Time Indoors >90% – A Health Crisis

Our species, homo sapiens have roamed the Earth for an estimated 200-300K years. For nearly all of our time on Earth we spent well over 90% of our time outdoors.  In fact, there was no such thing as indoors for >95% of our history. The post-industrial era in which we now live accounts for only ~0.2% of our existence as a species. During that time, we’ve increasingly spent more time indoors. Today, according to US government statistics, we spend 90% of our time indoors.

Time Indoors Leads to Nature Deficit Disorder

 Ever heard of Nature Deficient Disorder? It is not a diagnosis that is officially recognized by the medical establishment but no doubt it has a real impact on our health. As you might imagine, all that time indoors does wonders to our physical AND mental health. See for yourself:

Rates of depression are rising over time and especially for teens and young adults.

Homo sapiens evolved in and are best suited to living in natural environments. As we make our environments increasingly artificial it takes a toll on our health. Numerous studies have shown a host of benefits to spending time in natural settings: it boosts immunity, improves memory, cognitive flexibility, attentional control, emotional well-being, mood, social interactions, and reduced mental distress. Similarly a lack of nature predisposes us to obesity, poor self esteem, bullying, etc. 

Sadly, as we discussed in a previous post, we’ve largely bulldozed away much of nature around our homes to make way for driveways and paved roads built to every single house.  Instead of open fields where our children used to be able to run and play, we’ve cleared away nature in the spaces we spend most of our time.  All this in the name of “progress” and convenience.

In combination with the fact that our children’s pre-frontal cortex is still developing, access to addictively highly pleasurable technology, and the economic incentive to reward companies that can get people hooked on their addictive products – we see the results in the graph above.  We’re increasingly isolated though it’s like suffering from starvation in the midst of plenty.  While the outdoors is no further than a few steps away for nearly everyone, the average teen spends over 8.5 hours in front of a screen (~7.5 hours pre-pandemic).


Our Biology is in Conflict with Modern Life

Here’s the problem: Our biology is in conflict with our daily living. Consider this little thought experiment.  Confine a wild animal (deer, rabbit, lion, shark, your choice) into a relatively small living space.  Keep them almost completely sedentary.  Place artificial lights around them. Now evaluate their mental status.  I don’t know how common depression is among wild animals but I would bet it is much less common than among humans.  Why so?  It’s not because they cannot become depressed (animals confined in cages are often depressed).  It’s because wild animals by definition do not live in those types of environments.  To the extent we see mental illness in animals, not infrequently humans are to blame (such as when we hold them in captivity).  

Here’s a little secret: we humans are natural beings.  We are not made to spend nearly all our time indoors.  Add in processed foods, stress, confined living spaces and poor sleep and you have the recipe for the rise of all sorts of pathology our ancestors never imagined possible for us, their children.


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