When I am working with this attitude of karma yoga, there's a natural peace which comes. You sleep happily. Somehow you are not entangled with the world anymore. And even deeper kind of peace comes when not just externally you're karma yoga, but internally the mind is given to God. That is at some time, even devotional thoughts, pure devotional thoughts,. Even that seizes at least a couple of times in a day, shut down everything. And enjoy the deepest possible silence.