All players start the match with 150 health. You must find Items that allow you to heal. There are three such Items in the beta that allow you to restore health after taking damage:
First Aid – Restores small amounts of health very quickly. This is the most common and you can stack five of them in one Inventory slot.
Med Kit – Restores a bit more health but does so a bit more slowly.
Trauma Kit – Restores the most amount of Health and provides an extra +50 health beyond the max. You cannot stack Trauma Kits. Each requires a slot in your Inventory.
In order to heal in Blackout, you must hold the heal button. If you or a teammate is downed, an icon will appear over the player and in the team widget that appears in the left corner of your HUD.