That's once a week, 5km @franglaise, not every day! I admit to running 5 or 6 days a week in the eighties, training for marathons and putting in the odd 70 mile week but that is probably what has led to my hips wearing out.
When I was last fit, late 2009 to mid-2010, it was as a result of getting out a couple of lunchtimes a week for 5 or 6 miles with proper runners then doing a solo 12-13 miles slow run on Sundays. This strategy managed to get me to sub-99 minutes for a couple of halves and 45:12 for 10k. More mileage would not have helped, pace was more important at that stage in my career! I'm impressed that you can warm up for 45 mins, I never did more than 5 minutes...
When I was last fit, late 2009 to mid-2010, it was as a result of getting out a couple of lunchtimes a week for 5 or 6 miles with proper runners then doing a solo 12-13 miles slow run on Sundays. This strategy managed to get me to sub-99 minutes for a couple of halves and 45:12 for 10k. More mileage would not have helped, pace was more important at that stage in my career! I'm impressed that you can warm up for 45 mins, I never did more than 5 minutes...