Squeezing even half an hour of exercise time into a crowded schedule often seems daunting for some people. A new study suggests this may not be necessary. A team of New Zealand researchers found that short bursts of intense exercise before meals controlled blood sugar better than a single, continuous 30-minute session. “Going for a 30-minute walk doesn’t cut it,” Dr. Monique Francois, exercise science and medicine researcher at the University of Otago, told The Australian. “You need to get out there and do intense exercise.”
For the study, Francois and her colleagues enlisted the help of nine participants. The two women and seven men, all between the ages of 18 and 55, had blood test results showing insulin resistance. In random order, the participants completed three separate exercise routines. One, referred to by the researchers as CONT, was a traditional continuous exercise routine consisting of a 30-minute session of moderate-intensity (60 percent of maximal heart rate) before the evening meal only. The second, referred to as exercise snacking (ES), consisted of a set of six, one-minute intense incline walking intervals (90 percent maximal heart rate) finishing half an hour before breakfast, lunch, and dinner meals. The third, referred to as composite exercise snacking (CES), involved six one-minute intervals alternating between walking and resistance-based exercise, and finishing half an hour before breakfast, lunch, and dinner.
The ES and CES routines controlled blood sugar more effectively than the CONT routine, particularly three hours following breakfast and dinner. Across the day, this represented a 12 percent reduction in mean post-meal blood glucose concentration. Plus, there was an additional benefit: The reductions in blood glucose with ES compared to CONT persisted for a further 24 hours across the day following exercise.
“High intensity exercise before meals (particularly breakfast and dinner) may be a more time efficient way to get exercise into people's day, rather than devoting a large chunk of the day," said Francois, who acknowledged that further work is required to substantiate these results. She and her co-researchers will soon publish further studies, including one other acute 24 hour response to high-intensity exercise using different forms of exercise in younger sedentary individuals. “The practical implications of our findings are that, for individuals who are insulin resistant and who experience marked post-meal increases in blood glucose, both the timing and the intensity of exercise should be considered for optimising glucose control," she concluded.