I’ve never put that much time or effort into running. I just ran a 2:59 marathon off of around 3 months of 70mpw easy jogging. Never did any workouts. I spend a lot of time outdoors hiking so I had ok cardio before hand.
I don’t want to spend this much time running any more but would like to maintain my cardio as much as possible. What is the minimum amount of time running I can get away with and maintain this level of fitness?
Why don't you just look up CDC advice on the matter - whatever they say, I forget if it is 30 min or 1 hour a day of moderate activity (i would interpret this as zone 2)
If you ran 2:59 off of 70 mpw with no workouts and want to be able to continue running 2:59 by running less, you're going to have to start doing workouts. You could probably pull it off with 41-46 mpw if you structured it correctly. Maybe something like this:
Mo off
Tu 6
We 10 (1.5 w/u, 6 * 1 mile @ 10k pace, 1.0 c/d)
Th 6
Fr off
Sa 4
Su 15-20 (incorporating marathon pace)
The theory says 70% of your last volume. So around 50mpw should do the trick.