Again, the unfortunate side of this is two things:
- Nobody can truly agree on what length of time, intensity, frequency, etc, really constitute "chronic cardio" and this CANNOT be done, because people have different levels of fitness so what to some may be over-doing it, to more conditioned people it's really just a way to get the blood flowing.
- Even if such a consensus were to be agreed upon, it's still up to the individual to decide if they want to subscribe to that or not. If Mark were to hop on and say "From now on, daily 2 mile jogs are chronic cardio... my children go on to the world and share my message" some people would say "Yep, that sits about right with my preconceived notion of chronic cardio" while others would think Mark has lost his marbles and wouldn't listen for a second.
Personally I think I need to actually jog more, I'm gaining an interest in Parkour so in order to train specifically towards learning some of those movements I have to get used to moving my feet in between feats (jumping, climbing, etc) so I need to work on my stamina. I think any run further than 3-4 miles would at this point for me be hard to complete and that's kind of absurd considering I'm not carrying much with me, but it's a "muscle" that's under-developed because I haven't been on a proper jog in a long while. Even before finding MDA I would try to spice up my jogs by leaping over small obstacles, being careful where I stepped on, sprinting, etc, so that it wouldn't be as boring. I want to have one hill sprint session every 10 days for stamina and strength development and a more traditional jog of up to 5 miles also every couple of days so I can start developing my endurance and stamina.
As far as I'm concerned since a lot of us here are into training that's "functional" and translates into real world movement we should be doing more running. I'm noticing a lot of endurance gains in my strength training (is that an oxymoron?) so I should strive for a more complete body by making sure I won't gas out after 3 miles.
You have to strive for balance.
You also have to remember these are all nothing but guidelines, you make the final decisions.