A few weeks ago I was inspired to do an ultra-high intensity bike workout: go all out for 30 seconds, then 60% max for 30 seconds, repeat for 10 sets. Just prior to doing this I went for a 30 minute, brisk walk. Although the bike workout was hard, it was not devastating. A week later I was inspired to do the bike workout again, but this time I didn’t precede it with the 30 minute brisk walk. I felt like puking my guts out. My body did not like it at all.
What I learned from that experience is that a 30 minute brisk walk has a deep impact on the body’s internal chemistry.
Walking is the best exercise. Habituate yourself to walk very far. [Thomas Jefferson]