Walking benefits not to be confused with low-intensity cardio

Walking has tremendous benefits but is not to be confused with low-intensity cardio. They are very different.

Key point: If your body isn't designed for low-intensity cardio (long runs, marathons, endurance cycling, etc.), you should not simply throw out the idea of walking as if walking is just another form of endurance cardio. It is not.

Walking is walking. It is not really "cardio" at all, it's just walking--and that's OK. True "cardio" is exercise that raises your heart rate significantly. Walking does not. (unless you are "power walking" which is a different topic). Low-intensity cardio, on the other hand, is basically the long, slow running of the type that marathon runners do, what we might call slow jogging.

So yes, walking is low-intensity, but no, it is not cardio.

Walking is vital despite not being cardio
Walking has tremendous benefits but they are not really due to the raising of heart rate. The benefits of walking include a wide range:
-simply not being sedentary i.e. sitting/lying
-triggers anti-inflammatory shifts in the body
-triggers the body's "motion sensors" to sense it is on the move and hence needs to shed weight
-circulation
-highest
and the list goes on -- see Top 10 benefits of walking
http://www.sharecare.com/health/walking/article/walking-benefits

Low-intensity cardio results in problems that walking does not
Low intensity cardio...
-depletes glycogen (sugar) stores fast; walking does not
-puts a pounding on joints and feet; walking does not
-is not really an option for athletes with mostly fast-twitch muscle; they are just not built for it and their muscles will hit a wall pretty quick.

If your body is designed for marathon running, sure go for it. Those who are designed for endurance tend to have stronger tendons and simply have much more endurance muscle.

But for those who aren't, the idea is that they can still do lots of walking without getting into long running.

So should fast-twitch people do cardio?
Of course. Again, cardio is just any exercise that raises your heart rate. You you probably already do this. If you do a set of pushups and end up panting at the end, that is cardio. If you lift many sets in succession and are breathing heavily throughout, that is cardio--intense cardio.

Some people seem to be designed for high-intensity cardio, others for low-intensity cardio. That's fine, figure out what you are designed to do and do it.

But in either case, walking is still vital.