You can get all 3 Health Perks in the Research Center in the Prologue.
When you first get control of your pistol, coming off the elevator, take out the 2 guards. Wesley will ask you to look around. There is a Health Upgrade in the back right storage room along with a TON of ammo. Ignore health items for now and load up on ammo. Eventually Wesley will tell you to use the radio to call for information. Starting with the health in the storage area make a bee line for the second row of desks in the main room. There are 2 to 3 health packs at each of the three desks and then 3 more on the back right desk. Grabbing all of these will boost you over 250 and get Health Perk I and II. Now quickly use the radio and enemies will start spawning. While you are still above 100 health kill 5 to get Health Perk III.