Medicine & Science in Sports & Exercise:
B-29 Exercise is Medicine/Poster - Exercise is Medicine for Special Populations: JUNE 1, 2011 1:00 PM - 6:00 PM: ROOM: Hall B
Mikus, Catherine R.; Libla, Jessica L.; Oberlin, Douglas J.; Boyle, Leryn J.; Thyfault, John P.
1University of Missouri, Columbia, MO. 2University of Missouri and Harry S. Truman Memorial VA Hospital, Columbia, MO.
(No relationships reported)
Postprandial glucose excursions (PPG; difference between pre- and post-meal blood glucose concentrations) better predict adverse cardiovascular outcomes than HbA1c in those with and without type 2 diabetes. Exercise training effectively lowers HbA1c and improves insulin sensitivity in persons with type 2 diabetes; however, HbA1c provides only an index of average blood glucose over 2-3 months and does not adequately capture PPG.
PURPOSE: To determine the impact of a week-long aerobic exercise intervention on PPG in free-living individuals with type 2 diabetes.
METHODS: Using continuous glucose monitors, we quantified mean PPG in sedentary, obese volunteers with non-insulin dependent type 2 diabetes during three days of habitual activity and during the final three days of a seven-day exercise program (60 min·d-1 moderate intensity walking and cycling). Oral glucose tolerance tests (OGTT) were performed on the morning immediately following each monitoring period. Dietary intake was standardized across monitoring periods, and additional snacks were provided to compensate for the energy cost of exercise.
RESULTS: Increasing physical activity (5,801 ± 770 to 10,894 ± 791 steps·d-1) for seven days in obese, sedentary patients with type 2 diabetes (N=13, Age 53 ± 2 y, BMI 34.1 ± 1.3 kg·m-2, HbA1c 6.6 ± 0.2%) attenuated PPG up to 40% (1.3 ± 0.2, 2.9 ± 0.3, 3.1 ± 0.3, and 2.4 ± 0.3 mmol·l-1 pre-exercise to 0.8 ± 0.1, 2.1 ± 0.2, 2.0 ± 0.2, and 1.3 ± 0.2 mmol·l-1 post-exercise at 30, 60, 90, and 120 min post-meal, respectively, p < 0.05). Fasting blood glucose (7.0 ± 0.4 to 6.8 ± 0.4 mmol·l-1) and insulin (66.8 ± 8.5 to 65.9 ± 7.1 pmol·l-1) did not change, nor did glucose (1530 ± 93 to 1506 ±77 glucose AUC0-120) and insulin (34,986 ± 5,502 to 29,304 ± 4,188 insulin AUC0-120) responses to the OGTT; however, the Matsuda insulin sensitivity index increased from 3.0 ± 0.3 to 3.6 ± 0.6 (p < 0.05). Body weight and composition were unchanged.
CONCLUSIONS: Acute alterations in physical activity significantly lower postprandial glucose excursions, an independent predictor of adverse cardiovascular outcomes, in free living persons with type 2 diabetes. Further, these changes occurred independent of changes in adiposity and were not captured by OGTT.
Supported by MU ICATS, NIH T32 AR-048523, Diabetes Action Research and Education Foundation, and VHA CDA.