Stamina too - running and hours of walking. This is an area where I struggle. I was in tip top shape then life happened including a lung operation that just wiped me out. Took me a long time to fully recover. Getting back into shape now that I've put on some pounds is something I must do. I need to be as strong and energetic as I used to be. Otherwise, everything I share with others is for their survival, not mine. Thanks for this excellent post. Very well presented. I look forward to Part 2!