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.