The loving-kindness exercise was interesting. I enjoyed it for the most part, and had no problem sending out healing and kindness. I wasn't quite able to take in the suffering. I am going t try doing this exercie on a regular basis, (after I am moved) and see if I can improve. Yes, I would probably recommend it to others on an individual basis. I did find it very beneficial and felt all warm and fuzzy with sending out healing.
A mental workout could be anthing that challenges your mind. Trying new ideas and practices. The loving-kindess would be considered a mental workout. I also work on a websitecalled Luminosity which is supposed to keep your menta faculties sharp. It makes you use skills that are dormant like math, memory, observing and other mental activies. It is supposed to help keep your mind young and well tuned. Doing mental workouts like these make you feel better about yourself and sharper.