An acute bout of 4 x 4-minute or 10 x 1-minute HIIT improves beta cell glucose sensitivity in post-menopausal females with type 2 diabetes: a secondary analysis.

Abstract

Aims/hypothesis: Improvements in glycemic control following acute exercise are typically attributed to improved post-exercise insulin sensitivity (IS) with comparatively little known about how acute exercise impacts beta cell function, especially in post-menopausal females. We determined how two high-intensity interval training (HIIT) protocols, matched for total estimated energy expenditure, impact beta cell function in post-menopausal females with type 2 diabetes. Methods: Thirteen post-menopausal females (70 ± 5 years; 12 ± 7 years since diagnosis, 80.9 ± 13.8 kg, 32.4 ± 5.6 kg*m²; HbA1c - 49.8 ± 10.3 mmol/mol [6.7 ± 1.0]) living with type 2 diabetes were included in this semi-randomized crossover trial. The trial involved an initial resting control condition followed by two HIIT conditions [4 X 4-minute HIIT (HIIT4) and 10 X 1-minute HIIT (HIIT10)] completed in a randomized order 2-4 days apart. Beta cell function (glucose sensitivity) and insulin sensitivity were determined from a 2 h mixed-meal tolerance test performed 2 hours after rest or HIIT. Results: Both HIIT4 and HIIT 10 significantly improved beta cell glucose sensitivity compared to control (15 pmol*min^-1*m^-2[mmol/L]^-1, [95% CI 6, 23]; p= 0.002 and 16 pmol*min^-1*m^-2[mmol/L]^-1, [95% CI 7, 25]; p= 0.002, respectively), with no difference between HIIT protocols (1 [-8, 10], P = 0.79). There were no significant differences in IS metrics (Matsuda index, OGIS, Stumvoli, and QUICKI) between the conditions. Conclusions/interpretation: An acute bout of 4 X 4-minute or 10 X 1-minute HIIT improves beta cell glucose sensitivity in post-menopausal females living with type 2 diabetes.