Adrenaline

Adrenaline is a perk in the Survival difficulty of Fallout 4 and in Fallout 76.

Effects
Each rank of the Adrenaline perk provides a +5% bonus to one's damage output, for a maximum of +50%, balancing out the fact that Survival difficulty makes combat significantly more lethal. The bonus to damage increases with the more kills one obtains (from hostile targets or otherwise), and appears to increase by one rank for every five kills. However, sleeping causes accumulated ranks of Adrenaline to subside at a rate of one rank per hour slept.