try this, I haven't tested it, and never used some of these functions so look out for errors :P.
var_NearDeath = 0
local function ComeAgains()
if localPlayer:Health() <= 25 then
var_NearDeath = 0
else
var_NearDeath = 1
end
end
local function PostProcessing()
local EleToGo = {"bloom"}
if( !var_NearDeath ) then
return table.HasValue(EleToGo, element)
else
return false
end
end
hook.Add( "PostProcessPermitted", PostProcessing )
hook.Add( "Think", ComeAgains )
Should make your screen blurry when ur lower than 25 health...