In the aftermath of his stroke, Ariel Sharon has been placed in a medically induced coma. Doctors forecast that he will remain in the coma until at least Sunday. Stateside, Randal McCloy Jr., the lone survivor of the Sago mine explosion, also remains in an induced coma while he recovers from carbon monoxide inhalation. Last October, Daniel Engber explained why and how doctors induce a coma. “Inducing a coma is beneficial because a comatose brain uses less energy—and oxygen—than an awake and alert one,” Engber wrote.