Related to the What's Your Mental Age? thread, for discussion, how much is your mental age tied directly to your physical age, hormones, health, and condition? We view old people as being set in their ways and don't like to do a lot. Let's pretend that a miracle drug unlocked the cell reproduction cycle allowing people to maintain a 20 year old like body for 100 years, with a total lifespan of 400 years. How do you think these people would act on their 100th birthday- youthful and energetic or old, want to stay at home type people? I think you'd act as young as you feel, but I could see possible mental issues assiciated with an extended life for some people. And I imagine some 100 year old people might become less tolerant and set in their ways too, but physically, there would nothing holding them back.