Unless you are elderly or morbidly obese, walking falls into the category of what I like to call “physical activity”–it’s not a workout.
It’s certainly better for your body than lying on the couch (or slumping over at a desk–sit up straight!), but it doesn’t meet my standards of true exercise.
As far as I am concerned, in order for something to count as a workout there are three basic requirements: elevated heart rate, muscle fatigue, and sweat. Power-walking might fulfill these requirements, but for the average person, just taking a stroll ain’t gonna do it.
Don’t get me wrong, walking is great physical activity and most Americans probably ought to be doing a lot more of it. As a New York City resident, I walk just about everywhere. (I just don’t kid myself into thinking that it’s a workout!)
Walking can definitely add up over the course of the day, leading to weight loss, which is probably part of the reason why New Yorkers tend to be slimmer than most Americans–so I encourage you to walk as much as possible. Everybody should be getting at least an hour or two of daily physical activity. It’s just that you should also do some real workouts.