Relative contribution of physical activity to neonatal oxygen consumption.
To explore the relevance of distinguishing between resting and global energy expenditure in newborn infants, oxygen consumption (VO2) was measured during extremes of physical activity in 17 parenterally fed newborn infants with a large range of body weights (1.0-3.4 kg) and gestational ages (28-41 weeks). Under constant nutrient intakes, each infant served as his/her own control when comparing VO2 during resting conditions and spontaneous intense physical activity, called exercise. VO2 was significantly correlated with body weight at rest (r = 0.96). But during intense activity, the better predictor of exercise-induced VO2 was body weight in the smaller infants (< 2.0 kg) and gestational age in the larger infants (> 35 weeks). The difference in VO2 between both levels of activity represented the oxygen cost of exercise, which decreased (P < 0.01) with body weight. For clinical purposes, the physical activity of low-birth-weight infants does not contribute substantially to their energy balance.
Billeaud
C
C
Perinatal Service and Research Center, Hospital Sainte-Justine, Montreal, Canada.
Piedboeuf
B
B
Jéquier
J C
JC
Chessex
P
P
D001481:Basal Metabolism; D001724:Birth Weight; D004734:Energy Metabolism / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn / Q000502:physiology*; D007234:Infant, Premature / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology*