I know what it's like to see your great-grandkids and not be able to do everything they want.
My wife and I weren't able to do the activities we do today. We were happy about retirement and started to "enjoy it" just watching tv and staying home before we know it we started having trouble doing things that used to be easy. We weren't physically active and started to notice we were physically declining.
The turning point was when our great-granddaughter wanted to play outside and was struggling to keep up with her. We knew it was time to make a decision and decided to join the gym and start being active every day, even if it was small things. We enjoyed it and had fun with it. Slowly but surely we felt ourselves getting stronger and more limber. Everyone can do it and you owe it to your family and partner to be here to create as many memories as possible with them.