Effect of 6 weeks of very low-volume high-intensity interval training on oral glucose-stimulated incretin hormone response

Introduction: Decreased fasting and oral glucose-stimulated incretin hormone concentrations following moderate-intensity continuous endurance training interventions have been reported in glucose-tolerant people, however results are conflicting. The effect of more time-efficient, very low-volume, high-intensity interval training (HIT) on circulating incretin hormone levels has never been studied. Materials and methods: Ten sedentary and overweight-to-obese participants (4 women and 6 men; age 43 +/- 6 years (mean +/- SD); BMI 30.2 +/- 3.2 kg.m(-2); HbA1c 35 +/- 5.1 mmol.mol(-1) (5.3 +/- 0.3%); VO(2)max 30 +/- 5 ml.min(-1).kg(-1)) from the Copenhagen cohort of the METAPREDICT trial underwent 6 weeks of supervised low-volume HIT (3 sessions per week: 7 x 1 min at similar to 100% VO(2)max separated by 1 min of active recovery). We measured glucose, insulin, C-peptide, glucagon, GLP-1 and GIP concentrations during a frequently sampled 75 g oral glucose tolerance test as well as VO(2)max and body composition before and after the intervention. Results: Training compliance was 100%. Relative VO(2)max improved after the intervention (median 2.69 ml.min(-1).kg(-1), IQR [0.43; 3.14], p = 0.037) while there were no significant effects on body weight and composition. No significant effects on oral glucose-stimulated glucose and hormone responses or estimates of insulin sensitivity and beta-cell function were observed. Conclusion: Low-volume HIT improved aerobic fitness, but neither affected glucose tolerance nor oral glucose-stimulated incretin hormone responses in sedentary and overweight-to-obese people.