Postprandial interval walking-effect on blood glucose in pregnant women with gestational diabetes.

BACKGROUND: During pregnancy, postprandial hyperglycemia may increase the risk of complications such as fetal macrosomia. However, evidence on beneficial effects of physical activity on postprandial hyperglycemia is sparse. OBJECTIVE: This study aimed to investigate the effect of 20 minutes of postprandial interval walking on glycemic control and glycemic variability in pregnant women diagnosed as having gestational diabetes mellitus. STUDY DESIGN: A crossover controlled trial including 14 pregnant women (gestational age 31.8±1.3 weeks) diagnosed as having gestational diabetes mellitus (75 g oral glucose load with 2-hour venous plasma glucose of ≥9.0 mmol/L) was conducted. Participants completed a 4-day intervention period and a 4-day control period with 3 days in between. In each study period, participants received a fixed and identical diet. In the intervention period, participants engaged in 20 minutes of postprandial interval walking after breakfast, lunch, and dinner. Interval walking comprised alternating 3 minutes of slow and fast intervals. Interstitial glucose concentrations were determined during both study periods with a continuous glucose monitor. The mixed effects model was used to compare differences between exercise and no exercise. RESULTS: Of note, 20 minutes of postprandial interval walking significantly reduced glycemic control during daytime hours relative to the control period (4-day mean glucose, 5.31 [5.04-5.59] vs 5.53 [5.25-5.81] mmol/L [95.6 (90.7-100.6) vs 99.5 (94.5-104.6) mg/dL]; P<.05). On each individual trial day, interval walking significantly reduced glycemic control during daytime hours on day 1 (mean glucose, 5.19 [4.92-5.47] vs 5.55 [5.27-5.83] mmol/L [93.4 (88.6-98.5) vs 99.9 (94.9-104.9) mg/dL]; P=.00), day 2 (mean glucose, 5.32 [5.05-5.60] vs 5.57 [5.29-5.84] mmol/L [95.8 (90.9-100.8) vs 100.3 (95.2-105.1) mg/dL]; P=.00), and day 3 (mean glucose, 5.27 [5.00-5.54] vs 5.46 [5.19-5.74] mmol/L [94.9 (90.0-99.7) vs 98.3 (93.4-103.3) mg/dL]; P=.00), but not on day 4. CONCLUSION: A total of 20 minutes of postprandial interval walking seems to be an effective way to control postprandial glucose excursions in women with gestational diabetes mellitus.

Maternal prepregnancy body mass index and physical activity during pregnancy assessed by accelerometer.

BACKGROUND: Maternal prepregnancy overweight and obesity increase the risk of adverse pregnancy outcomes, whereas physical activity during pregnancy has a beneficial effect on both the mother and the fetus. Limited data are available on how maternal prepregnancy overweight and obesity affect physical activity during pregnancy. OBJECTIVE: The purpose of this study was to describe the association between prepregnancy body mass index and physical activity during pregnancy. STUDY DESIGN: An observational prospective cohort study of 400 singleton pregnant women who were attending routine antenatal care at Aarhus University Hospital, Denmark (2010-2015), was conducted. Physical activity was assessed by an accelerometer (SenseWear Armband) for 7 days for each trimester. Participants were stratified in 3 different groups of prepregnancy body mass index: normal weight (body mass index <25 kg/m2), overweight (body mass index 25-29.9 kg/m2), and obese (body mass index ≥30 kg/m2). Physical activity was measured as the number of steps per day, metabolic equivalent of task per day, time in moderate- to vigorous-intensity physical activity (>3 metabolic equivalent of task), and time in vigorous-intensity physical activity (>6 metabolic equivalent of task). Linear regression and multilevel mixed-effects models were used to explore the association between prepregnancy body mass index and physical activity variables during pregnancy. RESULTS: We found an inverse linear relationship between prepregnancy body mass index and both mean number of steps per day and mean metabolic equivalent of task per day (P<.001). At baseline, women with normal weight walked a median of 1214 steps per day (95% confidence interval, 576-1852) more than women who were obese (P<.05), and women who were overweight walked a median of 948 steps per day (95% confidence interval, 218-1677) more than women who were obese (P<.05). Independent of prepregnancy body mass index, all variables of physical activity decreased over the course of pregnancy (P<.05), with the greatest decrease in the third trimester. CONCLUSION: Maternal physical activity measured by an accelerometer decreased across pregnancy independent of maternal body mass index status and was inversely associated with prepregnancy body mass index. Thus, being overweight or obese before pregnancy increased the risk of sedentary behavior during pregnancy.

Cycling reduces blood glucose excursions after an oral glucose tolerance test in pregnant women: a randomized crossover trial.

The aim of this study was to evaluate the effect of an acute bout of cycling immediately after oral glucose intake on glucose metabolism in pregnant women at risk for gestational diabetes mellitus (GDM). Fifteen pregnant women with BMI ≥ 27 kg/m2 were enrolled in a randomized crossover controlled study and underwent two oral glucose tolerance tests (OGTTs) ingesting 75 g of glucose followed by either 20 min of stationary cycling at moderate intensity (65%-75% maximal heart rate) or rest. Using continuous glucose monitors, glucose was measured up to 48 h after the OGTT. Glucose, insulin, and C-peptide were determined at baseline and after 1 and 2 h. One hour after glucose intake, mean blood glucose was significantly lower after cycling compared with rest (p = 0.002). Similarly, mean glucose peak level was significantly lower after cycling compared with after rest (p = 0.039). Lower levels of insulin and C-peptide were observed after 1 h (p < 0.01). Differences in glucose measurements after 2 h and up to 48 h were not statistically different. We found that 20 min of cycling at moderate intensity after glucose intake reduced blood glucose excursions in pregnant women at risk for GDM. ClinicalTrials.gov Identifier: NCT03644238. Novelty Bullets In pregnant women, we found that cycling after glucose intake resulted in significantly lower glucose levels compared with rest. The exercise intervention studied is feasible for pregnant women and could be readily used to reduce glucose excursions.