The effect of a single bout of high intensity intermittent exercise on glucose tolerance in non-diabetic older adults

Our aim was to investigate the acute effects of a single bout of high intensity intermittent training (HIIT) on glucose tolerance and other physiological and metabolic markers in non-diabetic older adults. Fourteen healthy older adults (age, 64 ± 2 y; BMI, 25.7 ± 2.8 kg·m^-2) performed two acute exercise trials: continuous moderate intensity exercise (MOD) and HIIT, with the response to an oral glucose tolerance test (OGTT) determined <24 hours after. Inflammatory, haematological, and lipid parameters were also assessed the day after each trial. There was an effect of the trials on the insulin response to an OGTT (P=0.047), but not the glucose response. Following an acute bout of HIIT, insulin concentration during an OGTT was elevated at 60 min compared to the control trial (P=0.045), indicating more insulin was secreted, but glucose concentration was unchanged in all trials. The study findings demonstrate that a single bout of HIIT affects the insulin response but not the glycaemic response to a glucose load, proffering a potential benefit for metabolic health in older adults.