A friend of mine has significant osteoporosis issues. She got lots of free DVDs and exercise instructions from national osteoporosis foundation. Essentially lots of strenght training, yoga, etc. Low cost, low impact, good return. Might be worth checking out. I tend to do some really intense, high impact, short term 'work outs'...lots of very heavy lifting and major resistense work but very sporadic. Not an ideal plan but it is my life.