The recruit, who is in his 40s, had just finished a run and was stretching when he collapsed and stopped breathing. Another recruit came to his rescue, performing CPR and using a defibrillator to keep him alive until paramedics arrived.
Commissioner Richard Ross says the recruit was taken to Jefferson-Torresdale Hospital for treatment.
"They did have to sedate him and intubate him," Ross said. "He will be transferred into ICU for further observation. They do have a pulse, and he's breathing with assistance at this point in time."
The recruit's name is not being released at this time, and there's no word on why he collapsed.