There is a very easy place to get this one early in the game.
After completing the Prologue and getting a ways into Chapter 1, you will come to a circular open area with several prisoners walking around in the same area. There is a blood trail leading into a room, where you can drop down to a bed on the lower floor. This is the same bed where you can do the Wolf3D "Nightmare" level for Chapter 1. This area comes after several other areas where there were large, armored electric-powered guards pacing the halls.
In the cell with the bed, there are two health packs. One gives +80, and the other +40, which will boost your health above 200 if you consume them both quickly and are already at full health. This unlocks the trophy.