Throughout human history, the average life expectancy has remained relatively constant, sitting at around 35 years of age. Despite the changes in living conditions, fluctuations from that number were rare. It was only in the 18th Century that this number started to rise with the onset of industrialisation and the Enlightenment.
Since 1920, with the conclusion of the Spanish Flu pandemic, human life expectancy has been on the rise. It was the last major event to have had a negative impact on our life span. Since then, humans have been living longer and growing older on average.
Whereas the average human lived only 41 years in 1920, that number has now doubled to exceed 80 years in 2020.
This astonishing achievement has taken place in the context of a broader narrative of human progress. This story has not been marked by seismic shifts, occurring with fanfare from one day to the next. Instead, we have seen gradual advancements over 100 years, with many going unnoticed or being slowly incorporated into our daily lives without any significant disruption. Some such changes will often require years or decades before their full effects can be seen.
Breakthroughs in medical science, improvements in hospital care, the refinement of public health institutions and systems, and the evolution of new treatments and drugs are all examples of these.
Every one of these developments has kept us safer, prevented us from being exposed to potentially-life threatening diseases, and helped to enhance our average longevity.
In recent research, it has been found that public health reforms at a systemic (legal and administrative) and societal (cultural) level have been instrumental enabling life expectancy to improve so rapidly.
While medical breakthroughs have played a significant part, the author also highlights the role played by activism and social movements, which have led to changes to lifestyles and social norms over time (such as personal hygiene).
Overall, the analysis demonstrates a fascinating change to human health over recent centuries. Take a few minutes to watch the author discuss his research at https://edition.cnn.com/videos/health/2021/05/31/steven-johnson-human-life-expectancy-amanpour-vpx.cnn.