TL;DR — Longevity research has shifted from chasing lifespan (total years lived) to healthspan (years lived in good health). The 2023 update to the Hallmarks of Aging framework identifies twelve interconnected biological processes that drive age-related decline. Across the peer-reviewed literature, four lifestyle variables show the most consistent association with longer healthspan: cardiorespiratory fitness, sleep quality, adequate protein intake, and metabolic health.
Healthspan is the period of life spent free from chronic disease and significant functional decline. Lifespan is total years lived. A person can have a long lifespan but a short healthspan — for example, living into their 90s but spending the last 15 years managing frailty, cognitive decline, or cardiovascular disease.
Research groups, including those behind the influential Hallmarks of Aging papers, increasingly frame the goal of longevity science as compressing morbidity: extending the healthy years and shortening the period of end-of-life decline [1][2].
In 2013, López-Otín and colleagues proposed nine hallmarks of aging — cellular and molecular processes that, when dysregulated, contribute to biological aging [1]. The 2023 update expanded the framework to twelve hallmarks, grouped into three categories [2]:
Primary hallmarks (causes of damage) - Genomic instability - Telomere attrition - Epigenetic alterations - Loss of proteostasis - Disabled macroautophagy
Antagonistic hallmarks (responses to damage) - Deregulated nutrient-sensing - Mitochondrial dysfunction - Cellular senescence
Integrative hallmarks (culprits of phenotype) - Stem cell exhaustion - Altered intercellular communication - Chronic inflammation - Dysbiosis (microbiome dysregulation)
Each hallmark is a research target. Understanding them helps explain why certain lifestyle interventions — discussed below — appear to influence how people age.
The clinical and epidemiological literature is large and sometimes contradictory, but four variables stand out for the consistency of their association with longer healthspan.
A 2018 JAMA Network Open study of more than 122,000 patients found that higher cardiorespiratory fitness was associated with significantly lower long-term mortality, with no observed upper limit of benefit [3]. The effect size was comparable to, or larger than, traditional risk factors like smoking and diabetes.
→ Read more: VO2 Max as a Longevity Biomarker → Read more: Zone 2 Cardio and Mitochondrial Health
A meta-analysis published in Sleep pooled data from 16 prospective studies covering over 1.3 million participants and found a U-shaped relationship between sleep duration and all-cause mortality, with both short (<7 hours) and long (>9 hours) sleep associated with elevated risk [4]. Sleep also plays a central role in glymphatic clearance and metabolic regulation.
→ Read more: Sleep Architecture and Biological Aging
The PROT-AGE Study Group — an international consensus of geriatricians and nutrition researchers — recommends that adults over 65 consume 1.0–1.2 g of protein per kg of body weight per day, higher than the standard RDA, to help preserve muscle mass and function with aging [5]. Sarcopenia (age-related muscle loss) is a strong independent predictor of falls, disability, and mortality.
→ Read more: Protein Intake and Sarcopenia Prevention After 40
Insulin sensitivity, visceral adiposity, and glycemic control are tightly linked to several hallmarks of aging, including deregulated nutrient-sensing and mitochondrial dysfunction [2]. Metabolic dysfunction is upstream of cardiovascular disease, type 2 diabetes, and many cancers.
It's worth being precise about the limits of current evidence:
Honest longevity medicine is about stacking interventions with strong evidence for healthspan — not chasing headlines.
A practical starting framework, supported by the literature above:
Individual circumstances vary, and working with a clinician to interpret labs and build a personalized plan is the next step.
Is healthspan the same as life expectancy? No. Life expectancy is the average number of years a person is expected to live. Healthspan refers specifically to the years lived without major chronic disease or functional impairment.
What is the single most important factor for longevity? No single factor dominates, but cardiorespiratory fitness has one of the strongest and most consistent associations with all-cause mortality in large observational studies [3].
Can I measure my biological age? Epigenetic clocks (such as DNAm-based tests) estimate biological age from DNA methylation patterns. They are useful research tools, but their ability to guide clinical decisions is still being evaluated.
Do longevity supplements work? As of this writing, no supplement has been shown in rigorous human randomized trials to extend maximum human lifespan. Some compounds are being actively studied; results should be interpreted cautiously.
Charles Kamen, MD earned his medical degree from Albert Einstein College of Medicine and completed his internal medicine internship at Yale-New Haven Hospital, followed by a neurology residency at Loma Linda University. He is board-certified by the American Board of Psychiatry and Neurology and practices longevity and neurological medicine.
This article is for educational purposes and does not constitute medical advice. Consult a qualified clinician before making changes to your health regimen.