were monitored. The glucose kinetics during the test were analyzed, and individual glucose threshold (IGT) and other lactate and ventilatory variables were calculated. IGT was compared with other ventilatory and lactate thresholds. Results: The kinetics of glucose clearly showed a decrease in the initial stages and an increase in the final stages of the test. Glucose levels remained significantly elevated 5 minutes after the test, even during active recovery at 50 W. IGT was calculated at 305 (SD = 41) W, with a relative value of 75.2% of Wmax. IGT significantly differed from VT and Rise 1 mmol, while it corresponded to LT, OBLA, Dmax, RCP, and RQ1. Correlation analysis showed moderate positive correlations between variables and IGT (r = .43 - .68, p < .05). Conclusion: This study is the first of its kind on such a well-trained sample and adds to the existing literature with unique insight into comparison of IGT with other variables. IGT is a useful and affordable variable that can be used in the context of physiological testing. Further research is needed to better understand IGT and its application in elite sports.
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