Damage script not dealing damage at a constant rate?

I am trying to create an NPC that damages itself, 10 damage per second. I wrote this script in order to complete said task:

local ConchHealth = script.Parent.Health

while wait(1) do
	ConchHealth = ConchHealth - 10
end

This script is placed inside of the Humanoid.

Things I've Tried:

Placing it elsewhere in the NPC.

Testing to see if it was the while loop (It wasn't).

Any help is appreciated.