I heard about a very fit aboriginal tribe that reported zero cases of depression. The anthropologist initially hypothesized that personal fitness was warding off the doldrums. But it turned out that none of them had ever heard of exercise. They scoffed at the idea that people would run or lift things for no reason other than to stay in shape.

The body might be better off after exertion, but running for no reason can exasperate the brain: "Why are we doing this? Where are we going? This makes no sense! You fool!"

He concluded that they had no depression because they did everything for each other. Competition and self-reliance are trivial, nonproductive, illogical. Homo sapiens have an innate need to seek connection via a deep, mutual dependency. Industrial society has estranged us from this fundamental need to be an integral part of each other's lives. We need to live life with purpose to achieve the connections that relegate sadness to the back burner or abolish it altogether. Treadmills, rowing machines, free wieghts, jogging with no imperative - they're all useless activities that by their very nature are limited and unworthy of your time. Unfortunately, humans are now almost universally sedentary, living separately and struggling with incredible rates of depression.
I have no conclusion or recommendation other than the observation that we've painted ourselves into a corner and will be better off once we've spent all the fuel and let go of the false promises of progress and technology.

Sorry about the blog post as comment. I'll shut up for a while.