Researchers have suggested that brief bursts of intense exercise before meals helps control blood sugar in people with insulin resistance more effectively than one daily 30-minute session of moderate exercise.The study used a cross-over design, mean-ing that each participant acts as their own control, and questions can be answered with a much smaller number of partici-pants.Nine individuals (2 women, 7 men) were recruited. All had blood test results show-ing insulin resistance, were not on car-diovascular or diabetic medication, were aged 18-55 years (mean age 48), and had a mean BMI 36 kg/m2. They included two newly diagnosed type 2 diabetics only de-tected as part of the screening.The participants completed three sepa-rate exercise interventions in ran-domised order. Measures were recorded across 3 days with exercise performed on the middle day, as either: (1) traditional continuous exercise (CONT), compris-ing one 30 min moderate-intensity (60 per cent of maximal heart rate) session of incline walking before dinner (even-ing meal) only; (2) exercise snacking (ES), consisting of 6×1 min intense (90 per cent maximal heart rate) incline walking in-tervals finishing 30 min before breakfast, lunch and dinner, with one minute slow walking recovery time after each minute of intense exercise; or composite exercise snacking (CES), encompassing 6X1 min intervals alternating between walking and resistance-based exercise (with a one-minute slow walking recovery minute after each minute of exercise), again fin-ishing 30 min before breakfast lunch and dinner.ES and CONT were matched for energy usage, whereas ES and CES were matched for time but CES provided a brief workout for all of the body’s major muscle groups across the day. Meal timing and composi-tion were the same for all three exercise interventions, and monitored using diet records, daily verbal discussion, and di-etary analysis software.Female participants completed the trials in the early follicular phase of their men-strual cycle (across three separate cycles), whereas male participants had a minimum of 7 days between trials.The researchers found that the ES and CES routines controlled blood sugar more effec-tively than the CONT routine, particularly 3-h post-meal glucose following breakfast (17 per cent reduction compared to no exer-cise) and dinner (13 per cent reduction com-pared to CONT). Across the day this repre-sented a 12 per cent reduction in mean post-meal blood glucose concentration. The effect of the pre-lunch ES on blood glucose levels after lunch was unclear. Moreover, the reductions in blood glucose with ES compared to CONT persisted for a further 24 hours across the day follwing exercise.The new research has been published in the journal Diabetologia.
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