Back to her normal body temperature, Mariela was much more active in her crib.

WSJ: Hypothermia Cure for Babies: Cooling Infants to Battle Brain Damage

Your normal body temperature varies throughout the day it's lower in the morning and higher in the late afternoon and evening.

CNN: Fever

Although normal body temperature is 98.6 degrees Fahrenheit, most U.S. doctors consider 100.4 to 100.9 degrees to represent the start of fever, researchers said.

WSJ: How to Exercise, and Not Eat More

Sharon's heartbeat and body temperature were normal Thursday.

CNN: Sharon undergoes brain scan

There she was wrapped in a cooling blanket that kept her body temperature at about 92 degrees Fahrenheit before it was restored to normal the following day.

WSJ: How Therapeutic Hypothermia Saves Lives of Cardiac Arrest Patients