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 × 1 min at ∼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 β-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. Highlights Ten sedentary, overweight-to-obese, glucose-tolerant participants underwent 6 weeks of supervised, very low-volume HIT.Aerobic fitness improved.Fasting and oral glucose-stimulated incretin hormone concentrations were not affected.