The Effects of Exercise on Body Weight and Circulating Leptin in Premature Infants

OBJECTIVE: To assess the effect of daily movements on weight gain, serum leptin, and insulin-like growth factor I (IGF-I) in premature infants. STUDY DESIGN: Twenty very-low-birth-weight premature infants were matched andrandomized to a dally movement (n=10) and control ginups (n=10). Daily movement consisted of passive range of motion with gentle compression of both the upper and lower extremities 5 days per week for 4 weeks. RESULTS: Daily movements led to a significant increase in weight gain (784 ′ 51 vs 608 ′ 26 g in movements and controls respectiveh, p<0.02), and to a significant increase in leptin (0.60′0.19 is 0.13′0.06 ng/ml in movements and controls, respectively, p<0.05). Changes in body weight correlated with changes in serum leptin (r=0.48, p<0.03). IGF-I also increased following daily movements (18.8+4.1 vs 9.2′4.1 ng/ml in movements and controls, respectively); however this increase was not statistically significant. CONCLUSION: A relatively brief range of motion daily movement intervention was associated with greater weight gain and increased leptin levels in very-low-birth-weight premature infants. This may suggest that at least part of the daily movements associated with increase in body weight resulted from an increase in adipose tissue.