>Meanwhile at trail running meets, I bump into 60 year olds still giving some 35 year olds a run for their money.

Interrupt that 60 year old's sleep twice a night with a newborn crying, add a bunch of new responsibilities, and I'll be impressed if he even makes it to the meet.

You're comparing people who have made exercise their #1 priority in life to people who have made their kids and supporting their families financially their top 2 priorities. It's a bullshit comparison.