Apparently hiking in natural space is superior to walking in urban space -- and presumably also to trudging on the treadmill -- for breaking cycles of negative thinking characteristic of depression.

Here is the original paper, from the _Proceedings of the National Academy of Sciences_:

http://www.pnas.org/content/early/2015/06/23/1510459112.abstract

Will any non-urban outdoor walking do or is there something specific about hiking?

Examples of rumination include spending a lot of time thinking back over embarrassing or disappointing moments, or rehashing recent things you've said or done.

To see how a walk in nature affects ruminative thought, the researchers randomly assigned 38 volunteers with no history of mental illness to take a 90-minute walk in an urban green space near Palo Alto or a loud, busy street with three to four lanes of traffic in each direction.

...

The researchers found that those who went on the nature walk showed reductions in both self-reported rumination and in the profusion of blood flow to the subgenual prefontal cortex. They observed no significant changes in the urban walkers.

Hiking is just walking while wearing something green!

I like that definition of hiking. :)

Isn't hiking walking while seeing something green?? I'll put back on my St Patrick's glasses and be perfect :-)

It's all brown out there now! But still beautiful...