Is there any truth to the aphorism that you can't, it's hard to teach an old dog new tricks? Like do we get more stubborn as we get older? Or is that just a myth? There's a myth that our metabolism slowed down as we got older. That's actually not true. It's how we manage it. We tend to gain weight because of lax dietary choices and less non-exercise physical activity. This was a 84 year old pilot who couldn't fly on his own for 12 years since he could no longer drink alcohol. He has now been diagnosed with Parkinson's disease which will require him to retire at age 70.