Don't let this happen to you:
White (Karpov) risked nothing, because he was able to exchange off many pieces; so he did not have to worry about any Kingside attack. All Karpov had to do was squeeze and prod his opponent's weaknesses. Not a situation you want to get against any opponent, let alone Karpov.
Below are some defensive schemes for dealing with the dreaded minority attack that Black faces when playing the Queen's Gambit Declined.
Play a5, force a3 and b4 and then play Bd6 to put pressure on the a3 pawn
Play a6 to stop b5, wait for White to play b5 and then play a5
Why can't White take the c6 pawn?
Play cxb5 followed by a5
This strategy is not mentioned much, but it can be very effective. This strategy is most effective when the game is headed or already in an endgame; especially a Knight endgame (as Knights are weak against passed rook pawns).
Don't play a6, and meet b5 with c5
White will be hitting nothing!
Stop White from playing b5, by playing b5 yourself!
Which Defense Should You Employ?