Abstract
Aims/hypothesis The aim of this study was to investigate whether small doses of intense exercise before each main meal ('exercise snacks') would result in better blood glucose control than a single bout of prolonged, continuous, moderate-intensity exercise in individuals with insulin resistance.
Methods Nine individuals completed three exercise interventions in randomised order. Measures were recorded across 3 days with exercise performed on the middle day, as either: (1) traditional continuous exercise (CONT), comprising 30 min moderate-intensity (60% of maximal heart rate [HRmax]) incline walking before dinner; (2) exercise snacking (ES), consisting of 6 x 1 min intense (90% HRmax) incline walking intervals 30 min before each meal; or (3) composite exercise snacking (CES), encompassing 6 x 1 min intervals alternating between walking and resistance-based exercise, 30 min before meals. Meal timing and composition were controlled within participants for exercise interventions.
Results ES attenuated mean 3 h postprandial glucose concentration following breakfast (by 1.4 +/- 1.5 mmol/l, p=0.02) but not lunch (0.4 +/- 1.0 mmol/l, p=0.22), and was more effective than CONT following dinner (0.7 +/- 1.5 mmol/l below CONT; p=0.04). ES also reduced 24 h mean glucose concentration by 0.7 +/- 0.6 mmol/l (p=0.01) and this reduction persisted for the subsequent 24 h (lower by 0.6 +/- 0.4 mmol/l vs CONT, relative to their baselines; p=0.01). CES was just as effective as ES (p>0.05 for all glycaemic variables) at improving glycaemic control.
Conclusions/interpretation Dosing exercise as brief, intense 'exercise snacks' before main meals is a time-efficient and effective approach to improve glycaemic control in individuals with insulin resistance.