Does defending BB require a lot of bluffing post-flop?

[Wynton]

I keep reading here about people who defend BB a lot more than me, even some who say they defend headsup steal attempts virtually 100% of the time.

But if you are defending the BB 80% or more, doesn't this mean that you have to be willing to bluff post-flop a significant percentage of the time, i.e., even more than one might be expected to bluff in other circumstances?

This question is significant to me because I think that I defend BB less than most here for the reason that I don't have a clear plan how to proceed after the flop. Perhaps if I realize that blind defense assumes an intention to bluff a certain percentage of the time I'll have a better understanding of when it makes sense to defend.