Aims/hypothesis: The influence of postprandial high intensity exercise on glycaemia was studied in patients with Type II diabetes mellitus.
Methods: Patients who were treated by diet only (n = 8) ate a standardised breakfast and 4 h later a standardised lunch. They were studied in the resting state (control day) and on another day (exercise day) when they did intermittent exercised at high intensity after breakfast) (4 bouts including 3 min at 56.5 +/- 3.9 % V.(O2) (max) (means +/- SEM), 4 min at 98.3 +/- 5.1 % V.(O2) (max) and 6 min of rest). Responses were calculated as areas under the plasma concentration curve (AUC) during 4 h after either breakfast or lunch.
Results: Breakfast-AUCs for glucose, insulin and C peptide were lower (p < 0.05) on the exercise day compared with the control day (glucose: 538 +/- 94 vs 733 +/- 64 mmol. l(-1). 240 min; insulin: 16 +/- 4 vs 22 +/- 3 pmol. ml(-1). 240 min; C peptide: 143 +/- 22 vs 203 +/- 29 pmol. ml(-1). 240 min). After breakfast glucose appearance was unaffected by exercise, whereas disappearance and clearance increased (p < 0.05). Muscle glycogen was diminished by exercise (p < 0.05). After lunch no differences were observed between experiments. Exercise-induced reductions in glucose, insulin and C peptide responses were similar (p > 0.05) in this study of intermittent, high intensity exercise and in a previous study of isocaloric but prolonged moderate (45 min at 53 +/- 2 % V.(O2) (max)) postprandial exercise.
Conclusion/interpretation: Postprandial high intensity exercise does not deteriorate glucose homeostasis but reduces both glucose concentrations and insulin secretion. The effect of exercise is related to energy expenditure rather than to peak exercise intensity. Finally, postprandial exercise does not influence glucose homeostasis during a subsequent main meal. [Diabetologia (1999) 42: 1282-1292]