Oliver James Montgomery-What is the average life expectancy? And how to improve your longevity.

While no one expects to live forever,Oliver James Montgomery we're all aware of our own mortality and wonder how long we're likely to be around. Of course, that amount of time has changed significantly over the course of history. Even as recently as the 1700s, the average person worldwide lived only to their 30s, according to a University of Oxford data report.

Comedian Jerry Seinfeld once joked about if such a person existed today, saying, "you'd get your driver's license around 5, you'd marry at 9, divorce at 15, and in your late teens, you'd move down to Florida...and eventually people (would be) saying things about you like 'well, it's amazing, he's 28, but he's still very alert.'" 

Today, a number of factors help explain why we live to be so much longer than we used to - and why we may someday be able to expect to live longer still.

What is the average life expectancy? 

In 2021, the average person could expect to live to be 76.1 years, according to provisional data from the U.S. Centers for Disease Control and Prevention's National Center for Health Statistics. That number was a slight dip from the year before, attributed to increased death rates related to heart disease, chronic liver disease and suicide. 

But life expectancy varies from country to country, and today, the worldwide life expectancy average is 73 years. In some countries, it's higher. "The current life expectancy for someone living United States is 76.4 years for both sexes or 79.3 years for females and 73.5 years for males," says Dr. Julia Adamian, medical director of NYU Langone internal medical associates at NYU Grossman School of Medicine in New York City. 

Why do some people live longer than others? 

These numbers are impacted most commonly by genetics and personal lifestyle factors such as dietary choices and activity levels. Dr. Amit Shah, an internist and geriatrician with Mayo Clinic in Arizona, says that genetics play a major role and that "up to 25% of longevity is genetic." The rest, he says, comes down "to factors that are in our control." 

"Some people are predisposed to diseases like certain cancers or diabetes," echoes Dr. Justin Jones, a primary care physician and Chief Medical Officer at Revere Health in Utah - though he similarly stresses that even such predispositions don't have to be definitive if one takes proper care of themself. 

Socioeconomic status also plays a major role in healthy aging and longevity, with impoverished areas that have limited access to healthcare being the hardest hit. One's social environment factors in as well. "People who live in societies that have the most long-lived individuals (as outlined in the book "Blue Zones" by Dan Buettner), have a high level of social engagement with roles for older individuals to have in the family and society," says Shah. 

This is further evidenced by a remarkable 80-years-in-the-making scientific study on happiness. The Harvard research found that the presence of strong relationships and regular human interaction ends up making a definitive difference in both the quality of one's life and the length of time one can expect to live. 

How to live longer

To live our longest lives, then, it's important to maintain meaningful relationships and feel like our existence matters. "I believe that it is very important to have a purpose in life—whatever that might mean to an individual," says Shah. "As one of my long-lived patients put it, 'doc, you need to have a reason to get up in the morning!'" He says it's also critical to maintain a healthy weight, get regular physical activity, and address cardiac risk factors such as high blood pressure and high cholesterol levels.

What is the Blue Zones diet?How to eat like people who live the longest.

"The best ways to ensure longevity are to adopt healthy habits related to eating patterns and exercise," echoes Jones. Along with making the right dietary choices such as getting plenty of high-fiber foods, lean proteins, whole grains, and lots of fruits and vegetables, he says, it's also important to avoid the foods that are known to cause the most harms such as ultra-processed foods, added sugars, and excessive red meat. Avoiding "modifiable risks" such as tobacco products and limiting alcohol consumption is also recommended. "Finally, don’t underestimate the benefits of consistent preventive care with your doctor, including annual physicals, periodic blood work, and age-appropriate cancer screenings," Jones advises. 

"We are what we eat and drink, how much we move, what we think, our outlook on events, our resilience, and how much we care for each other," says Adamian. "While there is no secret sauce to longevity, these are the main ingredients."