All the people I know in their 60's 70's still running are doing like 2-5 miles per day maximum. Few ran marathons more than casually. All of them wear shoes. B

All the people I know in their 60's 70's still running are doing like 2-5 miles per day maximum. Few ran marathons more than casually. All of them wear shoes. But all of them had to iterate a lot to find shoes that work for them. Running two marathons per week strikes me as way beyond excessive, if the goal is just to be running later in life.