By Melissa Tennen, HealthAtoZ writer
Better heart disease care, a little less smoking, and a little more exercise have helped continue the century-long upward trend of life expectancy in the United States, according to the U.S. Department of Health and Human Services.
The average life span for an American was 77.3 years in 2002, up from 77.0 in 2000. In fact, Americans' health in the past 50 years has improved dramatically. During the past half century, death rates among children and adults younger than 24 were cut in half. And adults ages 25 to 64 fell nearly as much. And those 65 and older dropped by more than a third.
In the 2001 study, every age group saw record highs. For men, life expectancy increased from 74.3 years in 2000 to 74.4. For women, life expectancy increased from 79.7 years to 79.8. By contrast, life expectancy in 1900 was 48.3 years for women and 46.3 years for men.
"We have improved health care and have a somewhat declining rate of smoking. And there is some evidence that Americans are exercising more," says Alvin Mushlin, M.D., Sc.M., professor in the department of public health at Weill Medical College of Cornell University in New York. "A primary reason is a decrease in heart disease mortality."
Life expectancy measures the overall health of a population. Improvements in nutrition, housing and hygiene contribute to longer lives, notes Robert Anderson, Ph.D., lead statistician in mortality statistics branch for the Centers for Disease Control and Prevention.
"In the early 1900s, we saw a rapid rise of life expectancy because of dramatic improvements in mortality at the younger ages," Anderson says. "If we save a 1-year-old child, he or she could contribute 70 or more years. In the later part of the 20th century, life expectancy has risen more slowly because improvements have been predominantly at the older ages. If we can prevent a 70-year-old from dying, he or she might contribute another 5 or 10 years to the average life. Life expectancy is all about averages."
Better control of deadly infectious diseases such as polio and influenza is reflected in a sharp rise in the first half of the 20th century, Anderson says. Fewer people were dying in childhood, meaning more people could expect to live longer lives. After 1950, life expectancy at age 65 improved mostly because of better access to health care, advances in medicine and healthier lifestyles.
The rate of increase has been less dramatic since the 1960s. Now we are focused on dealing more with chronic and complex conditions such as diabetes and heart disease that can be controlled or sometimes even reversed with medication, diet and exercise, Anderson says.
Of course, that gap closes as an American ages; chronic diseases such as heart disease replace the risks from dying by homicide, suicide and injury that are major causes of death for younger people.
"Good things are outweighing the bad. It's not only better treatment but better prevention," Mushlin says.
Since 1999, the five leading causes of death were related to either injury or chronic disease among children and people younger than 24. In 1950, in contrast, two of the five leading causes of death were infectious disease such as influenza and tuberculosis. For other age groups and populations, heart disease and cancer are the top killers. Heart disease is the number one killer, ending the lives of at least 950,000 Americans each year. Cancer ranks second, killing at least 570,000 each year, according to the Centers for Disease Control and Prevention.
Medical technology and research are improving. That means less invasive surgeries, better and more diverse medication options, and increasing evidence about how to determine risk for diseases such as cancer and heart disease. And scientists are also learning how to prevent chronic disease and conditions.
"Determining life expectancy is not an exact science. We will probably continue to see changes," Anderson says, noting that even if we found a cure for cancer, it doesn't mean immortality. "We all have to die of something."
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External Sources
 | The Centers for Disease Control and Prevention
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| The Department of Public Health at Weill Medical College of Cornell University in New York
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This article was reviewed and updated June 2007.
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