Lifespan has become a popular way to talk about living well. On its own, it is the wrong target. The goal of longevity medicine reaches past helping people live longer. It is to help them live better for longer.
A 90-year lifespan is not a good outcome if the final 20 years are marked by cognitive decline, physical dependence, chronic pain, and loss of function. Yet that trajectory describes the experience of a large proportion of people who reach old age today.
The measure that matters here is healthspan: the period of life spent in good health, free from serious disease and disability, with the physical and cognitive capacity to do the things that make life meaningful. Extending healthspan, rather than lifespan alone, is the core objective of everything we do at Aeternitas.
Lifespan vs. Healthspan: The Gap That Matters
Average life expectancy in the United States is approximately 78 to 79 years. But Americans spend roughly the last 12 to 13 years of life in less-than-full health, often living with a serious chronic condition that limits function. That is a substantial gap between lifespan and healthspan.
The goal of longevity medicine is not to extend that tail of disability. It is to compress it: to maintain high function well into the 70s, 80s, and beyond, so that decline, when it comes, is steep and late rather than gradual and early.
The physician James Fries first described this idea, which he called the “compression of morbidity,” in 1980: if the onset of chronic disease can be delayed while the age of natural death stays relatively fixed, the period of illness at the end of life shrinks. The evidence that this is achievable is encouraging but not settled. Some population data show low-risk individuals reaching old age with far less cumulative disability, while other analyses find the gap holding steady or widening. What is clear is that the factors driving it are specific, measurable, and modifiable.
What Drives Healthspan
A handful of domains have the strongest research support for healthspan, and they are where the most meaningful gains are made. At Aeternitas, a member’s care works across all of them, weighted by what the baseline assessment shows. Not every area needs the same level of attention for every patient.
Cardiovascular Fitness
Cardiorespiratory fitness, measured as VO2 max, is among the strongest predictors of both lifespan and healthspan available in medicine. In a 2024 overview of meta-analyses covering more than 20 million people, higher fitness was associated with roughly half the all-cause mortality risk of low fitness, and each step up in fitness category tracked with substantially lower cardiovascular, metabolic, and cancer mortality. High fitness in your 40s and 50s is also one of the strongest predictors of physical function and independence in your 80s.
Building and maintaining your aerobic base, through consistent Zone 2 training and structured higher-intensity work, is foundational to healthspan rather than optional.
Strength and Musculoskeletal Reserve
Skeletal muscle mass peaks in the 30s and declines progressively thereafter, a process called sarcopenia. Losses are modest in midlife but accelerate later; by the eighth or ninth decade, a sedentary person may have lost up to half of their peak muscle mass. The consequences are significant: falls and fractures (a leading cause of injury death in older adults), loss of metabolic resilience, reduced insulin sensitivity, and diminished physical capacity.
Resistance training that is structured, progressive, and supervised is the primary intervention for preserving muscle mass and function. Grip strength alone is among the most replicated predictors of mortality in the research literature. At Aeternitas, strength is measured, targeted, and trained, not assumed.
Metabolic Health
Insulin resistance, visceral adiposity, and metabolic syndrome are upstream drivers of cardiovascular disease, type 2 diabetes, non-alcoholic fatty liver disease, and several cancers. They are also associated with cognitive decline and biological aging.
Metabolic health is a spectrum, not a binary. Most people who eventually develop type 2 diabetes have a decade or more of measurable, treatable metabolic dysfunction before their blood glucose becomes diagnostic. Our biomarker panel is designed to capture that dysfunction early, and our nutrition, exercise, sleep, and pharmacological interventions address it specifically.
Cognitive Reserve and Brain Health
Alzheimer’s disease and other dementias represent one of the greatest healthspan threats of our era. In sporadic (non-familial) Alzheimer’s, the amyloid and tau pathology that underlies the disease begins changing 15 to 20 years before symptoms appear, with amyloid the earliest signal and tau changes following later. By the time memory symptoms are noticeable, the window for meaningful prevention has largely narrowed.
Building cognitive reserve, the brain’s resilience to pathological change, through sustained physical fitness, social engagement, cognitive challenge, sleep quality, and vascular health is among the most evidence-supported strategies for reducing dementia risk. At Aeternitas, neurocognitive baseline testing is part of evaluation day, and brain health is a specific domain of the care plan for patients with elevated risk.
Sleep
Sleep is when growth hormone is secreted to support cellular repair and muscle recovery, the immune system consolidates its defenses, and, by emerging evidence, the brain clears metabolic waste through what is called the glymphatic system, a process still being mapped in humans. Chronic sleep restriction, even mild restriction to about six hours, is associated with elevated inflammatory markers, impaired metabolic function, and higher rates of cardiovascular disease, cancer, and dementia.
Sleep is not a lifestyle preference. At the physiological level, it is maintenance. We screen for sleep disorders, manage common ones such as obstructive sleep apnea with standard treatment as part of primary care, and coordinate with a sleep specialist when a case calls for it.
The Role of Pharmacotherapy in Healthspan
Beyond the lifestyle domains, there is a growing and legitimate role for targeted pharmacological interventions in healthspan. At Aeternitas, pharmacotherapy decisions are made based on your individual data, risk profile, and evidence quality, not on trend.
Medications with meaningful evidence include statins and PCSK9 inhibitors for cardiovascular risk reduction, both supported by large outcome trials; GLP-1 receptor agonists for metabolic health, with evidence now extending to cardiovascular risk; hormone replacement therapy with appropriate patient selection; and metformin for metabolic health. Metformin is sometimes discussed as a longevity agent, but a healthspan benefit in people without diabetes has not been established, and we use it for metabolic indications rather than as an anti-aging measure.
Measuring Healthspan Progress
Unlike lifespan, healthspan is measurable now. The metrics we track at Aeternitas that best reflect healthspan trajectory include:
- VO2 max, among the strongest single predictors of functional longevity
- Grip strength and lean mass, direct markers of musculoskeletal reserve and sarcopenia risk
- Cardiovascular risk markers, including ApoB, Lp(a), CAC score, blood pressure, and inflammatory markers
- Metabolic markers, including fasting insulin, HOMA-IR, HbA1c trend, and visceral fat by DEXA
- Neurocognitive scores, baseline and trend over annual re-testing
- Sleep quality, objective sleep staging and disorder screening
Each of these is re-measured at regular intervals. The trajectory matters as much as the baseline. Is your VO2 max improving or declining? Are your metabolic markers moving in the right direction? These trends are the report card for your healthspan program.
Frequently Asked Questions
What is the difference between healthspan and lifespan?
Lifespan is the total duration of life. Healthspan is the portion of that life spent in good health, free from serious chronic disease and disability, with maintained physical and cognitive function. The goal of longevity medicine is to extend healthspan so that it approaches lifespan: living well until close to the end, rather than spending the last decade or more in decline.
What is the most important thing you can do to extend healthspan?
If asked to name one, it would be building and maintaining your cardiovascular fitness. The evidence for VO2 max as a predictor of functional longevity and disease-free life is among the strongest for any single modifiable factor. Extending healthspan is multi-factorial, though, and no single intervention substitutes for a comprehensive, individualized approach.
Can you improve healthspan after 50?
Yes. The research is clear that cardiovascular fitness, muscle mass, and metabolic health all respond to intervention at any age. The benefits are often proportionally larger for people starting from a lower baseline. It is never too late, though earlier action compounds more favorably.
How does Aeternitas measure and track healthspan?
Aeternitas tracks healthspan through a set of functional, biomarker, imaging, and cognitive measures, re-tested annually as part of your ongoing membership. The aim is not a single snapshot but a trajectory: a clear, data-driven picture of how your healthspan is evolving over time.
About the Author
Dr. Corey Helton, MD is the founder of Aeternitas Health, a physician-led longevity and precision medicine practice in Charlotte, NC. He founded Aeternitas to practice anticipatory, data-driven medicine aimed at long-term outcomes rather than present symptoms alone. Aeternitas is a direct-pay practice with a deliberately limited panel.
References
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Medically reviewed by Dr. Corey Helton, MD. Review date: June 2026
This article is for general educational purposes only. It is not medical advice and is not a substitute for diagnosis or treatment by a qualified physician. Reading it does not create a physician-patient relationship with Aeternitas. Talk with your own physician before making changes to your health, medications, supplements, or care.
