What Is Life Expectancy?

GettyImages-1355493845 You may have come across the term life expectancy in books or news briefs. But what does life expectancy mean, and how does it affect you?

Life expectancy is an estimate of how long you can expect to live. It does not dictate how long you will live—you can have a say in your lifespan. And lifestyle and diet modifications can help you slow aging to extend your lifespan so you can surpass your life expectancy at birth.

Here’s what you need to know about life expectancy and how to prolong your lifespan.

What is life expectancy?

Life expectancy is the average number of years you can expect to live based on the year you were born and other demographic factors. Life expectancy is an estimate; just because you can live to a certain age does not mean you will live to or surpass that age. [1,2]

How is life expectancy measured?

Life expectancy is measured using life tables, which show the probability of someone dying before their next birthday. [3]

Life tables reveal changes in life expectancy over time. [2]

Cohort life tables or expectancy

Cohort life expectancy (CLE) shows mortality (deaths) for a certain birth year. It measures how long people born in the same period actually lived. [4]

Period life expectancy

Period life expectancy (PLE) represents the average number of years a baby born in a particular year could expect to live, assuming that the death rates for that year remain constant. [4]

Put differently, PLE estimates what would happen to a group of people if the same mortality conditions that existed at birth continued throughout their lives. [5]

It is hypothetical: If death rates decline, then PLE would underestimate life duration, whereas if death rates increase, then PLE would overestimate how long that group of people will live.

Unlike CLE, which only reflects past deaths, PLE shows the most current death rates across all ages. PLE can estimate how many more years a group of people at a specific age (birth to 100 or more) can expect to live, provided mortality patterns of a given year remain the same throughout the rest of their lives. [2,4]

Life expectancy estimates by country

Life expectancy varies across the world and depends on environmental, societal, and lifestyle factors. Below are data on life expectancies for different countries as of the year 2020. [1]

Switzerland: 83.0 years
New Zealand: 82.3 years
Israel: 82.0 years
Canada: 81.4 years
Germany: 81.2 years
Taiwan: 81.1 years
United Kingdom: 80.5 years
United States: 77.0 years

What impacts life expectancy and how long you’re expected to live?

Race and ethnicity

There are racial and ethnic differences in life expectancy, and data reveal black Americans have a lower life expectancy than white Americans, and that American Indian and Alaska Native peoples have the lowest life expectancy of people living in the United States.

Multiple factors influence these racial differences including socioeconomic factors (discussed in more detail below), access to health care, work environment/occupational risks, and social support. [1]

Sex

Women have a longer life expectancy than men. In the United States, the life expectancy of women is 79.1 years compared to 73.2 years for men. [6] Many factors influence this difference.

Females have more health issues throughout their lifespan, whereas males experience more life-threatening conditions. [7] Men tend to smoke more than women, and smoking correlates with higher mortality. [8]

Socioeconomic status

Factors influencing socioeconomic status—such as education, job, and wages—also affect life expectancy.

In one study of people in the United Kingdom, researchers found a seven-year difference in life expectancy between groups of those with no educational qualifications and those with some level of education.

Socioeconomic status and demographics also impact health inequalities, further contributing to differences in lifespan. [9]

The pandemic has recently decreased global life expectancies

Globally, life expectancy has decreased since 2019 due to the COVID-19 pandemic. National life expectancy in the United States, average life expectancy dropped by 2.7 years from 2019 to 2021. [6]

While life expectancy estimates in many parts of the world, including the US, are still below pre-pandemic levels, some countries have been able to bounce back—in many Western European countries, life expectancy has almost returned to pre-pandemic age. [10]

Can life expectancy age estimates change?

Life expectancy can change throughout your life.

Over time, life expectancy has steadily increased due to medical advances that have reduced mortality rates and shifts in environmental and lifestyle habits. [11]

Life expectancy can also be calculated as the average number of years of life remaining for a person based on a given age.

For example, the life expectancy at birth for someone born in 1950 was 68.2 years. If that person lived to 65 years (in 2010), life expectancy became 87.3 years.

In other words, that person could expect to live 19.1 more years than was initially estimated in the life expectancy at birth. [12]

What’s the difference between life expectancy and lifespan?

Life expectancy and lifespan are often used interchangeably, but these terms differ slightly.

Life expectancy is an estimate; it is the average number of years you can expect to live.

Lifespan either refers to how many years a person actually lives or the number of years you can live, based on the years the longest-living person was alive. [11]

What can you do to improve health, slow aging, and extend lifespan?

Many factors affecting life expectancy (such as demographics) are out of your control. But, you can influence lifespan by prioritizing healthy behaviors that slow aging.

Quit smoking: Smoking is one of the main factors of mortality and a shorter lifespan, as it is a significant contributor to chronic diseases. Those who have never smoked and former smokers are more likely to age healthily than current smokers. Moreover, quitting smoking—even at 60—can extend life expectancy. [13]

Minimize exposure to pollution: Ambient air pollution contributes to loss of life expectancy and deaths through its association with cardiovascular disease and other chronic conditions. Where you live plays a big role in how much pollution you’re exposed to daily from vehicle emissions, fuel and gas used to heat homes, manufacturing facilities, and power generating plants. And while changing where you live isn’t necessarily a practical solution, it’s important to pay attention to air daily air quality ratings and limit time outdoors on high air pollution days. [14,15]

Moderate alcohol consumption: Moderate alcohol consumption is correlated with healthy aging and may benefit life expectancy. What constitutes moderate alcohol intake varies, but recommendations are not to exceed more than 14 drinks a week. [16,17]

Limit red meat: A high intake of red meat is associated with reduced life expectancy. One prospective cohort study found a 13% higher risk of death in participants who ate at least half a serving (1.5 ounces) or more of unprocessed red meat per week than those who consumed one serving (3 ounces) or less per week. [18,19]

Key takeaways

Life expectancy is how long you can expect to live, whereas lifespan is how long you can live.
You can surpass estimates for life expectancy at birth. Medical advances and environmental factors contribute to changes in life expectancy.
Slow aging and extend lifespan through lifestyle changes, including decreasing or quitting smoking, reducing red meat intake, drinking alcohol in moderation, and limiting exposure to air pollution.

References:

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9008499/

[2] https://www.cdc.gov/nchs/nvss/life-expectancy.htm#publications

[3]https://cdn.who.int/media/docs/default-source/gho-documents/global-health-estimates/ghe2019_life-table-methods.pdf?sfvrsn=c433c229_5

[4] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7026938/

[5] https://www.cdc.gov/nchs/data/nvsr/nvsr71/nvsr71-02.pdf

[6] https://www.cdc.gov/nchs/pressroom/nchs_press_releases/2022/20220831.htm

[7] https://link.springer.com/article/10.1007/s10654-014-9893-4

[8] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8096404/

[9] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8131985/

[10] https://www.nature.com/articles/s41562-022-01450-3#Sec16

[11] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4861644/