¶ What is Aging?

Aging is a degenerative process that occurs in all living organisms. It is characterized by a decrease in the ability of the body to function properly.

But to more properly discuss aging, we need to first define the concepts of life expectancy, lifespan, and healthspan.

¶ Life expectancy

We can reasonably expect a new car to last us 12-15 years with proper maintenance, so that is its life expectancy.

What is the life expectancy of a new human?

If we take the data from Portugal in 2024, the life expectancy at birth for females was 85.1 years and for males was 79.4 years.^[1]

Life expectancy is the average number of years a person is expected to live. This is computed by taking the average of the number of years lived by a population.

We have good news! The life expectancy of a new human has been increasing steadily for the past 100 years. Portugal is a bit of an outlier, but the trend is clear worldwide.^[2]

This is due to a combination of factors, including improved healthcare, better nutrition, and increased access to education.^[2:1]

But the main reason is simply that we have cured childhood diseases.^[3]

[Proportion of people living to a given age](https://www.health.org.uk/evidence-hub/health-inequalities/life-expectancy-for-successive-generations)

¶ Lifespan vs Healthspan

Lifespan is the total number of years a person is expected to live.

Healthspan is the number of years a person is expected to live in good health (often operationalized as the World Health Organization's health-adjusted life expectancy, HALE).^[4]

The good news is that "health-adjusted lifespan", i.e. healthspan, has been increasing steadily for the past 100 years.^[4:1]

The bad news is that lifespan has not been faster, which means the gap between lifespan and healthspan has been growing.^[5]

Global Healthspan-Lifespan Gaps Among 183 World Health Organization Member States [(Germany and Terzic, 2024)](https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2827753)

And this is because the diseases caused by aging increase as we age.

Disease Incidence by Age [(ERS, 2024)](https://publications.ersnet.org/content/erj/44/5/1332)

We can say that for many of the diseases our society most worries about, like cancer, heart disease, and Alzheimer's disease, the main risk factor is age itself.

This is now a global problem, and it is getting worse.

Worlds aging population vs young population (Visual Capitalist)

See also: Biomarkers of Aging and Longevity Interventions

¶ Causes of Aging

Aging is a complex, multifactorial process. A widely used framework is the "hallmarks of aging," originally proposed in 2013 and expanded in 2023.^[6][7] Core hallmarks include:

• Genomic instability (DNA damage)
• Telomere attrition
• Epigenetic alterations
• Loss of proteostasis
• Deregulated nutrient sensing
• Mitochondrial dysfunction
• Cellular senescence (interventions)
• Stem cell exhaustion
• Altered intercellular communication (includes chronic inflammation/"inflammaging")
• Disabled macroautophagy (impaired autophagy)
• Dysbiosis (microbiome alterations)

So what can we do about it?

¶ Longevity Interventions

Longevity interventions are interventions that aim to extend lifespan and healthspan. See the overview page: Longevity Interventions.

There are many different types of longevity interventions, including:

• Lifestyle interventions like exercise
• Biohacking interventions
• Pharmaceutical interventions like rapamycin, metformin, and quercetin
• Frontier biomedical interventions like cellular reprogramming, blood-based interventions, stem cell therapy, and therapeutic plasma exchange
• Esthetic interventions

¶ See also

• Biomarkers of Aging
• Chronic Inflammation
• Hallmarks of Aging
• Cellular Reprogramming
• Blood-Based Interventions for Longevity
• Therapeutic Plasma Exchange
• Peptide Therapies
• Regulatory Landscape
• Exercise
• Rapamycin
• Evidence-Based Analysis of Frontier Longevity Interventions

¶ References