In this study, we aimed to determine the exercise intensities eliciting the highest (FATmax) and the lowest (FATmin) fat oxidation rate in male cyclists and to compare these intensities with their individual aerobic (AeT) and anaerobic (AnT) thresholds, respectively. Twenty-two moderately trained male cyclists performed a 2-min stage graded exercise test until exhaustion using breath-by-breath gas analysis to determine maximal oxygen consumption (VO2max). The fat oxidation rate was calculated using a stoichiometric equation, with metabolic thresholds being determined by ventilatory gas analysis. In the present group of subjects, FATmax was found at a 21.34 ± 3.64 ml·kg-1·min-1 corresponding to 45.05 ± 7.68% VO2max. AeT occurred at an exercise intensity of 22.15 ± 4.84 ml·kg-1·min-1, matching 46.76 ± 10.24% VO2max. AnT and FATmin were located at intensities equivalent to 32.56 ± 5.52 ml·kg-1·min-1 and 32.30 ± 5.35 ml·kg-1·min-1 which corresponded to 68.74 ± 11.65 and 68.19 ± 11.29% VO2max, respectively. The correlation between FATmax and AeT was strong (r = 0.80, p < 0.05). No statistical difference was observed between FATmin and AnT (r = 0.99, p < 0.05). The strong relationship between observed indices can be used to provide a more tailored exercise approach.
Keywords: Exercise; metabolism; performance; testing.