I think the problem is that our civilization is built in the idea of comfort and economic specialization. I don't think our bodies are prepared to that sort of pattern where you stay inactive for 5 hours, while your brain is still very active, and stop to run non stop for 1 hour. So we either sit thinking about civilized work, or do short but very intense physical activity to compensate the accumulation of stress. I…
That may be true, but they will be soon enough thanks to evolution.
I am not advocating inactivity, in fact I enjoy walking every day very much.