The lockdown that occurred in the face of COVID-19 brings to light something almost everyone overlooked in the past. We are now an indoor species. This was already true before the lockdown. Outdoor work has declined radically since the Industrial Revolution. In the West today we spend on average over 90% of our lives inside, whether in our homes, offices, schools, hotels or restaurants.
This development is contrary to most of human history, which was spent primarily outdoors. Unknown to most people, the boxes we now occupy have a profound impact on our health and well-being. Our physical and social environments conceivably have as much impact on our health as factors more widely recognized, such as genetics, lifestyle, and behavior patterns. Indoors the elements of air and water quality, lighting, temperature, and acoustics can all have a direct impact on such diverse things as respiration, sleep, immunity, and cardiovascular health.