We purchased an aerobic exerciser a month ago.  I really enjoy using it and a very painful knee is feeling much more comfortable and I am walking more normally.  I expect this improvement to continue.  I certainly feel more energetic and am sleeping much better.  It is nice to know that I can maintain my good health by using The Chi Machine every day.  I am now up to six minutes three times daily and I look forward to using it, especially when I am tired.