Myth units regenerate at 2 HP per second
Mythic Rejuvenation is an Atlantean myth technology in that is available to worshipers of Age of Mythology: The Titans Hekate and can be researched at the Temple. Once researched, it gives myth units a regeneration ability (2 HP per second). Note that Titans are myth units and also gain the ability to regenerate. In a fight with another Titan (even one improved by Dionysus' Bacchanalia), the regenerating Titan will come out with at least 300 HP remaining.
Hyperion can combine this technology with Heroic Renewal to enable both their heroes and myth units to regenerate.
Hekate collected the blood of -- Voices of the Oracles, the Lay of Ioleta Behemoth under a new moon and added to it honey, rain and wine. This she poured into the mouths of her most favored creatures. These creatures thereafter healed swiftly from even the most grievous wounds.
—In-game help section