Abstract

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.

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