By the shortest and most direct route, my commute is only 4½ miles each way. I enjoy every one of them, even going to work.
Now what makes me physically feel best afterwards is a combination of miles and intensity. Ten to 25 miles at zone four intensity really feels good.
But even a trip to the grocery store (0.88 miles round trip) does it for headspace.
Zone Four intensity? It even sounds rough. Wassat?
PS I went and looked that up. It means working really hard for as long as you can, until you nearly give out. Right?
There were an awful lot of calculations, discussions of heart recovery rates and lactase in the blood - but this suffices.