For the sake of our health, we need to kick the indoor habit

As a species we need to get out more. Humans now spend so much time indoors that many of us are cultivating a variety of serious health complaints, and for some they could be fatal. It is not so much that outdoor time is inherently good; more that our bodies are built to anticipate it and the way we live now is confusing to our systems. Nearly two decades ago a study published in Nature magazine concluded that the average American spent 93% of their time indoors. And that was before tablets and smartphones.

In trying to cope with the shaded, sedentary world we have made, our bodies wage war on what should be harmless antigens; they fail to make bones strong enough to support our weight; even our eyes struggle to focus without the help of lenses. This incremental creep across the threshold to the great indoors began tens of thousands of years ago when the first settled communities emerged.