How 'natural' is running as exercise?

A simple question, but with a very complex answer! Science indicates that humans evolved as running bipeds. That is, we are built for two legged locomotion and we were "Born to run", which happens to be the title of an interesting new book by Christopher McDougall. (If you click this link you will see there has been a lot of other publication activity around this topic as well!)
The complication comes in several forms:

• Some humans still have a body shape that if well adapted to this original type of long distance running.
• Other human groups have adapted over thousands of years to non-running lifestyles (e.g sherpas of Nepal)

In other words, even though there is only one human species; we have adapted and changed our bodies over thousands of years to suit different environments.
Just as humans have bred hundreds of types of dogs, of vastly different body sizes and shapes (over a very short time period) so nature has bred many different body types to suit the vast range of human habitats. Modern mobility dulls our appreciation of the very distinctive racial and tribal types that originally inhabited each place, each adapted to their climate and lifestyle.
My point is this: we don't expect a bulldog to outrun a greyhound. Likewise, we should not be surprised that Kenyans and Ethiopians  are the best distance runners.
What does this mean to you?
Well, depending on your body type, maybe running is not the BEST exercise your you (or maybe it is!)
I am not saying this because I am against running; I am not and have been a runner all my life - but I DO have the body type that is ideal for running  -lean and light boned.
Weight bearing exercice is essential for your health, but a large volume of running only suits a certain proportion of the population.
Have a good think about your body type. It may be that another type of exercise would be your best option for developing base fitness - cycling, rowing, swimming - there are many options.
The real question is: Do I WANT to run?
If you want to run, you SHOULD run - even if you think you are the "wrong" build!
My next post: How can I run if I am the not built for it?