I’ve lived in a lot of places in my life, and spent at least some time in seclusion in each one. And I have experienced the “cabin fever” feeling before... but not everywhere I’ve lived. In some environments, it happened easily and immediately; in others, it never did. I’ve tried to think about my environment at each juncture to figure out if the situations where I did experience “cabin fever” had anything in common.

Every time I experienced the symptoms described in the article (restlessness, lightheadedness, insomnia, irritability, etc.) I was living in a modern, rather-well-sealed apartment building; or was on a long road-trip in a modern, rather-well-sealed car; or was on a long plane flight; or was staying in a modern hotel room in a high-rise; or I was camping in a tent or camper-trailer.

Meanwhile, I’ve never experienced these symptoms while living in an old, drafty brick building (repurposed office building); or while living in a Victorian-era farmhouse; or while staying in a low-rent motel; or while camping under the stars.

My conclusion is that “cabin fever” is a feeling you get when your living space is not well-ventilated. Specifically, when there’s no way to create a through-draft of air, so even opening windows won’t force out the air deeper in the home—leading to that air becoming stale, creating a built-up “cloud” of CO2, other gaseous bodily wastes, and exhaled aerosolized water droplets (you know, those things that viruses travel on.) It happens faster when more people are cooped up together in a small space, because this cloud of stale air gets denser, faster; and because there’s less time when everyone is gone at once, where the air can “recharge” by slow through-insulation-barrier gas exchange.

If the problem is stale air, then just “going outside” is only a temporary fix, because the air will usually be just as stuffy when you return (unless you leave for hours and leave your windows open and fans on.) On the other hand, you can be fine while inside indefinitely, if you open a window and then sit right beside it, where the outside air can reach you. But this will only work if there’s enough wind to push the air into the house a small bit; and it seemingly has no effect—possibly for purely-psychological reasons?—if the air outside is humid, as it is in e.g. Hong Kong. (But going outside in humid places still works for temporary relief. Weird.)

And that last realization leads me to the secondary conclusion that the (or my, at least) human physiology is responding mainly to aerosolized-moisture-content in the air (in some way that’s distinct from responding to the evaporated humidity) as a proxy metric for the other, harder-to-sense air-quality measures. So, in theory, you might be able to reduce the qualitative of “cabin fever” just by buying a dehumidifier.

But really, I wouldn’t recommend it; there’s pretty good documentation about the subtler, less-self-apparent effects that a high CO2 concentration in a room can have on people, and on how much CO2 does tend to build up in closed or not-well-ventilated rooms—especially people’s bedrooms at night.

Relevant links:

- Tom Scott’s This is Your Brain on Stale Air — https://youtu.be/1Nh_vxpycEA

- https://en.wikipedia.org/wiki/Sick_building_syndrome (when this same thing happens in offices)

- https://en.wikipedia.org/wiki/Feng_shui (which, at its practical core, seems to be about arranging the contents of living spaces to avoid having objects act as baffles to the through-flow of air)