Associations Between 24-hour Activity And Glycemic Response During The Second Trimester Of Pregnancy

Exercise effects on glycemic regulation are well-known, but the impact of 24-hour activity in free-living environments is less explored, especially during pregnancy. PURPOSE: This study examined associations between a 24-hour activity composition (sleep, sedentary [SED], light physical activity [LPA], and moderate-to-vigorous physical activity [MVPA]) and 1-hour 50-gram oral glucose screening test in pregnant women. METHODS: This cross-sectional analysis is part of the Pregnancy 24/7 cohort, conducted across three US university sites (Iowa, Pittsburgh, and West Virginia). Data from the second trimester were collected from 384 women (mean age 30.7 ± 4.3 years) using activPAL3 micro and Actiwatch Spectrum Plus devices, worn for 7 consecutive days to capture the 24-hour activity cycle. Glucose screening data were obtained from medical records. Multivariable linear regression models were applied using a compositional data analysis approach, adjusted for age, pre-pregnancy BMI, race and ethnicity, and study site. RESULTS: On average, participants had a glucose result of 119.6 ± 28.0 mg/dL, and the 24-hour activity compositional means were: sleep (519.3 min [36%]), SED (612.6 min [42%]), LPA (285.6 min [20%]), and MVPA (22.5 min [2%]). In the model using three isometric log-ratio (ilr) coordinates, only one coordinate was statistically significant, suggesting that a specific aspect of the 24-hour activity composition was associated with glucose response. Reallocating 30 minutes from SED to LPA or sleep was associated with estimated reductions in glucose levels of -2.33 mg/dL (95% CI: -4.41, -0.26) and -1.27 mg/dL (95% CI: -2.22, -0.33), respectively. CONCLUSION: These findings suggest that reducing SED time and reallocating to LPA and sleep may contribute to improved glucose regulation during the second trimester of pregnancy. Supported by: R01HL153095