The effects of two weeks high-intensity interval training on fasting glucose, glucose tolerance and insulin resistance in adolescent boys; A pilot study

Abstract

Background This study examined whether improvements in fasting and postprandial [insulin], [glucose] and aerobic fitness are possible after two weeks of high-intensity interval training (HIIT) in adolescent boys. Methods Seven boys (14.3 ± 0.3 y) completed 6 sessions of HIIT over two weeks. Homeostatic model assessment of insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), fasting glucose:insulin ratio (FGIR) and blood [glucose] and [insulin] responses to a Mixed Meal Tolerance Test (MMTT) were assessed before (PRE), and 20 h and 70 h after (POST) the final HIIT session. Maximal oxygen uptake (VO2 max) was assesed PRE and 70 h POST. Results Compared to PRE, two weeks of HIIT had no effect on fasting plasma [glucose] or [insulin] or HOMA-IR at 20 h and 70 h POST. However, a strong negative correlation was observed between PRE training HOMA-IR, QUICKI and FGIR, and change in HOMA-IR, FGIR and QUICKI at 20 h POST (r =-0.96, 0.969 and 0.826 for HOMA-IR, QUICKI and FGIR respectively all P<0.05). Plasma [insulin] and [glucose] area under the curve in the postprandial period following the MMTT were unchanged 20 h and 70 h POST compared to PRE. Conclusion Two weeks of HIIT did not elicit improvements to fasting or postprandial glucose or insulin health outcomes or aerobic fitness in a group of adolescent boys. Interventions of this type may, however, be effective in adolescents with raised baseline IR.