Potential underlying mechanisms for greater weight gain in massaged preterm infants.

In this paper, potential underlying mechanisms for massage therapy effects on preterm infant weight gain are reviewed. Path analyses are presented suggesting that: (1) increased vagal activity was associated with (2) increased gastric motility, which, in turn, was related to (3) greater weight gain; and (4) increased IGF-1 was related to greater weight gain. The change in vagal activity during the massage explained 49% of the variance in the change in gastric activity. And, the change in vagal activity during the massage explained 62% of the variance in the change in insulin. That the change in gastric activity was not related to the change in insulin suggests two parallel pathways via which massage therapy leads to increased weight gain: (1) insulin release via the celiac branch of the vagus; and (2) increased gastric activity via the gastric branch of the vagus.