Acute Effects of Postabsorptive and Postprandial Physical Activity on Glycemia and Inflammation

Physical activity performed in the postprandial state has the ability to blunt postprandial glycemia acutely, even as a result of very light or small amounts of postprandial physical activity. Postprandial physical activity decreases postprandial glycemia more effectively than activity performed in the post-absorptive state. However, studies comparing postprandial and postabsorptive physical activity have measured glycemic outcomes in only short periods of time (hours) or have used a very large dose of physical activity.

Physical activity have the ability to entail an acute increase in markers of systemic inflammation.Previous studies has also shown that systemic inflammation is increased during glycemic spikes, such as after a high carbohydrate load. Therefore the effect of postprandial physical activity is difficult to predict. One one hand it might increase markers of systemic inflammation. On the other hand it might decrease systemic inflammation as a result of a blunting effect on postprandial glycemia. The effect of physical activity after carbohydrate intake might therefore also differ from postabsorptive physical activity.

Purpose of the study: I) The investigators hypothesized that light physical activity performed in the post-prandial sate decrease blood glucose in a day and night cycle compared to the same activity performed in the postabsorptive state and a control day. II) To test whether postabsorptive and postprandial light physical activity do affect markers of systemic inflammation different.

12 participants diagnosed with hyperglycemia but not on hypoglycemic medication took part in a randomized cross-over trial with 3 test days. A control day with no physical activity, and two days similar to the control day except that one of them contained a one hour bout of treadmill walking prior to breakfast and the other a similar exercise bout after breakfast. Continuous glucose monitoring was performed from start of exercise / breakfast until the morning next day (at least 22 hours). Venous blood was also sampled at given timepoints (before exercise / before breakfast, and 1.5, 2.5, 3.5 and 24 hours after breakfast. Dietary intake was individually standardized prior to and during test days.