Last month, Web Editor Diane Fennell wrote about a study that measured the effects of walking on the blood glucose levels of people at risk for prediabetes. The research demonstrated that walking for 45 minutes daily significantly lowered participants’ blood glucose levels over a 24-hour period and three hours after lunch. However, blood glucose was also significantly lower three hours after dinner when participants’ walks were divided into three 15-minute segments and completed after each meal, rather than as one 45-minute segment in the morning or afternoon. This study reinforces the notion that physical activity that is spread out over the course of the day can be just as beneficial as, if not better than, one extended bout of exercise.
A new study takes the concept of shorter bouts of walking even further. Published late last month by the American Journal of Clinical Nutrition, the study asked 70 healthy adults to sit for nine hours on three different days. On two of these days, participants were also asked to walk briskly for 30 minutes: on one day as a 30-minute bout before sitting for nine hours, and on the other day as 18 segments of one minute, 40 seconds each, breaking up the sitting into segments of 30 minutes. Participants were given a meal-replacement drink after one, four, and seven hours of sitting on each day, and researchers measured their postmeal blood glucose and insulin levels.
As noted in an article at Diabetes.co.uk, both blood glucose and insulin levels were lowered by walking, compared with the day on which participants sat but did not walk. However, the shorter walking segments lowered blood glucose and insulin levels more than did the extended walking segment. It is not known whether this result occurred because participants expended more energy through the shorter segments, because the timing of exercise segments affected glucose metabolism, or because of some combination of these two effects.
While these results may be encouraging to people who are intimidated by extended bouts of exercise, going for a brief walk every 30 minutes may pose a challenge to people whose jobs demand focused attention for extended periods of time. Of course, this study may demonstrate a need to change how many workplaces are structured, since so many people work in environments where physical activity is difficult to achieve.
What do you think — would you rather exercise in short segments throughout the day or in one longer, concentrated segment? Do you think you could, or do, exercise more vigorously when it is divided into shorter segments? Do studies like these ever affect how you time your physical activity, or do situational factors like your job and family life make most of your choices for you? Leave a comment below!