Greetings
I was listening to NPR and the discussion was survival of the fittest. Their discussion didn’t involve physical fitness but it started a conversation between my brother and me about being fit to survive.

We were wondering:
How do you define physical fitness?
Do you have measure you use?
Do you have a daily/weekly program? If so, what is it?

My brother does 3 miles with pack 3 times a week, I can’t remember how long he said it takes him (he’s younger and ex-airborne so he’s faster than me). Then everyday does pushups, crunches, pull-ups, deep knees bends, stretches and kata.
My current program consists of stretching, then running, mostly jogging, for 30min 3 times per week and 3 two minute rounds with the heavy bag twice a week. I’m 47 and this isn’t keeping up with gravity anymore but I still can hike most of the day without problems and run 2 flights of stairs without collapsing. So how fit is fit?

If this has already been discussed in detail, I apologize.
Ian