Dosing exercise as brief, intense ‘exercise snacks’ before meals may be a time-efficient and effective approach to improve glycemic control in individuals with insulin resistance, researchers in New Zealand reported.
Nine individuals were randomized to 3 exercise regimens: traditional continuous exercise of 30 minutes of moderate-intensity (60% of maximal heart rate) incline walking before dinner; exercise “snacking” consisting of six 1-minute intense (90% of maximal heart rate) incline walking intervals 30 minutes before each meal; or composite exercise snacking of six 1-minute intervals alternating between walking and resistance-based exercise, 30 minutes before meals.
The research, which was published online May 8, can be downloaded from Diabetologia, the journal of the European Association for the Study of Diabetes.
Exercise snacking attenuated mean 3-hour 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 continuous exercise following dinner (0.7±1.5 mmol/L below continuous exercise; P=0.04). Exercise snacking also reduced 24-hour mean glucose concentration by 0.7±0.6 mmol/L (P=0.01) and this reduction persisted for the subsequent 24-hour period (lower by 0.6±0.4 mmol/L vs. continuous exercise, relative to their baselines; P=0.01). Walking and resistance-based intervals were just as effective as just walking intervals (P>0.05 for all glycemic variables) at improving glycemic control.
Researchers concluded, “Dosing brief bouts of intense exercise immediately before breakfast, lunch and dinner (‘exercise snacking’) reduced postprandial and subsequent 24 hour glucose concentrations in an insulin-resistant population when compared with a single 30 minute bout of moderate, continuous exercise undertaken before the evening meal. Moreover, these benefits persisted for the 24 hours following the exercise intervention. In contrast, a bout of continuous exercise failed to lower postprandial glucose after dinner or to improve glycemic control the day following exercise.&rdquo