In 1900, life expectancy in the United States was 47.3 years; in 2017, it was 78.6. Here’s why the numbers have gone up, plus advice from medical experts on how to add more healthy years to your own life.
Have you ever wondered how old you’ll be when you die? Even if it was just to estimate how much you should put away in your 401(k) or how much time you have to pay off your student loans?
Life expectancy represents the average number of years that someone can expect to live depending on the year they were born. For anyone born in the United States in 2017, life expectancy is 78.6 years, according to the Centers for Disease Control and Prevention (CDC).
Another way that experts measure life expectancy involves considering the percentage of people who live to specified ages. Using that approach, in 2017 nearly 25 out of 100 people in the United States lived to celebrate their 90th birthday, according to the CDC.
Both those calculations are based on averages of the entire population and include all sexes, races, and parts of the country. How long each individual lives is determined by many factors, says Qi Sun, MD, a doctor of science and an associate professor at the Harvard T.H. Chan School of Public Health. He explains that life expectancy is influenced by genes, environment, and lifestyle choices: “We can look at how the life span has increased over the last 100 years and see that it’s modifiable,” he says.
Read on for commonly asked questions about life expectancy and what you can do to live longer and healthier.
Do the ages that my parents or grandparents died make a difference in figuring out my life expectancy?
Family history is a big predictor of longevity. “If you look at parents’ life span and compare it with their offsprings’, you’ll find certain correlations because sometimes they share the same genes,” says Dr. Sun. If some of those genes lead to certain diseases, it may shorten life span. “On the other hand,” he adds, “families that have good genes may live longer.”
Some similarities in health patterns that may seem genetic could also be due to common habits and location. Family members often share the same environment, especially when children are young and still live at home. “Families eat a similar diet and have the same access to medical care, which are both factors that impact longevity,” Sun says.
You just need to look at data from 100 years ago and compare it with current life expectancy to see that there’s more to longevity than simply genetics. According to the CDC, the life expectancy of someone who was born in 1900 was only 47.3 years.
“Genetics wouldn’t really explain this jump,” Sun says, adding that a lot of things combined to cause this increase, including improved medical care and hygiene.
Why do women live longer than men?
Women tend to live longer than men, and that’s been the case for at least the past century, says Robert Anderson, PhD, chief of the mortality statistics branch of the CDC. “Before that, a very high maternal mortality pulled down the average life expectancy for women,” he says.
Ever since medical improvements led to a huge decrease in the number of women dying during childbirth, life expectancy for women has gone up. According to the latest CDC data, women in the United States live close to five years longer than men, on average. “Some experts argue that there’s a genetic component, while others theorize that it has to do with differences in risk-taking,” says Dr. Anderson.
Why do some races have a shorter life expectancy?
On average, black Americans have a shorter life expectancy than white Americans, and Hispanic people living in the United States have the longest life span of all three groups. About 76 out 100 Hispanic Americans will live until at least 75 years of age, compared with about 70 white Americans and approximately 60 black Americans.
It’s not clear why black Americans die sooner. “We haven’t identified any real genetic component that would cause this difference,” says Anderson. It could be due to culture and diet, and there may be significant environmental factors that contribute.
As a group, a higher percentage of black Americans have heart disease than white Americans, according to the American Heart Association. Although the gap in life expectancy between the black and white population has begun to close — it decreased by 2.3 years from 1999 to 2013, according to the CDC — it still exists. Stress, more limited access to health care, and cultural factors all play a role, says Anderson.
Hispanic Americans may have the longest life span because they are less likely to die from a number of health conditions, including cancer, heart disease, chronic lower respiratory diseases, stroke, diabetes, and suicide, according to the CDC.
Is U.S. life expectancy increasing?
The long-term increase in life expectancy over the past century is largely due to two factors. “From 1900 until 1950 and then from 1950 to 2000, there was a fairly dramatic increase in life expectancy, primarily due to control of infectious diseases,” says Anderson, citing significant discoveries in antibiotics and vaccines and improvements in sanitation.
Since 1950, gains in longevity are mostly due to advances in the prevention and treatment of chronic diseases, mainly heart disease and stroke. “There’s also been an improvement in the cancer death rates beginning in the mid-1990s,” Anderson says. Cardiovascular disease and cancer are the two leading causes of death in the United States, accounting for about 40 percent of total deaths.
Life expectancy has actually declined slightly over the past three years, according to the CDC. Although the CDC says the trend is largely driven by drug overdose and suicide, there is another, more significant factor: the obesity epidemic.
“I think it’s fair to say that we are already seeing the impact of obesity on life expectancy,” Sun says. “A lot of people out there blamed the opioid crisis or drug overdose for the decrease in life expectancy, but the obesity problem is much bigger.”
What are the most important factors that determine how long you live?
“Basically any factor that influences mortality also contributes to life expectancy, because mortality is how life expectancy is calculated,” says Sun. Blood pressure, cholesterol levels, body mass index, and diabetes are established risk factors for chronic diseases like heart disease and stroke, and people who have those diseases have a shorter life expectancy.
Okay, I haven’t had the healthiest lifestyle, and now I’m over 50. Am I doomed?
“It’s never too late to adopt a healthier lifestyle,” says Sun. If a person has spent decades eating an unhealthy diet or being physically inactive, they may or may not have developed certain chronic conditions like diabetes or heart disease. Still, “If those individuals move their diet and exercise habits from the unhealthier end of the spectrum to the healthier side, they can improve their life span,” Sun says. “Just follow common sense: no smoking, avoid alcohol or drug abuse, eat a healthy diet, engage in physical activity, and try to stay positive and optimistic.”
If you need more incentive to make lifestyle changes, consider this: Research shows that older adults are enjoying themselves more than just about everyone else. According to a survey of 1,546 Californians ages 21 to 99, people in their nineties were the most content. The research, published in August 2016 in The Journal of Clinical Psychiatry, found that older people were happier and less depressed, and had less anxiety than younger people.
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