Life Expectancy vs. Lifespan: They're Not the Same Thing
Life Expectancy vs. Lifespan: They're Not the Same Thing
How long do you expect to live?
It's an interesting question. And a pretty common question.
Maybe you have a number in your head. Maybe you don't want to think about it at all.
But several different questions are hiding inside that one question.
How long could a human being live?
How long do people in a particular population actually tend to live?
And perhaps most importantly:
How many of those years can we expect to live in good health?
Those questions bring up three different concepts: lifespan, life expectancy, and healthy life expectancy.
And they aren't the same thing.
Let's Start With Lifespan
Lifespan refers to how long an individual lives. When we talk about the lifespan of humans as a species, we're often talking about the maximum age humans can potentially reach.
There is a big difference between the maximum possible lifespan and the average number of years people live.
Think about it this way.
If one person lives to 100, that doesn't mean the average person lives to 100.
It simply means living to 100 is possible.
The longest-lived people in a population tell us something about the potential limits of human longevity. They don't tell us what the typical experience will be.
And that's where life expectancy comes in.
What Is Life Expectancy?
Life expectancy estimates how many years a person can expect to live based on mortality patterns in a particular population and period.
You will often hear about life expectancy at birth, which estimates the average number of years a newborn could expect to live if the mortality rates observed at that time remained the same throughout that person's life.
And that last part is important.
Life expectancy isn't a crystal ball.
If life expectancy at birth was 75 years in a particular year, that doesn't mean everyone born that year will die at 75. Obviously.
Some will die much younger.
Some will die much older.
And some will live well beyond 100.
The statistic is an average based on mortality patterns.
Why Does Life Expectancy Change?
Life expectancy isn't fixed.
It changes as circumstances change.
Think about someone born in 1949 compared with someone born in 1969 or 1989.
In the United States, life expectancy at birth was approximately:
1949 to 1951: 68.1 years
1969 to 1971: 70.8 years
1989: 75.3 years
That's a pretty substantial difference over just a few decades.
Why?
Because the world changed.
Medical care changed.
Vaccines became more widely available.
Treatment for infections improved.
Infant and childhood mortality declined. In other words, more of us survived childhood.
Emergency medicine improved.
Treatment for heart disease and other chronic conditions improved.
Public health measures changed.
Living conditions changed.
And our understanding of risk factors changed.
But not every change has been positive.
Smoking, obesity, chronic disease, substance use, environmental exposures, socioeconomic conditions, access to healthcare, and other factors can all influence population health and longevity.
And life expectancy doesn't increase in a perfectly straight line.
It can go backward.
The COVID-19 pandemic, for example, caused substantial declines in life expectancy in the United States and many other countries.
So when someone says, "People are living longer than they used to," that's generally true over the long term, but it doesn't mean life expectancy increases every single year.
And Here's Where It Gets Personal
Let's say you were born in 1949.
The life expectancy at birth for the U.S. population around that time was about 68 years.
Does that mean you were supposed to die at 68?
Obviously not.
If you survived childhood and reached adulthood, your individual life expectancy changed.
The same is true for someone born in 1969 or 1989.
The conditions surrounding your birth matter, but so do the conditions throughout your life.
Your age.
Your sex.
Your genetics.
Your environment.
Your access to healthcare.
Your socioeconomic circumstances.
Your behaviors.
Your health conditions.
Your social connections.
All of these things can influence how long you live.
And that's one reason I don't like using population statistics as though they are individual predictions.
They aren't.
Now Let's Talk About Healthy Life Expectancy
Healthspan: a popular term for the years of life spent in relatively good health and functions similarly to the concept of healthy life expectancy, although the technical definitions aren't always identical.
Here's the part I focus on so much more in my work and in my personal life.
Let's say we could tell you with absolute certainty that you'd live to 88.
Would you be satisfied with that number?
Maybe.
But I'd want to know something else.
What are those 88 years going to look like?
Because living to 88 isn't necessarily the same as living well to 88.
You could spend the last 10 or 15 years of your life dealing with significant disease, disability, pain, or limitations. You may need assistance with ADLs (activities of daily living) such as bathing, dressing, eating, and moving between chair, bed, and toilet.
Or you could remain relatively active and independent well into your later years.
That's where healthy life expectancy comes in.
The World Health Organization defines healthy life expectancy, or HALE, as the average number of years a person can expect to live in full health, accounting for years lived in less than full health because of disease or injury.
In other words, we're looking at more than simply how many years.
We're asking about the quality and health of those years.
And that is a very important distinction.
The Goal Isn't to Live in a Bubble
This is where I want to push back on some of the longevity advice that seems to be everywhere right now.
I hear people saying they want to cheat death. Spoiler – they can’t.
Some people want to optimize absolutely everything.
Every bite of food.
Every minute of sleep.
Every workout.
Every supplement.
Every biomarker.
And if that's your thing, fine.
But I don't think healthy aging requires living in a bubble.
You can eat dessert.
You can have a glass of wine.
You can travel.
You can stay up late once in a while.
You can enjoy life.
At the same time, some things clearly aren't doing us any favors.
Smoking.
Excessive alcohol use.
Avoidable drug use.
Driving recklessly.
Ignoring serious symptoms.
Never exercising.
Eating a diet consistently lacking in essential nutrients.
Never getting preventive healthcare.
The goal isn't to eliminate every risk from your life.
That's impossible.
The goal is to balance living well today with supporting your health for tomorrow.
So What Can You Actually Do?
You can't control everything that determines how long you'll live.
But there are things you can do to support your health and increase your chances of spending more of those years in good health.
1. Don't Smoke
If you smoke, quitting is one of the most meaningful things you can do for your health.
And if you don't smoke, don't start.
It's not particularly complicated advice, but it's important.
2. Move Your Body
Regular physical activity supports cardiovascular health, muscle strength, bone health, balance, and physical function.
And as we age, maintaining the ability to get up, walk, carry things, climb stairs, and do those everyday activities becomes increasingly important. That’s mobility.
Exercise isn't just about burning calories.
It's about maintaining your ability to live your life.
3. Eat a Varied Diet
There isn't one longevity diet.
There isn't one magical food.
And you don't need to eat only foods that someone has labeled a "superfood."
Instead, build a varied eating pattern that includes vegetables, fruits, whole grains, beans, nuts, seeds, adequate protein, and other nutrient-rich foods.
Variety gives you a broader range of nutrients and other beneficial food components.
4. Get Enough Protein
Protein becomes particularly important as we get older because maintaining muscle mass and strength is key to physical function.
That doesn't mean you need to live on protein shakes or buy into all the protein, protein, protein marketing.
It means including adequate protein throughout your diet and pairing it with resistance exercise.
5. Maintain Healthy Relationships
People aren't meant to live completely isolated lives.
Friends, family, community, hobbies, and meaningful relationships can all contribute to well-being.
Your health isn't just about what's on your plate or how many steps your watch says you took today.
6. Get Preventive Healthcare
Know your numbers.
Get recommended screenings.
Manage conditions you already have.
Take medications as prescribed when appropriate.
Talk with your healthcare provider about changes in your health.
Preventive care isn't particularly exciting, but finding and managing health problems earlier can make a difference.
7. Get Enough Sleep
Sleep isn't optional maintenance.
Your body and brain need it.
Aim for adequate sleep, and pay attention if you consistently struggle to sleep, wake frequently, or feel exhausted despite getting enough hours.
8. Protect Your Brain and Your Body
Wear a seatbelt.
Use appropriate protective equipment.
Prevent falls.
Wear sunscreen.
Don't text while driving.
These aren't longevity hacks.
They're basic common-sense ways to avoid preventable injury and illness.
9. Manage Stress, But Don't Expect a Stress-Free Life
Stress is part of being human.
The goal isn't to eliminate every stressful experience.
Instead, develop ways to recover.
Take breaks.
Spend time outside.
Connect with people.
Exercise.
Do things you enjoy.
Ask for help when you need it.
10. Enjoy Your Life
This one matters too.
If your approach to longevity makes you miserable, I would argue that something has gone wrong.
The goal isn't simply to accumulate as many birthdays as possible.
It's to have a life worth living.
Eat the birthday cake.
Take the vacation.
Go to the concert.
Spend time with the people you love.
And also take care of yourself.
Those things aren't mutually exclusive.
The Car Analogy – I use this a lot, so you may have heard this one before
I often think about our body like a car.
Even if you take really good care of your car, eventually things start to wear out.
You can change the oil.
Replace the tires.
Fix the brakes.
Replace a battery.
Repair whatever breaks.
And if the car eventually becomes too worn out to repair, you can get a new one.
Unfortunately, we don't have that option with our bodies.
Not yet, anyway.
We can repair things.
We can replace some joints.
We can treat diseases.
We can use medications.
We can make cosmetic changes.
We can improve function.
But eventually, something will wear out.
That's part of being human.
So perhaps the better question isn't:
"How can I live forever?"
It's:
"How can I make the years I have as healthy and functional as possible?"
The Bottom Line
Lifespan, life expectancy, and healthy life expectancy describe different things.
Lifespan tells us about how long an individual can live, particularly when we're talking about the potential limits of human longevity.
Life expectancy tells us how long people in a particular population can be expected to live based on mortality patterns.
Healthy life expectancy addresses the more important question: how many of those years are likely to be lived in good health.
That’s the part I think needs the most consideration.
Because I don't just want more years.
I want more good years.
I want to be able to move.
Travel.
Eat foods I enjoy.
Spend time with people I love.
Do the things that make life interesting.
And I suspect most people want something similar.
We can't control every factor that influences how long we'll live.
But we can make choices that support our health without turning our lives into one giant longevity project.
Take care of yourself.
Don't smoke.
Move your body.
Eat a varied diet.
Get enough protein.
Sleep.
Maintain relationships.
Use preventive healthcare.
Avoid unnecessary risks.
And enjoy your life.
Because the goal isn't simply to live longer.
It's to live well for as long as we can.
Sources and further reading:
World Health Organization Health data overview for the United States of America
World Health Organization – The Global Health Observatory Healthy life expectancy (HALE)
CDC National Center for Health Statistics National Vital Statistics System Life Expectancy
Additional Articles:
Healthy Life Expectancy: Adding Life to Your Years (coming next)
Antioxidants and Phytochemicals: What They Are and Why They Matter
Superfoods, Functional Foods, and Nutraceuticals: Do They Really Matter
Embracing Self-Care: What It Really Means and Why It Matters
