The Healthspan Gap

For most of human history, longevity meant one thing: staying alive.

That definition is starting to feel incomplete.

Living to 85 sounds very different depending on whether your seventies and early eighties are spent traveling, working, exercising, thinking clearly and living independently, or managing a growing list of limitations.

That difference is healthspan.

Healthspan is the portion of life spent in good health, with the physical and cognitive capacity to keep participating fully in it. Lifespan tells us how long we live. Healthspan asks a more interesting question:

How many of those years still feel like yours?

Medicine has become remarkably good at keeping people alive.

We treat infections that once killed us. We manage cardiovascular disease, diabetes and cancer more effectively. We replace joints, control blood pressure and intervene earlier when something goes wrong.

But longer survival has created a new challenge.

In a 2024 analysis of 183 countries using World Health Organization data through 2019, researchers found that increases in lifespan had outpaced increases in healthy life expectancy. Globally, the healthspan-lifespan gap had grown to roughly a decade. In the United States, it reached 12.4 years, the largest gap in the analysis.

WHO data tell a similar broader story. Before the pandemic, global life expectancy increased by 6.4 years between 2000 and 2019, while healthy life expectancy increased by 5.3. We gained years, but not all of them were healthy ones.

This is the healthspan gap.

And it changes the longevity conversation completely.

It is easy to think of age-related disease as something that happens later.

Biology is less tidy.

Muscle mass and strength begin changing decades before old age. Cardiometabolic risk can build quietly for years. Blood pressure, glucose regulation, lipids, body composition, sleep and fitness can all shift long before they produce a diagnosis.

For example, the National Institute on Aging notes that muscle mass and strength typically peak around ages 30 to 35, then gradually decline, with losses accelerating later in life. Maintaining strength through resistance exercise can substantially slow that decline and help preserve mobility and independence.

The same long view applies elsewhere.

Cardiorespiratory fitness in early adulthood and its maintenance through midlife have been associated with lower rates of premature death and cardiovascular events later on.

In other words, healthspan is not simply an old-age project.

Much of the gap at the end of life is being influenced in the decades before it.

One useful way to think about healthy aging is reserve.

How much capacity does your body have beyond what everyday life currently demands?

Can you climb several flights of stairs without thinking about it? Carry something heavy? Recover after an intense week? Maintain muscle during illness or weight loss? Handle a disrupted night of sleep without feeling depleted for days?

None of these is a clinical test of longevity. But together they illustrate something important.

A body with more metabolic, cardiovascular and physical reserve generally has more room to absorb the challenges that come with age.

That is why muscle matters beyond aesthetics. Why cardiovascular fitness matters even if you are thin. Why sleep belongs in a conversation about heart and metabolic health. And why a normal result on one annual blood test does not necessarily tell the whole story.

The National Institutes of Health now has an entire field devoted to this idea. Geroscience studies the biology of aging as a contributor to multiple chronic diseases, with the goal of extending the portion of life spent in good health rather than focusing on one disease at a time.

Traditional healthcare tends to divide the body into categories.

Blood sugar goes here. Hormones go there. Sleep is discussed somewhere else. Weight becomes its own conversation. Cardiovascular risk gets another specialist.

Your biology does not experience them separately.

Sleep can influence metabolic and cardiovascular health. Hormonal transitions can affect body composition, bone health and symptoms that influence exercise and recovery. Muscle plays a role in physical function and metabolic health. Blood pressure, lipids and glucose collectively shape cardiovascular risk.

This is one reason looking at trends and relationships can be more useful than chasing an isolated “optimal” number.

The American Heart Association, for example, now evaluates cardiovascular health across eight interconnected areas: diet, physical activity, nicotine exposure, sleep, weight, blood lipids, blood glucose and blood pressure.

No single biomarker can summarize how well you are aging.

The picture matters.

Longevity has become an industry, which can make healthy aging sound far more complicated than it needs to be.

There is exciting research underway in aging biology. New treatments, diagnostics and technologies may eventually change how we approach healthy longevity.

But the strongest evidence today still points toward fundamentals.

Maintain muscle. Preserve cardiovascular fitness. Move consistently. Sleep adequately. Do not smoke. Pay attention to blood pressure, glucose and lipids. Eat in a way that supports metabolic health and adequate nutrition. Keep up with appropriate preventive care.

These factors are not fashionable, but they influence many of the conditions that ultimately shorten healthspan.

And when something is changing, investigate it.

Persistent fatigue, declining recovery, unexpected body-composition changes, disrupted sleep or symptoms during hormonal transitions do not automatically mean something is wrong. They also should not automatically be dismissed as “just getting older.”

They are information.

Understanding the context is what makes that information useful.

This is where the next generation of healthcare has an opportunity to be different.

Not by promising to stop aging.

Not by turning every biomarker into a problem that needs to be treated.

And not by selling a longer list of supplements, medications or tests.

The opportunity is to create a more connected view of health over time.

Your symptoms. Your goals. Your history. Your labs. Your metabolic health. Your hormones. Your treatments. Your lifestyle. Your changing biology.

When those pieces are viewed together, it becomes easier to see patterns, identify meaningful risks and decide what actually deserves attention.

Sometimes the answer is lifestyle.

Sometimes it is monitoring.

Sometimes further testing makes sense.

And sometimes treatment may be appropriate after clinical review.

The point is not intervention for intervention’s sake. It is better information before intervention.

The longevity conversation has spent a lot of time asking how we can add years to life.

Healthspan asks us to look at the other side of the equation.

Can you maintain your strength?

Your clarity?

Your independence?

Your ability to work, travel, move, connect and keep doing the things that make those additional years valuable?

There is no single test that can predict that future. And there is no protocol that guarantees it.

But the trajectory is not completely outside our control either.

The earlier we start paying attention to the signals, building reserve and understanding how our biology is changing, the more opportunity we have to influence the years ahead.

Living longer was the first longevity breakthrough. Living better for longer is the next one.