Maternal exercise increases infant resting energy expenditure: preliminary results.

Maternal obesity is associated with lower infant resting energy expenditure (REE), predisposing them to more rapid weight and adiposity gain through early infancy. Maternal exercise (ME) decreases infant adiposity and risk for childhood obesity; however, it remains unknown if this is in part mediated by changes in infant energy expenditure. Thus, we measured REE in 1-month-old infants from pregnant individuals who performed moderate-intensity exercise during pregnancy and compared it to infants from non-exercising controls. We observed higher oxygen respiratory rates (p = 0.003 for VO2 and p = 0.007 for VCO2) and REE (p = 0.002) in infants exposed to exercise in utero, independent of any differences in infant body composition. Furthermore, maternal BMI was significantly and inversely associated with infant REE in the control (r = -0.86, R2 = 0.74, p = 0.029), but not the exercise group (r = 0.33, R2 = 0.11, p = 0.473). Together, these findings associate ME with increasing infant energy expenditure which could be protective of subsequent infant adiposity gain. Clinical Trial: ClinicalTrials.gov Identifier: NCT03838146 and NCT04805502.

Greater reliance on glycolysis is associated with lower mitochondrial substrate oxidation and insulin sensitivity in infant myogenic MSCs.

Individuals with insulin resistance and obesity display higher skeletal muscle production of nonoxidized glycolytic products (i.e., lactate), and lower complete mitochondrial substrate oxidation to CO2. These findings have also been observed in individuals without obesity and are associated with an increased risk for metabolic disease. The purpose of this study was to determine if substrate preference is evident at the earliest stage of life (birth) and to provide a clinical blood marker (lactate) that could be indicative of a predisposition for metabolic disease later. We used radiolabeled tracers to assess substrate oxidation and insulin sensitivity of myogenically differentiated mesenchymal stem cells (MSCs), a proxy of infant skeletal muscle tissue, derived from umbilical cords of full-term infants. We found that greater production of nonoxidized glycolytic products (lactate, pyruvate, alanine) is directly proportional to lower substrate oxidation and insulin sensitivity in MSCs. In addition, we found an inverse relationship between the ratio of complete glucose oxidation to CO2 and infant blood lactate at 1 mo of age. Collectively, considering that higher lactate was associated with lower MSC glucose oxidation and has been shown to be implicated with metabolic disease, it may be an early indicator of infant skeletal muscle phenotype.NEW & NOTEWORTHY In infant myogenically differentiated mesenchymal stem cells, greater production of nonoxidized glycolytic products was directly proportional to lower substrate oxidation and insulin resistance. Glucose oxidation was inversely correlated with infant blood lactate. This suggests that innate differences in infant substrate oxidation exist at birth and could be associated with the development of metabolic disease later in life. Clinical assessment of infant blood lactate could be used as an early indicator of skeletal muscle phenotype.

Exercise during pregnancy Dose: Influence on preterm birth outcomes.

BACKGROUND: Preterm delivery typically increases health risk for neonates and is associated with longer infant hospital stay and financial burden. Prenatal exercise dose (frequency, intensity, type, time, volume) have been shown to influence birth outcomes. Increased prenatal exercise dose could therefore provide a critical reduction in health risk and financial burden in preterm neonates. OBJECTIVE: It was our aim to explore the effects of prenatal exercise dose from a supervised exercise intervention in pregnant women on the occurrence of preterm (<37 weeks gestation) births, and the impact on health outcomes in preterm neonates. STUDY DESIGN: This study is a retrospective, secondary analysis of pooled data from three blinded, prospective, randomized controlled trials. Prenatal exercise dose were assessed in supervised aerobic, resistance, and combination sessions throughout pregnancy. In addition to gestational age, birth weight, resting heart rate, neonatal morphometrics (body circumferences, ponderal index), and health status (Apgar-1 and -5) metrics were obtained for 21 women at birth. One-way analysis of variance tests were used to assess the differences between dose grouped as tertiles, while Pearson correlations determined the association between dose and birth outcomes. RESULTS: Women exercised for an average of 19.6 wks (range: 6 - 21 wks) during pregnancy. Exercise during pregnancy tended to result in later preterm deliveries (p = 0.08). Greater prenatal exercise volume and duration were associated with reduced infant hospital stay post-delivery (p = 0.02). Weekly exercise volume was associated with increased Apgar scores (p = 0.01). CONCLUSION: Increased prenatal exercise volume and duration is associated with improved birth outcomes in preterm neonates.

Exercise FITT-V during pregnancy: Association with birth outcomes.

BACKGROUND: Prenatal exercise improves birth outcomes, but research into exercise dose-response effects is limited. METHODS: This study is a retrospective, secondary analysis of pooled data from three blinded, prospective, randomized controlled trials. Prenatal exercise frequency, intensity, type, time, and volume (FITT-V) were assessed in supervised sessions throughout pregnancy. Gestational age (GA), neonatal resting heart rate (rHR), morphometrics (body circumferences, weight-to-length and ponderal index) Apgar and reflex scores, and placental measures were obtained at birth. Stepwise regressions and Pearson correlations determined associations between FITT-V and birth outcomes. RESULTS: Prenatal exercise frequency reduces ponderal index (R2 = 0.15, F = 2.76, p = .05) and increased total number of reflexes present at birth (R2 = 0.24, F = 7.89, p < .001), while exercise intensity was related to greater gestational age and birth length (R2 = 0.08, F = 3.14; R2 = 0.12, F = 3.86, respectively; both p = .04); exercise weekly volume was associated with shorter hospital stay (R2 = 0.24, F = 4.73, p = .01). Furthermore, exercise type was associated with placenta size (R2 = 0.47, F = 3.51, p = .01). CONCLUSIONS: Prenatal exercise is positively related to birth and placental outcomes in a dose-dependent manner.

Myogenically differentiated mesenchymal stem cell insulin sensitivity is associated with infant adiposity at 1 and 6 months of age.

OBJECTIVE: In adults, skeletal muscle insulin sensitivity (SI ) and fatty acid oxidation (FAO) are linked with a predisposition to obesity. The current study aimed to determine the effects of maternal exercise on a model of infant skeletal muscle tissue (differentiated umbilical cord mesenchymal stem cells [MSCs]) SI and FAO and analyzed for associations with infant body composition. METHODS: Females <16 weeks' gestation were randomized to either 150 min/wk of moderate-intensity aerobic, resistance, or combination exercise or a nonexercising control. At delivery, MSCs were isolated from umbilical cords and myogenically differentiated, and SI and FAO were measured using radiolabeled substrates. Infant body fat percentage (BF%) and fat-free mass were calculated using standard equations at 1 and 6 months of age. RESULTS: MSCs from infants of all exercisers had significantly (p < 0.05) higher SI . MSC SI was inversely associated with infant BF% at 1 (r = -0.38, p < 0.05) and 6 (r = -0.65, p < 0.01) months of age. Infants with high SI had lower BF% at 1 (p = 0.06) and 6 (p < 0.01) months of age. MSCs in the high SI group had higher (p < 0.05) FAO. CONCLUSIONS: Exposure to any type of exercise in utero improves offspring SI and could reduce adiposity in early infancy.