on topic wrote:
But yes, recovery runs "count" towards weekly mileage.
It's a semantic distinction you're making - some runs "count" and are stressful on the body, and other runs "don't count" and do not stress the body (only recover it). That's not how the body works. Every run is stressful to some extent, even recovery runs.
If you are very fit, then a recovery run might not count to milage. It can be even junk miles.
If you are unfit, every run or even a walk can count. It depends on your individual fitness level and intensity.
That there is a minimum intensity needed to improve cardirespiratory fitness is really super easy to understand, outerwise sitting in a chair, using the elevator would be a training.