How Has Average Life Expectancy Changed From the 1800s to Today?

In 2022, the average life expectancy in the United States was 78 years (75 years for males and 80 years for females). That’s a big jump from 1900, when the average life expectancy for a newborn in the U.S. was 47 years.

Lower child mortality rates and medical advances that help prevent the spread of diseases, such as vaccines, have helped contribute to longer life expectancy. Even so, with longer lifespans come newer challenges—like cancers and Alzheimer’s disease—that limit how long the population at large can expect to live.

Prehistoric Life Expectancy

Until fairly recently, little information existed about how long prehistoric people lived. Having access to too few fossilized human remains has made it difficult for historians to estimate the demographics (statistical characteristics) of these populations.

Research suggests that the average life expectancy of Paleolithic-era people (12,000 years ago and earlier) was around 33 years.

In 2006, scientists at Central Michigan University and the University of California, Riverside, chose to analyze what is known as the “relative age” of fossilized skeletons found in archeological digs throughout Africa, Europe, and elsewhere.

Relative age is the comparison of one fossil to another fossil to determine which is younger or older. Using carbon dating and other techniques, scientists can estimate how long two individuals living in the same time period may have survived.

After comparing the proportion of those who died at a younger age to those who died at an older age, the researcher concluded that longevity only began to significantly increase—past the age of 30 or so—about 30,000 years ago.

In a later article published in Scientific American, the researchers called the shift the “Evolution of Grandparents,” marking the first time in human history that three generations may have co-existed.

Ancient Times Through Pre-Industrial Times

Life expectancy estimates from ancient to pre-industrial times haven’t changed all that much from the Paleolithic era. Though evidence in the form of historical records or fossilized remains is limited, the body of research suggests that life expectancy rates stagnated from the Neolithic era to the dawn of the Industrial Age.

Scientists note that the main factors limiting life expectancy were infant deaths and early deaths caused by malnutrition or disease. This included pandemics like the bubonic plague of the 14th century that spread throughout Europe and Asia, killing more than a third of Europe’s population.

Similar losses were attributed to smallpox, which resulted in pandemics during the 11th century (attributed to the Crusades) and the 17th century (due to the immigration of European settlers into North America).

Widespread poverty also led to malnutrition and early death in ancient times in the same way as it does today.

Here is a short breakdown of average life expectancy from ancient times to the mid-18th century:

1800s to Today

From the 1500s until around the early-1800s, life expectancy throughout Europe hovered between 30 and 40 years. This was due in part to infant mortality rates that remained at 25% until 1800.

However, from the mid-1800s onward, estimated life expectancy at birth doubled every 10 generations due to improved health care, sanitation, immunizations, access to clean water, and better nutrition.

Even so, diseases like rheumatic fever, typhoid, and scarlet fever still impacted life expectancy during the 1800s and early 1900s. But as science progressed and newly created vaccines offered protection against many of these and other illnesses, life expectancy began to rapidly increase.

An example of this was offered by Scottish researcher T.H. Hollingworth, who described the life expectancy of women at age 15 from pre-industrial times to modern times.

Today, more than half the world’s countries boast life expectancy figures of more than 75 years, according to data compiled by the Central Intelligence Agency.

Today and the Future

However, the life expectancy path is always upward. In the same way that the Black Plague reversed life expectancy gains during the 14th century, pandemic diseases like COVID-19 have done the same in the 20th century. Other factors like drug overdose, suicide, homicide, and heart disease have also had an impact.

According to the Centers for Disease Control and Prevention (CDC), life expectancy in the United States declined two years in a row from 79 years in 2019 to 77 years in 2020 to 76.1 years in 2021. It was the biggest two-year decline in life expectancy since the years 1921 to 1923.

The decline was largely driven by the COVID-19 pandemic, which accounted for 74% of the decline from 2019 to 2020 and 50% of the decline from 2020 to 2021.

Other researchers predict that lifestyle factors like obesity may halt or even reverse the rise in life expectancy.

Epidemiologist S. Jay Olshanky warns that in the United States—where two-thirds of the population is overweight or obese—complications like heart disease and type 2 diabetes could very well reverse gains made in the first half of the 21st century.

At the same time, increasing life expectancy in developed countries like the United States may bring both good and bad news. In short, by living longer, people are at greater risk of dying from aging-related illnesses like coronary artery disease, certain cancers, and Alzheimer’s disease. Until cures are found, these conditions could very well create a “glass ceiling” for how long a person can possibly live.

Even, many of these aging-related conditions can be prevented or delayed through lifestyle choices such as maintaining a healthy weight, exercising regularly, managing stress, and eating a healthy diet (such as the Mediterranean diet and anti-aging diet).

Summary

Life expectancy has improved considerably since the 1800s, largely due to improvements in infant mortality and public health measures such as vaccines.

In 1900, life expectancy was only around 47 years. Today, the average life expectancy for someone living in the United States is around 78 years. This is a vast improvement over the average life expectancy for someone living in prehistoric times, which was only around 30.