Circulating Long-Chain Acylcarnitine Concentrations are Not Affected by Exercise Training in Pregnant Women with Obesity
The purpose of this study was to determine the effect of exercise during pregnancy in sedentary women with obesity on longitudinal changes in long-chain acylcarnitine (LC-AC) concentrations. We hypothesized that exercise training would significantly decrease circulating LC-ACs throughout gestation compared to a non-exercise control group. Pregnant women with obesity considered otherwise healthy [n=80, mean ± SD; body mass index (BMI): 36.9±5.7 kg/m2] were randomized into an exercise (n=40, aerobic/resistance 3x/week, ~13th gestation week until birth) or a non-exercise control (n=40) group. At gestation week 12.2 ± 0.5 and 36.0 ± 0.4, a submaximal exercise test was conducted, and indirect calorimetry was used to measure relative resting energy expenditure (REE), as well as respiratory exchange ratio (RER) at rest. Fasting blood samples were collected and analyzed for LC-AC concentrations. Fitness improved with prenatal exercise training; however, exercise training did not affect circulating LC-AC. When groups were collapsed, LC-ACs decreased during gestation (combined groups, P < 0.001), whereas REE (kcal·kg-1·d-1, P = 0.008) increased. However, average REE relative to FFM (kcal·kgFFM-1·d-1) and RER did not change. There was an inverse relationship between the change in RER and all LC-ACs (except C18:2) throughout gestation (C14: r = -0.26, P = 0.04; C16: r = -0.27, P = 0.03; C18:1: r = -0.28, P = 0.02). In summary, a moderate intensity exercise intervention during pregnancy in women with obesity did not alter LC-ACs concentrations versus control, indicating that the balance between LCFA availability and oxidation neither improved nor worsened with an exercise intervention.