What can the hearts of animals tell us about our own survival mechanisms?

Dr. Barbara J. Natterson-Horowitz is a cardiologist who works not only with human hearts, but also a wide array of animal hearts, from iguanas to reptiles to tapirs, and more. Her findings gave her insight into a third survival mechanism beyond fight or flight: fainting. At first, it does sound absurd as to why you’d feel nauseated or like shutting down in the face of danger. However, Dr. Natterson-Horowitz then illustrated feelings we all could empathize with, from the humorous hitting Reply All on a personal e-mail to the more horrifying situation of losing a toddler in a supermarket. When presented in a dangerous situation, sometimes the heart slows down instead of speeding up, which causes the animal or person to faint. But why?

Dr. Natterson-Horowitz explains that some predators have heart sensors that track the heartbeat of prey, and if the prey can censor or still that beacon, then it could protect itself. Although unable to ethically test this finding in humans, she was able to seize an opportunity in January 1991 during the First Gulf War in Israel. Missiles and bombs were going off while three women were in labor in a hospital ward. Staff noticed something strange on the fetal heart monitors — the babies’ heart rates were plummeting from 130-140 BPM to a mere 30-40 BPM. These babies had not been born into the world, and yet they were “equipped with the ancient, protective, physiological” mechanism that has been seen across the animal kingdom. Sometimes, when you can’t run away and can’t or won’t fight, being still offers a “powerful form of protection.”

This is only the beginning of uncovering medical mysteries by seeing between hearts and across species. The talk concluded with a thought-provoking sentiment: if more doctors could study hearts beyond the human ones, we may be able to solve more medical mysteries crucial to global health. We may be able to help not only humans, but also all the patients of the world.