What is aging?

Aging is a time-related, progressive decline in physiological function that increases vulnerability to disease and death. While aging is universal, the rate and quality of aging vary widely across individuals, influenced by genes, environment, behaviors, and chance.

The biology of aging

Modern biogerontology describes interconnected processes, often called the “hallmarks of aging,” that drive age-related decline. These include:

• Genomic instability: Accumulated DNA damage from internal and external stressors.
• Telomere attrition: Shortening chromosome end-caps that can limit cell division.
• Epigenetic alterations: Changes in gene regulation (e.g., DNA methylation) that shift cellular programs.
• Loss of proteostasis: Impaired protein folding and clearance, leading to aggregates.
• Deregulated nutrient sensing: Pathways like insulin/IGF-1, mTOR, AMPK, and sirtuins become imbalanced.
• Mitochondrial dysfunction: Reduced energy production and increased reactive oxygen species.
• Cellular senescence: Cells that stop dividing but secrete inflammatory factors.
• Stem cell exhaustion: Diminished regeneration capacity of tissues.
• Altered intercellular communication: Chronic inflammation and immune dysregulation.
• Microbiome dysbiosis: Age-related shifts in gut microbes that affect metabolism and immunity.

These processes are not isolated; interventions that affect one often influence others (for example, exercise can remodel mitochondria, modulate nutrient sensing, and reduce chronic inflammation).

Longevity vs. healthspan

Longevity is the total years lived; healthspan is the years lived in good health, free from significant disability. The goal for individuals and public health is to extend healthspan and compress morbidity—delaying disease onset and reducing time spent with illness.

Genetics and environment

Genetics plays a role in lifespan, but for most people it is modest. Twin and pedigree studies suggest that typical lifespan heritability is about 10–25%. Exceptional longevity (e.g., centenarians) appears more heritable, but still strongly shaped by environment and behavior.

Environmental and social determinants—including education, income, access to healthcare, neighborhood safety, food environment, pollution, and social connection—exert large effects on healthy aging trajectories.

Lifestyle levers with the strongest evidence

While no lifestyle can “stop” aging, certain behaviors reliably reduce risk for the major chronic diseases of aging and improve function.

1) Physical activity and fitness

• Target at least 150–300 minutes/week of moderate aerobic activity or 75–150 minutes/week vigorous, plus muscle-strengthening 2+ days/week.
• Include balance, mobility, and power work to reduce falls and maintain independence.
• Cardiorespiratory fitness (VO₂ max) is a powerful predictor of mortality; moving up even one fitness category confers substantial risk reduction.
• Keep moving throughout the day: reduce prolonged sitting, add walking and standing bouts.

2) Nutrition patterns

• Emphasize minimally processed, plant-forward eating patterns (e.g., Mediterranean or DASH) rich in vegetables, fruits, legumes, nuts, whole grains, and healthy fats (olive oil, omega-3 sources).
• Aim for adequate protein, especially with aging muscle: approximately 1.0–1.6 g/kg/day (individualize based on health status and goals), distributed across meals.
• Limit ultra-processed foods, excess added sugars, and trans fats; moderate alcohol if used at all.
• Maintain energy balance to reduce visceral adiposity. A practical metric: waist-to-height ratio under 0.5.
• Time-restricted eating can help some with calorie control and metabolic markers; long-term benefits and optimal timing vary by individual.

3) Sleep and circadian health

• Prioritize 7–9 hours of quality sleep; keep regular bed/wake times, get morning light, and minimize late-night light and heavy meals.
• Screen and treat sleep disorders such as sleep apnea when indicated.

4) Stress, mental health, and purpose

• Chronic stress accelerates many aging pathways; practices like cognitive behavioral therapy, mindfulness, and regular physical activity can help.
• Purpose in life and positive affect correlate with better health outcomes and longevity.

5) Social connection

• Strong social ties and community participation are linked to lower mortality and better mental health. Invest in relationships and intergenerational connections.

6) Environment and prevention

• Avoid tobacco exposure; minimize air pollution and occupational hazards when possible.
• Practice sun protection; maintain oral health; stay up to date on vaccinations (e.g., influenza, COVID-19, pneumococcal, shingles per guidelines).
• Home safety and balance training reduce fall risk, a major driver of morbidity in older adults.

Medical and emerging interventions

Pharmacological and technological approaches to extend healthspan are an active research area. Most are not yet proven for longevity in humans without specific medical indications.

Cardiometabolic therapies with established benefits

• Blood pressure, lipids, and glucose control deliver large mortality benefits. Discuss statins, antihypertensives, and diabetes therapies when indicated.
• Modern agents like SGLT2 inhibitors and GLP‑1 receptor agonists reduce cardiovascular and kidney risk in appropriate patients.

Candidate “geroprotectors” (research-stage)

• Metformin: Observational links to lower mortality in people with diabetes; the TAME trial aims to test effects on aging-related outcomes in non-diabetics. Not yet approved for longevity.
• Rapamycin/rapalogs: Extend lifespan in multiple species; human data for aging are preliminary and dosing regimens for safety/efficacy in healthy people are not established.
• Senolytics (e.g., dasatinib + quercetin; fisetin): Remove senescent cells in animals and show early signals in small human studies for select conditions; risks and benefits in healthy aging remain uncertain.
• NAD+ boosters (NR, NMN): Mixed human data on functional outcomes; long-term efficacy and safety for aging are unproven. Regulatory status varies by country.
• Resveratrol, spermidine, and other nutraceuticals: Mechanistic rationale with limited or inconsistent human outcome data. Use caution and avoid megadoses.
• Thermal and hormetic stressors: Regular sauna use is observationally linked with lower cardiovascular and all-cause mortality; cold exposure may improve metabolic health markers. Individualize and practice safely.

Important: Talk with a clinician before starting medications or supplements, especially if you have chronic conditions, take other drugs, or are pregnant or breastfeeding.

Biomarkers and testing

No single test “measures” biological age perfectly. A practical, clinically grounded panel emphasizes risk detection and functional capacity:

Core clinical metrics

• Cardiometabolic: blood pressure, lipid panel (consider apoB and Lp(a)), fasting glucose, HbA1c (or OGTT in select cases), fasting insulin, kidney and liver function, hs-CRP.
• Nutritional and endocrine (as indicated): vitamin D, B12, iron studies, thyroid function.
• Body composition: weight, waist circumference, waist-to-height ratio; consider DXA for fat and lean mass.
• Physical function: grip strength, gait speed, chair stand test, balance (e.g., single-leg stand), and VO₂ max or submaximal fitness test.

Advanced and research tools

• Epigenetic clocks (e.g., PhenoAge, GrimAge) estimate biological age; they are promising but not yet definitive for guiding individual treatment.
• Continuous glucose monitoring can help select individuals tailor diet/activity; routine use in healthy people is debated.
• Microbiome, proteomic, and glycomic tests are emerging; clinical applications remain limited.

Safety, hype, and common myths

• There is no proven way to stop or reverse human aging; be wary of unregulated “anti-aging” clinics and stem cell or gene therapy claims without rigorous evidence.
• “Young blood” transfusions and many exotic interventions lack demonstrated safety and efficacy for longevity.
• Longevity is not only about lifespan; preserving function, independence, and quality of life is paramount.

Ethical and societal dimensions

Extending healthy life raises questions about equitable access, intergenerational fairness, environmental sustainability, and how societies organize work, retirement, and caregiving. Policies that improve social determinants of health—education, safety, nutrition, clean air and water, and accessible preventive care—likely yield some of the largest longevity benefits at population scale.

A practical starter plan

Use this 12-week framework to begin compounding benefits. Adjust to your abilities and medical needs.

1. Movement: Accumulate 30–45 minutes/day of moderate activity (e.g., brisk walking or cycling) on 5 days/week. Add two full-body strength sessions focusing on major muscle groups. Include brief mobility work daily.
2. Nutrition: Build meals around plants and protein. Each meal: a palm-sized protein portion, two fists of vegetables, a thumb of healthy fats, and whole-food carbs to appetite and goals. Limit ultra-processed foods.
3. Weight and waist: Track waist-to-height ratio monthly. If above 0.5, prioritize reducing sugary drinks, late-night eating, and alcohol; add daily walks after meals.
4. Sleep: Fix a consistent sleep window; get morning outdoor light; limit screens an hour before bed. If snoring or excessive sleepiness, discuss screening for sleep apnea.
5. Stress and social: Schedule two social engagements weekly; practice 10 minutes/day of a relaxation technique you like.
6. Prevention: Review vaccines and screenings with your clinician; address blood pressure, lipids, and glucose as needed.
7. Measure: Record steps or active minutes, strength progress (reps/loads), resting heart rate, and a simple functional test (e.g., 1-minute sit-to-stand). Reassess at week 12.

Small, sustained improvements across multiple domains usually outperform extreme changes in just one.

References

• López-Otín C, et al. The Hallmarks of Aging. Cell. 2013; and 2023 update: The hallmarks of aging: an expanding universe. Trends Cell Biol. 2023.
• World Health Organization. Guidelines on physical activity and sedentary behaviour. 2020.
• Mandsager K, et al. Association of cardiorespiratory fitness with long-term mortality. JAMA Netw Open. 2018.
• American Academy of Sleep Medicine and Sleep Research Society. Recommended amount of sleep for a healthy adult. 2015.
• Laukkanen T, et al. Sauna bathing and reduced cardiovascular mortality. JAMA Intern Med. 2015.
• AFAR. Targeting Aging with Metformin (TAME) Trial: overview and updates.
• Justice JN, et al. Senolytics in idiopathic pulmonary fibrosis: results of a first-in-human study. EBioMedicine. 2019.
• Ruby JG, et al. Estimates of the heritability of human longevity are substantially inflated due to assortative mating. Genetics. 2018.
• Ashwell M, et al. Waist-to-height ratio as a screening tool. Obes Rev. 2012.
• Estruch R, et al. Primary prevention of cardiovascular disease with a Mediterranean diet. N Engl J Med. 2018.

Note: This article is for informational purposes and does not substitute for professional medical advice.