Meaning of diving reflex

div'ing re"flex

Pronunciation: [key]
— Physiol. Physiol.
  1. a reflex of humans, other mammals, reptiles, and birds, triggered by immersion in cold water, that slows the heart rate and diverts blood flow to the brain, heart, and lungs: serves to conserve oxygen until breathing resumes and to delay potential brain damage.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.