Life Span vs. Life Expectancy

4 Generations: Photo by Jun's World. 

[Edited to add information on Bolivian supercentenarian and link to Helmuth's article.]

It's impossible to know precisely how long you will live. Nevertheless, many seek information on life expectancy so that they can manage their resources.

122 = The maximum human life span.

85 = The average life expectancy for women in the US who reach age 65.

82 = The average life expectancy for men in the US who reach age 65.

77 = The average life expectancy for those in the US measured from birth.

First, it's important to know the difference between life span and life expectancy.

Life span is the maximum number of years that a species can live.  It's the upper limit. For humans, this is 122 years. Jean Calment holds the record for the oldest documented living person. She lived for 122 years and 164 days.  There is some buzz about a man in Bolivia exceeding that record by reaching age 123, but Guinness hasn't verified his documentation yet.

Life expectancy is the statistically expected number of years projected for a person's length of life.

There are a number of factors that influence life expectancy including gender, race, education level, income level, exposure to pollutants, and access to health care including inoculations. Life expectancy is also influenced by lifestyle choices such as diet, exercise and use of cigarettes, alcohol and street drugs.

Life expectancy varies dramatically from person to person, but statisticians and epidemiologists have noted patterns for people who share demographic similarities.

Here in the US, the life expectancy (ALE) in 1900 was about 48 years old.  For a more extensive view of life expectancy and common causes of death, see this article by Laura Helmuth at Slate, which includes an incredible interactive graphic.

It's important to note that this low ALE was due primarily to high infant mortality. People did not drop dead just before turning 50. There were people in prior centuries living to advanced ages. Granted both the raw number and the percentage of older adults was lower than today.

However, ALE was lower "back in the day" primarily due to poor public sanitation, the absence of inoculations, the absence of antibiotics and a general lack of available health care.  Over the last century, health conditions improved, and the ALE has steadily increased. Thankfully, we have improved living conditions, and many have improved preventative health care and improved curative care.

Although not very scientific, there are a number of life expectancy calculators available online.

• Social Security Life Expectancy Calculator
• Northwest Mutual Insurance Life Expectancy Calculator
• University of Pennsylvania Life Expectancy Calculator

If you want to try more calculators, here is a list. Or look at the number of years left remaining--based on age alone--with this tool.

Even if the outcome of an online calculator is not valid, the questions indicate some of the modifiable factors that influence life expectancy.

So do something today to increase your life expectancy and to prepare financially for advanced age. For example, eat some leafy greens, go for a walk, put some money in savings, and wear your seat belt.

Related:

More Seniors than Ever: Population Pyramids
Health Span Differs from Life Span