Purpose: To investigate a blood glucose profile and turn
point during incremental exercise.
Methods: Thirty-three national and international-level swimmers undertook a 7 × 200 m discontinuous, incremental, training set on a six-minute turnaround. Subjects were asked to be two hours post-absorptive, which resulted in a mean blood glucose level of 5.5 ± 0.57 mmol/l. After each 200 m-swim blood lactate, blood glucose, and heart rate were taken and values
plotted against the velocity of each swim. A Glucose turn point (Gt) was observed and defined in this study as an upward deflection after which blood glucose continues to rise. The Dmax, Borch, and LogLog methods were used to calculate Anaerobic Threshold (AnT).
Results: Significant differences were observed between
Gt and all three methods of AnT for swim pace, heart rate,
blood glucose, and lactate (P < 0.005).
Conclusions: Blood glucose profiles and the identification
of Gt are not linked to AnT. Gt may be an effective tool for
the observation of exercise intensity that is independent of
the mechanisms underlying AnT
