Can the human Mind be made to work overtime? !!

If it is possible to overwork the Mind, then it will be interesting to probe who is getting this thought of overworking the Mind!! Is there a separate entity within us who is the controller of Mind? Or is the Mind itself creating such an illusion?

When the body and Mind are tired, we feel both have to be rested. Does this indicate that there are two sources of thoughts and counter thoughts! Therefore, what is the reality of the function of the human Mind? Can the function of the Mind be deciphered to the complete satisfaction of our curiosity! Can we be truly convinced with any answer? Or do we meekly nod in satisfaction since we are helpless in getting a completely satisfying answer?