Health Regen is a stat that heroes start with and can obtain more through items. Per second, heroes will regenerate their amount of health regeneration as health. It must not be confused with healing, which refers to the ability of helping both the player and other players regain health.
As players take damage, their health will slowly recover over time. While dead, players will not be able to regenerate health. Standing in base will quickly regenerate the player's health, allowing them recover from fights. Most sources of health regen are additive (health regen), with a few instead being multiplicative (Max health regen). Both types of regen do not increase by leveling up.