The Evolution of Human Life Expectancy

Marcelo Serafim
Oct 2
4 min read

1. Prehistoric Times

In prehistoric societies, human life expectancy was extremely low. On average, people rarely lived beyond 30 years of age. High infant mortality, lack of medical knowledge, frequent accidents, and exposure to predators and harsh environments contributed to this short lifespan. Surviving childhood was itself a remarkable achievement.

2. Ancient Civilizations

In ancient Egypt, Greece, and Rome, life expectancy remained low, typically around 30–35 years. However, those who survived early childhood and avoided war or disease could live into their 50s or 60s. The development of agriculture brought more stable food supplies but also introduced new health challenges, such as malnutrition and the spread of infectious diseases in crowded settlements.

3. The Middle Ages

During the Middle Ages, life expectancy stagnated or even declined in some areas due to famine, poor sanitation, and recurring plagues. The Black Death in the 14th century, for example, killed millions across Europe and reduced average life expectancy drastically. Lack of medical understanding and reliance on superstition limited progress in healthcare.

4. The Renaissance and Early Modern Period

By the 16th and 17th centuries, modest improvements occurred in diet, urban planning, and hygiene, though epidemics such as smallpox and tuberculosis still ravaged populations. Life expectancy hovered around 35–40 years. However, the seeds of scientific medicine were planted during this period, paving the way for future advancements.

5. The 18th and 19th Centuries

With the Agricultural Revolution and the Industrial Revolution, living standards improved for some but worsened for others due to overcrowded cities and poor working conditions. Still, public health reforms, including sewage systems and vaccination campaigns, began to reduce mortality. By the late 19th century, life expectancy in developed countries had risen to about 45 years.

6. The Discovery of Germ Theory and Antibiotics

One of the greatest leaps in life expectancy came with the acceptance of germ theory in the late 19th century and the discovery of antibiotics in the 20th century. Penicillin, introduced in the 1940s, dramatically reduced deaths from infections that were once fatal. Coupled with vaccination programs, these developments saved millions of lives.

7. The 20th Century: Medical and Social Progress

The 20th century witnessed massive improvements in healthcare, nutrition, sanitation, and working conditions. Declines in infant mortality, better maternal care, and new medical technologies such as X-rays and surgeries further extended life expectancy. By the mid-20th century, many countries reported averages of 60–70 years.

8. Lifestyle Changes and Preventive Medicine

By the late 20th century, focus shifted from merely curing diseases to preventing them. Health campaigns against smoking, promotion of physical exercise, and dietary guidelines played a role in extending healthy life. However, new challenges emerged, including heart disease, diabetes, and cancer, which were often linked to modern lifestyles.

9. The 21st Century

Today, global average life expectancy is over 70 years, with many developed countries reaching averages of 80 years or more. Advances in genetics, biotechnology, and personalized medicine hold promise for further increases. At the same time, issues such as obesity, pollution, and antibiotic resistance remind us that progress is never guaranteed.

10. Looking Ahead

The story of human life expectancy is one of resilience, innovation, and adaptation. While prehistoric humans struggled against natural hazards, modern humans face the challenges of managing long lives with chronic diseases. Future improvements may depend on balancing medical advances with healthier lifestyles and equitable access to healthcare.

Questions

What were the main factors that kept life expectancy low in prehistoric times?
How did the Agricultural Revolution influence human health and longevity?
Why was the discovery of antibiotics such a turning point in human life expectancy?
What role did lifestyle changes in the 20th century play in extending life expectancy?
What challenges does modern society face in further increasing life expectancy?

Vocabulary

Mortality – the state of being subject to death.
Epidemic – a sudden outbreak of a disease affecting many people at once.
Sanitation – measures to protect health by ensuring cleanliness.
Superstition – a belief not based on reason or scientific knowledge.
Agricultural Revolution – the period of major agricultural change in the 18th century.
Overcrowded – filled with too many people in a limited space.
Vaccination – treatment that provides immunity against a disease.
Antibiotic Resistance – when bacteria no longer respond to antibiotics.
Chronic Disease – a long-lasting condition such as diabetes or heart disease.
Equitable – fair and impartial, especially regarding access to resources.

Phrasal Verb

Carry out – to perform or complete a task, duty, or action.

Example 1: Scientists carried out experiments to test the new vaccine.
Example 2: Governments must carry out public health campaigns to prevent disease.

American Idiom

An apple a day keeps the doctor away – eating healthy food regularly can prevent illness.

Example: She eats fresh fruit every morning because she believes that an apple a day keeps the doctor away.

English Grammar Tip

Use of “By + Time” to Show Change Over TimeWhen describing improvements in life expectancy, we often use “by” to show when a change was achieved.

Example: By the 19th century, life expectancy had risen to about 45 years.
Example: By the mid-20th century, many countries reported averages of 60–70 years.