Physical activity, sedentary behaviors, and estimated insulin sensitivity and secretion in pregnant and non-pregnant women

Aims Overweight and obesity during pregnancy raise the risk of gestational diabetes and birth complications. Lifestyle factors such as physical activity may decrease these risks through beneficial effects on systemic glucose homeostasis. Here we examined physical activity patterns and their relationships with measures of glucose homeostasis in late pregnancy compared to non-pregnant women. Methods Normal weight and overweight women without diabetes (N=108; aged 25-35 years) were studied; 35 were pregnant (in gestational weeks 28-32) and 73 were non-pregnant. An oral glucose tolerance test was conducted from which insulin sensitivity and β-cell response were estimated. Physical activity was measured during 10-days of free-living using a combined heart rate sensor and accelerometer. Total (TEE), resting (REE), and physical activity (PAEE) energy expenditure were measured using doubly-labeled water and expired gas indirect calorimetry. Results Total activity (counts/day) was associated with a reduced first-phase insulin response in both pregnant (r=-0.47; 95% CI: -0.70- to -0.15) and non-pregnant women (r=-0.36; 95% CI: -0.56- to -0.12). Pregnant women were estimated to have secreted more insulin (p=0.002) and had lower fasting glucose than non-pregnant women (p<0.0001). Measures of overall physical activity intensity were similar in both groups (p=0.547), but pregnant women spent more time sedentary (p<0.0001), less time in moderate-to-vigorous intensity activity (p<0.0001), had lower objectively measured total activity, and had lower physical activity energy expenditure (PAEE) than non-pregnant women (p=0.045). Conclusions Our findings suggest that physical activity conveys similar benefits on glucose homeostasis in pregnant and non-pregnant women, despite differences in subcomponents of physical activity.