# Longevity Lab

> Evidence-based longevity science in plain English. Every claim is sourced
> to peer-reviewed research, with the PubMed reference listed in the article.

Published by Longevity Lab. Educational content, not medical advice.
Licence: free to read; quote with attribution to the article URL.

## Guides

- [Health Through Menopause: A Longevity Guide for Women](https://longevity-lab.fit/health-through-menopause-a-longevity-guide-for-women): Health through menopause: estrogen decline hits bone and heart first, so track your numbers, lift weights, get protein and vitamin D, weigh hormone therapy.
- [How to Protect Joint Health and Prevent Osteoarthritis](https://longevity-lab.fit/how-to-protect-joint-health-and-prevent-osteoarthritis): How to protect joint health: movement feeds cartilage, weight and muscle strength drive osteoarthritis risk, supplements help little, and where to start.
- [How to Support Your Immune System as You Age](https://longevity-lab.fit/how-to-support-your-immune-system-as-you-age): How to support your immune system as you age: protein, vitamin D and zinc, 7–9 hours of sleep, moderate exercise, gut fiber and the right vaccines.
- [How to Improve Metabolic Health: A Practical Guide](https://longevity-lab.fit/how-to-improve-metabolic-health-a-practical-guide): How to improve metabolic health: track five markers, cut refined sugar, walk 10-15 minutes after meals, train for muscle, and sleep enough to lower insulin.
- [Evidence-Based Anti-Aging Skincare: A Practical Guide](https://longevity-lab.fit/evidence-based-anti-aging-skincare-a-practical-guide): Evidence-based anti-aging skincare: daily SPF matters most, then retinoids, vitamin C, niacinamide and a moisturizer. What works and how to build a routine.
- [How to Strengthen Bones and Prevent Osteoporosis](https://longevity-lab.fit/how-to-strengthen-bones-and-prevent-osteoporosis): To strengthen bones and prevent osteoporosis: calcium, vitamin D, K2 and protein, strength and impact training, fall prevention, and a timely DEXA scan.
- [How to Support Gut Health and Your Microbiome](https://longevity-lab.fit/how-to-support-gut-health-and-your-microbiome): Gut health comes down to plant variety, not pills: aim for 30 different plants a week, add fermented foods, and cut ultra-processed food and sugar.
- [How to Lower Stress and Build Resilience](https://longevity-lab.fit/how-to-lower-stress-and-build-resilience): How to lower stress: breathe with a longer exhale to stop acute spikes, then use sleep, movement, daylight and connection to build lasting resilience.
- [Heart Health: A Prevention Guide for Longevity](https://longevity-lab.fit/heart-health-a-prevention-guide-for-longevity): Heart health for longevity: track blood pressure, LDL and ApoB, glucose and waist, then manage them with diet, cardio, strength training, sleep, no smoking.
- [How to Eat for Brain Health: A Cognitive Longevity Guide](https://longevity-lab.fit/how-to-eat-for-brain-health-a-cognitive-longevity-guide): Eating for brain health means the MIND pattern: leafy greens and vegetables daily, berries, nuts, fish, legumes, olive oil, and less ultra-processed food.
- [How to Build a Longevity Supplement Plan](https://longevity-lab.fit/how-to-build-a-longevity-supplement-plan): Build a longevity supplement plan from lab tests, not trends: close confirmed deficiencies first, add one or two goal-specific items, then check interactions.
- [How to Improve Sleep: A Practical Sleep Hygiene Protocol](https://longevity-lab.fit/how-to-improve-sleep-a-practical-sleep-hygiene-protocol): How to improve sleep: an eight-habit sleep hygiene protocol, how many hours you need, what to do about insomnia (CBT-I), and a two-week reset plan.
- [How to Build a Longevity Diet: A Practical Guide](https://longevity-lab.fit/how-to-build-a-longevity-diet-a-practical-guide): How to build a longevity diet: half the plate vegetables, a quarter protein, a quarter whole carbs, 1.2–1.6 g protein per kg, plus a 4-week plan.
- [How to Build a Training Program for Longevity](https://longevity-lab.fit/how-to-build-a-training-program-for-longevity): A longevity training program combines zone 2 cardio, intervals and strength: 150–300 minutes a week plus two strength sessions. Weekly plans by level.
- [Biohacking for Beginners: A Practical Guide](https://longevity-lab.fit/biohacking-for-beginners-a-practical-guide): Biohacking for beginners: start with sleep, movement and food, not gadgets or supplements. The priority pyramid, what to measure, and a 30-day plan.
- [How to Slow Aging: What Actually Works](https://longevity-lab.fit/how-to-slow-aging-what-actually-works): How to slow aging: exercise, a Mediterranean-style diet, 7-9 hours of sleep, no smoking and key markers in range, with WHO numbers and a 4-week plan.

## News

- [Mediterranean and MIND Diets Cut Dementia Risk](https://longevity-lab.fit/mediterranean-and-mind-diets-cut-dementia-risk): Long-term adherence to the Mediterranean and MIND diets is linked to lower dementia risk in cohorts followed for over 40 years (Alzheimers Dement, 2026).
- [Omega-3 Slowed Biological Aging in the DO-HEALTH Trial](https://longevity-lab.fit/omega-3-slowed-biological-aging-in-the-do-health-trial): DO-HEALTH trial: 1 g of omega-3 a day slowed biological aging on epigenetic clocks in 777 older adults, and stacked with vitamin D and exercise.
- [A 10-Hour Eating Window Aided Weight Loss: TREAD Trial](https://longevity-lab.fit/a-10-hour-eating-window-aided-weight-loss-tread-trial): In the TREAD randomized trial (Obesity, 2026) a 10-hour eating window cut body weight by about 4.6% in 12 weeks, versus 1.7% with usual care.
- [Strength Training and Longevity: 90 to 120 Minutes a Week](https://longevity-lab.fit/strength-training-and-longevity-90-to-120-minutes-a-week): About 90 to 120 minutes of strength training a week is tied to the lowest risk of death: a 30-year study of 147,000 people found a 13% lower risk.
- [A Blood Test Can Now Estimate the Age of Your Organs](https://longevity-lab.fit/a-blood-test-can-now-estimate-the-age-of-your-organs): A blood test can now estimate the biological age of your organs: plasma protein signatures track cellular aging and predict disease risk and mortality.
- [Vitamin D Slowed Telomere Shortening in VITAL Trial](https://longevity-lab.fit/vitamin-d-slowed-telomere-shortening-in-vital-trial): Vitamin D and telomeres: in the VITAL randomized trial, 2,000 IU of D3 daily slowed telomere shortening over 4 years, while marine omega-3 had no effect.
- [Shingles Vaccine Linked to Lower Dementia Risk](https://longevity-lab.fit/shingles-vaccine-linked-to-lower-dementia-risk): A natural experiment in Wales found people who got the shingles vaccine were about 20% less likely to be diagnosed with dementia over roughly 7 years.
- [Aerobic Training Slowed the Epigenetic Clock](https://longevity-lab.fit/aerobic-training-slowed-the-epigenetic-clock): Aerobic training slowed the epigenetic clock: 6 months of cycling raised VO₂max about 20% and slowed GrimAge in a 2026 GeroScience pilot study.
- [FDA Clears First Human Trial of Cellular Rejuvenation](https://longevity-lab.fit/fda-clears-first-human-trial-of-cellular-rejuvenation): The FDA cleared the first human trial of cellular rejuvenation: Life Biosciences' ER-100 uses partial epigenetic reprogramming to treat optic nerve disease.
- [Blue Zones Longevity Data Called Into Question](https://longevity-lab.fit/blue-zones-longevity-data-called-into-question): Blue Zones longevity data is under scrutiny: extreme-age records cluster where birth registration was poor. What still holds up, and what to doubt.
- [Weight-Loss Drugs Cut Cardiovascular Risk](https://longevity-lab.fit/weight-loss-drugs-cut-cardiovascular-risk): Semaglutide cardiovascular risk: in the SELECT trial of over 17,000 people with obesity and no diabetes, heart attack and stroke risk fell by about 20%.
- [Cellular Reprogramming: Scientists Try to Reverse Aging](https://longevity-lab.fit/cellular-reprogramming-scientists-try-to-reverse-aging): Cellular reprogramming aims to reverse aging in cells. It restored vision in old mice and reached a first human trial in 2026, but is unproven in humans.
- [Rapamycin in Healthy Adults: First PEARL Trial Results](https://longevity-lab.fit/rapamycin-in-healthy-adults-first-pearl-trial-results): The PEARL trial tested rapamycin in healthy adults: low intermittent doses over about a year were well tolerated but produced only modest gains.
- [Taurine Deficiency May Accelerate Aging, Study Finds](https://longevity-lab.fit/taurine-deficiency-may-accelerate-aging-study-finds): Taurine deficiency may accelerate aging: in mice, taurine extended lifespan by 10–12%. In humans the link is observational, with no clinical trial yet.

## Body & Mind

- [Cold Exposure and Health: What the Research Shows](https://longevity-lab.fit/cold-exposure-and-health-what-the-research-shows): Cold exposure activates brown fat and may improve insulin sensitivity in small studies, but no human data show it extends lifespan. The evidence and risks.
- [Social Connection and Life Expectancy](https://longevity-lab.fit/social-connection-and-life-expectancy): Strong social connections are associated with roughly one and a half times lower risk of death, comparable to quitting smoking. Why loneliness harms you.
- [Strength Training Against Sarcopenia](https://longevity-lab.fit/strength-training-against-sarcopenia): Strength training is the main proven way to slow and partly reverse sarcopenia: what the research shows, how to train safely, and how much protein you need.
- [Sauna and Heart Health: What the Research Shows](https://longevity-lab.fit/sauna-and-heart-health-what-the-research-shows): Regular sauna use is linked to lower cardiovascular death in Finnish studies, best at 4–7 sessions a week. How heat helps the heart, and who must be careful.
- [How Many Steps a Day You Actually Need](https://longevity-lab.fit/how-many-steps-a-day-you-actually-need): Most benefit arrives at 7,000–8,000 steps a day, not 10,000, and older adults gain from 4,000–5,000. How many steps a day you need, and why pace counts.
- [Stress and Aging: How Chronic Stress Wears You Down](https://longevity-lab.fit/stress-and-aging-how-chronic-stress-wears-you-down): Chronic stress accelerates aging: high cortisol, low-grade inflammation, shorter telomeres, worse sleep. What it does to your body and what lowers it.
- [Grip Strength as a Marker of Longevity](https://longevity-lab.fit/grip-strength-as-a-marker-of-longevity): Grip strength predicts all-cause mortality in large cohorts, sometimes better than blood pressure. What it reflects, how to measure it, how to improve it.
- [VO2 Max: Why Aerobic Fitness Predicts Longevity](https://longevity-lab.fit/vo2-max-why-aerobic-fitness-predicts-longevity): VO2 max is one of the strongest predictors of mortality. What it measures, how to estimate yours, and how zone 2 plus intervals raise it at any age.
- [How Sleep Affects Aging and How Much You Need](https://longevity-lab.fit/how-sleep-affects-aging-and-how-much-you-need): Most adults need 7–9 hours: how sleep and aging are linked, what each sleep stage repairs, what short sleep costs you, and how to sleep better.

## Reviews

- [Curcumin and Longevity: An Evidence Review](https://longevity-lab.fit/curcumin-and-longevity-an-evidence-review): Curcumin eases osteoarthritis pain and inflammation in human trials, but curcumin and longevity evidence is absent, and bioavailability is very low.
- [Glycine and GlyNAC: A Longevity Evidence Review](https://longevity-lab.fit/glycine-and-glynac-a-longevity-evidence-review): GlyNAC (glycine + NAC) rebuilds glutathione, which falls with age. It extended lifespan in mice; human evidence is limited to small marker trials.
- [Coenzyme Q10 and Longevity: An Evidence Review](https://longevity-lab.fit/coenzyme-q10-and-longevity-an-evidence-review): Coenzyme Q10 has real evidence in heart failure and in older adults taking it with selenium, but no proven anti-aging benefit for healthy people.
- [Fisetin and Senolytics: Clearing Senescent Cells](https://longevity-lab.fit/fisetin-and-senolytics-clearing-senescent-cells): Fisetin is a flavonoid studied as a senolytic to clear senescent cells: what is proven in mice, what human trials show, dosing schedules and safety.
- [Berberine, the Natural Metformin: An Evidence Review](https://longevity-lab.fit/berberine-the-natural-metformin-an-evidence-review): Berberine activates AMPK like metformin and lowers glucose and lipids in trials, but human longevity evidence is absent and drug interactions are real.
- [Taurine and Longevity: Reviewing the Evidence](https://longevity-lab.fit/taurine-and-longevity-reviewing-the-evidence): Taurine and longevity: a 2023 Science study extended lifespan in mice by 10-12%, but human evidence is only correlational. Sources, doses and safety.
- [Spermidine and Longevity: The Autophagy Evidence](https://longevity-lab.fit/spermidine-and-longevity-the-autophagy-evidence): Spermidine is a natural polyamine that induces autophagy. It extends lifespan in animals; in humans, higher dietary intake is linked to lower mortality.
- [Rapamycin and Aging: Reviewing the Geroprotector Evidence](https://longevity-lab.fit/rapamycin-and-aging-reviewing-the-geroprotector-evidence): Rapamycin raised median lifespan in mice by 10–25% in the NIA ITP program, but no human trial shows life extension. The geroprotector evidence, doses, risks.
- [Metformin and Longevity: A Review of the Evidence](https://longevity-lab.fit/metformin-and-longevity-a-review-of-the-evidence): Metformin and longevity: no evidence yet that it extends life in healthy people. What observational data, animal studies and the TAME trial show.

## Nutrition

- [Fiber, the Microbiome, and Longevity](https://longevity-lab.fit/fiber-the-microbiome-and-longevity): Fiber feeds the gut bacteria tied to healthy aging and lower mortality. How much fiber you need daily, the best food sources, and why food beats probiotics.
- [Caloric Restriction and Lifespan](https://longevity-lab.fit/caloric-restriction-and-lifespan): Caloric restriction extends lifespan in animals. In humans the CALERIE trial cut intake by 12% for two years and improved metabolic markers and pace of aging.
- [The Mediterranean Diet and Longevity: The Evidence](https://longevity-lab.fit/the-mediterranean-diet-and-longevity-the-evidence): The Mediterranean diet is the most studied eating pattern for longevity: in the PREDIMED trial it cut major cardiovascular events by about 30%.
- [Coffee and Longevity: What the Research Shows](https://longevity-lab.fit/coffee-and-longevity-what-the-research-shows): Moderate coffee (3–4 cups a day) is associated with lower all-cause mortality, type 2 diabetes and liver disease. What the coffee and longevity data show.
- [How Much Protein You Need After 40 to Keep Muscle](https://longevity-lab.fit/how-much-protein-you-need-after-40-to-keep-muscle): After 40 you need about 1.2–1.6 g of protein per kg of body weight a day to keep muscle. How to spread it across meals, best sources, and the kidney myth.
- [Glycation and AGEs: How Sugar Ages Your Tissues](https://longevity-lab.fit/glycation-and-ages-how-sugar-ages-your-tissues): Glycation binds sugar to proteins and forms AGEs that stiffen skin and arteries. What AGEs are, why they build up with age, and how to lower them.
- [What People Eat in the Blue Zones and What Works](https://longevity-lab.fit/what-people-eat-in-the-blue-zones-and-what-works): People in the Blue Zones eat mostly plants: legumes, vegetables, whole grains and nuts, with little meat. Here is what the evidence really supports.
- [Intermittent Fasting and Longevity: The Evidence](https://longevity-lab.fit/intermittent-fasting-and-longevity-the-evidence): Intermittent fasting helps with weight loss and metabolic markers, but no human trial shows it extends lifespan. What 16:8, 5:2 and TRE actually do.

## Supplements

- [Magnesium and Healthy Aging](https://longevity-lab.fit/magnesium-and-healthy-aging): Magnesium and healthy aging: adequate intake is tied to less heart disease, diabetes and mortality. Aim for 300-400 mg a day, mostly from food.
- [Creatine for Muscle, Brain, and Healthy Aging](https://longevity-lab.fit/creatine-for-muscle-brain-and-healthy-aging): Creatine monohydrate at 3-5 g a day plus strength training builds muscle and strength, may support memory in older adults, and is safe for healthy kidneys.
- [Omega-3 and Longevity: Fish, Supplements, Evidence](https://longevity-lab.fit/omega-3-and-longevity-fish-supplements-evidence): Omega-3 and longevity: fatty fish 2–3 times a week is linked to lower cardiovascular risk; supplements pay off mainly with high triglycerides or a low index.
- [Vitamin D and Longevity: Who Needs a Supplement](https://longevity-lab.fit/vitamin-d-and-longevity-who-needs-a-supplement): Vitamin D and longevity: a supplement helps most when you are deficient. What VITAL found, the telomere signal, who needs one and why megadoses fail.
- [Resveratrol and Longevity: What Is Actually Proven](https://longevity-lab.fit/resveratrol-and-longevity-what-is-actually-proven): Resveratrol activates sirtuins and improved health in mice, but no longevity benefit is proven in humans. The bioavailability problem and the red wine myth.
- [NMN: What the Research Actually Shows](https://longevity-lab.fit/nmn-what-the-research-actually-shows): NMN research in humans: NMN reliably raises NAD+ levels, but no trial shows it slows aging. What the evidence supports, and what it does not.

## Biological Age

- [Senescent Cells and Senolytics Explained Simply](https://longevity-lab.fit/senescent-cells-and-senolytics-explained-simply): Senescent cells stop dividing but never die and keep inflammation running. What senolytics are, what is proven in mice and humans, and why not to self-treat.
- [Chronic Inflammation and Aging: Inflammaging](https://longevity-lab.fit/chronic-inflammation-and-aging-inflammaging): Inflammaging is chronic low-grade inflammation that rises with age and is linked to heart disease, diabetes and dementia. Where it comes from, what lowers it.
- [Which Blood Tests Reflect Aging and How to Read Them](https://longevity-lab.fit/which-blood-tests-reflect-aging-and-how-to-read-them): Blood pressure, fasting glucose and HbA1c, lipids and waist size are the core blood tests for aging: what each shows, what a doctor adds, how often to test.
- [Can You Lengthen Telomeres? What Science Says](https://longevity-lab.fit/can-you-lengthen-telomeres-what-science-says): There is no proven way to lengthen telomeres: telomerase activation raises cancer risk and supplements lack evidence. What lifestyle actually changes.
- [Epigenetic Clocks: Measuring Age from DNA](https://longevity-lab.fit/epigenetic-clocks-measuring-age-from-dna): Epigenetic clocks estimate age from DNA methylation. Compare Horvath, Hannum, GrimAge and DunedinPACE, how accurate they are, and what they cannot tell you.
- [What Biological Age Is and How to Measure It](https://longevity-lab.fit/what-biological-age-is-and-how-to-measure-it): Biological age estimates how worn your body really is, not how long you have lived. How it is measured: epigenetic clocks, PhenoAge blood scores, telomeres.

## Glossary

Plain-English definitions. Index: https://longevity-lab.fit/glossary

- [Albumin](https://longevity-lab.fit/glossary/albumin): Albumin is the most abundant protein in blood plasma, made by the liver. What the test measures, usual adult ranges, and why a low albumin matters.
- [Alkaline phosphatase (ALP)](https://longevity-lab.fit/glossary/alkaline-phosphatase-alp): Alkaline phosphatase (ALP) is an enzyme from the bile ducts and bone. What the blood test measures, the typical adult range, and what raises or lowers it.
- [Allostatic load](https://longevity-lab.fit/glossary/allostatic-load): Allostatic load is the cumulative wear on the body from long-term stress, scored from cortisol, inflammation, blood pressure and metabolic markers.
- [Alzheimer’s disease](https://longevity-lab.fit/glossary/alzheimers-disease): Alzheimer’s disease is the most common cause of dementia: beta-amyloid plaques, tau tangles and dying neurons. How it is diagnosed and what lowers risk.
- [Amino acids](https://longevity-lab.fit/glossary/amino-acids): Amino acids are the building blocks of every protein in the body: what the 20 standard and 9 essential ones do, how much you need, and why aging changes it.
- [AMPK](https://longevity-lab.fit/glossary/ampk): AMPK is the enzyme that senses low cellular energy and switches cells from building to burning. What it does, how exercise, fasting and metformin affect it.
- [Amyloid](https://longevity-lab.fit/glossary/amyloid): Amyloid is a misfolded protein that clumps into insoluble deposits; in the brain, beta-amyloid plaques. How amyloid is measured and what changes it.
- [Anemia](https://longevity-lab.fit/glossary/anemia): Anemia is a shortage of hemoglobin or red blood cells, so blood carries less oxygen. What the blood count shows, the usual cut-offs and what causes it.
- [Anxiety](https://longevity-lab.fit/glossary/anxiety): Anxiety is anticipatory fear about a threat that has not arrived: how normal anxiety differs from an anxiety disorder, how it is scored, and what helps.
- [Apoptosis](https://longevity-lab.fit/glossary/apoptosis): Apoptosis is programmed cell death: what it is, how it differs from necrosis, why the body needs it, and how it links to cancer, senescence and aging.
- [ASCVD](https://longevity-lab.fit/glossary/ascvd): ASCVD 10-year risk is the estimated chance of a first heart attack or stroke within ten years: what goes into the score, the bands, and what moves it.
- [Atherosclerosis](https://longevity-lab.fit/glossary/atherosclerosis): Atherosclerosis is the slow buildup of cholesterol-rich plaque in artery walls. What it is, how it is measured, and what actually slows it down.
- [Atrial fibrillation](https://longevity-lab.fit/glossary/atrial-fibrillation): Atrial fibrillation is a fast, disorganized heart rhythm: how it is found on an ECG, why it raises stroke and heart failure risk, and what changes it.
- [Autophagy](https://longevity-lab.fit/glossary/autophagy): Autophagy is how a cell breaks down and recycles its own damaged parts. What it is, how fasting, exercise and mTOR affect it, and what is proven in humans.
- [Biological age](https://longevity-lab.fit/glossary/biological-age): Biological age is an estimate of your body's condition from biomarkers, not your birth date: what it measures, typical outputs and what changes it.
- [Biomarker of aging](https://longevity-lab.fit/glossary/biomarker-of-aging): A biomarker of aging is a measurable indicator of how fast your body is aging: what qualifies as one, which tests are used and what actually moves them.
- [Blood glucose](https://longevity-lab.fit/glossary/blood-glucose): Blood glucose is the amount of sugar circulating in your blood. What a fasting test measures, the normal, prediabetes and diabetes bands, and what moves it.
- [Blood pressure (BP)](https://longevity-lab.fit/glossary/blood-pressure-bp): Blood pressure (BP) is the force of blood against artery walls, given as systolic over diastolic in mmHg. What the numbers mean and what moves them.
- [Blue zones](https://longevity-lab.fit/glossary/blue-zones): Blue zones are regions where an unusual share of people reach 90 or 100: which five they are, the habits residents share, and why the records are disputed.
- [BMI](https://longevity-lab.fit/glossary/bmi): BMI (body mass index) is body weight in kilograms divided by height in meters squared: the WHO categories, what BMI misses, and what actually changes it.
- [Body composition](https://longevity-lab.fit/glossary/body-composition): Body composition is the split of your body weight into fat mass and lean mass. What it measures, how it is assessed, typical ranges and what changes it.
- [Bone densitometry](https://longevity-lab.fit/glossary/bone-densitometry): Bone densitometry is a low-dose X-ray scan of bone mineral density. What it measures, what a T-score means, and what actually moves your result.
- [C-reactive protein (CRP)](https://longevity-lab.fit/glossary/c-reactive-protein-crp): C-reactive protein (CRP) is a liver-made marker of inflammation. What the blood test measures, how the hs-CRP risk bands read, and what actually lowers it.
- [Calcium](https://longevity-lab.fit/glossary/calcium): Calcium is the mineral stored in bone and used in trace amounts by nerves and muscle. What a blood calcium test measures, typical ranges and what moves it.
- [Cardiorespiratory fitness](https://longevity-lab.fit/glossary/cardiorespiratory-fitness): Cardiorespiratory fitness is the body's ability to deliver and use oxygen during exercise. What VO2 max measures, how it is read, and what raises it.
- [Cardiovascular disease (CVD)](https://longevity-lab.fit/glossary/cardiovascular-disease-cvd): Cardiovascular disease (CVD) is the umbrella term for heart and blood vessel disorders: what it covers, how risk is estimated, and what actually lowers it.
- [Celiac disease](https://longevity-lab.fit/glossary/celiac-disease): Celiac disease is an autoimmune reaction to gluten that damages the small intestine. What the antibody tests show, how it is diagnosed, and how it is treated.
- [Cellular senescence](https://longevity-lab.fit/glossary/cellular-senescence): Cellular senescence is when a damaged cell stops dividing for good but stays alive and inflames the tissue around it. Why these cells build up with age.
- [Cholesterol (total)](https://longevity-lab.fit/glossary/cholesterol-total): Total cholesterol is the sum of the cholesterol in all your blood lipoproteins. What the lipid panel reads, the usual bands, and what actually moves it.
- [Chronic stress](https://longevity-lab.fit/glossary/chronic-stress): Chronic stress is a stress response that never switches off: sustained HPA-axis and cortisol activation, how it is gauged and what it does to aging.
- [Chronological age](https://longevity-lab.fit/glossary/chronological-age): Chronological age is the time since your birth, in years. What it measures, why it predicts risk, how it differs from biological age and what can change it.
- [Circadian rhythm](https://longevity-lab.fit/glossary/circadian-rhythm): Circadian rhythm is the body's internal 24-hour clock, set by light and run from the hypothalamus. What it times, why disruption matters, how to reset it.
- [Cognitive age](https://longevity-lab.fit/glossary/cognitive-age): Cognitive age is an estimate, in years, of how old your memory, attention and speed perform against age norms. What it measures and how to read the gap.
- [Cognitive aging](https://longevity-lab.fit/glossary/cognitive-aging): Cognitive aging is the normal, gradual slowing of thinking and recall with age: what is typical, how it differs from dementia, and what protects the brain.
- [Cognitive reserve](https://longevity-lab.fit/glossary/cognitive-reserve): Cognitive reserve is the brain's ability to keep working despite damage: what it means, how researchers measure it by proxy, and what builds it.
- [Cortisol](https://longevity-lab.fit/glossary/cortisol): Cortisol is the adrenal stress hormone that follows a daily rhythm. How it is measured, what a flat curve means, and which habits actually change it.
- [Creatinine](https://longevity-lab.fit/glossary/creatinine): Creatinine is a muscle waste product the kidneys filter out of the blood, and its level is used to estimate GFR. What the test shows and what shifts it.
- [Dementia](https://longevity-lab.fit/glossary/dementia): Dementia is a lasting decline in memory, thinking and judgment that disrupts daily life. What causes it, how it is diagnosed and what lowers the risk.
- [DEXA](https://longevity-lab.fit/glossary/dexa): DEXA is a low-dose X-ray scan that measures bone mineral density and body composition. What it measures, T-score bands, and what changes your result.
- [Diastolic pressure](https://longevity-lab.fit/glossary/diastolic-pressure): Diastolic pressure is the lower blood pressure number: the pressure held in your arteries between heartbeats. What is normal, why it matters, what moves it.
- [DNA methylation](https://longevity-lab.fit/glossary/dna-methylation): DNA methylation is a chemical tag on DNA that switches genes on or off. What it measures, how epigenetic clocks read it, and what actually changes it.
- [DNAm age](https://longevity-lab.fit/glossary/dnam-age): DNAm age is a biological age estimate read from DNA methylation patterns. What it measures, how to read the number, and what actually moves it.
- [DunedinPACE](https://longevity-lab.fit/glossary/dunedinpace): DunedinPACE is an epigenetic clock that measures the pace of aging as a ratio of biological years per calendar year: what it reads and what moves it.
- [Endothelium](https://longevity-lab.fit/glossary/endothelium): The endothelium is the single-cell lining of every blood vessel. What it does, how endothelial function is tested, and what improves or damages it.
- [Epigenetic clock](https://longevity-lab.fit/glossary/epigenetic-clock): An epigenetic clock estimates biological age from DNA methylation patterns. What it measures, how the numbers are reported, and what actually moves it.
- [Epigenetics](https://longevity-lab.fit/glossary/epigenetics): Epigenetics is how chemical marks switch genes on and off without changing the DNA itself. What it covers, how it links to aging, and what shifts it.
- [Estimated biological age](https://longevity-lab.fit/glossary/estimated-biological-age): Estimated biological age is the age a model assigns your body from blood tests and blood pressure: what it measures, how to read it, what changes it.
- [Fat-free mass (FFM)](https://longevity-lab.fit/glossary/fat-free-mass-ffm): Fat-free mass (FFM) is all the body weight that is not fat: muscle, bone, organs and water. What it measures, typical values, and what changes it.
- [Ferritin](https://longevity-lab.fit/glossary/ferritin): Ferritin is the protein that stores iron in your cells; the blood test estimates your iron reserves. What it measures, and why inflammation raises it.
- [Fitness age](https://longevity-lab.fit/glossary/fitness-age): Fitness age is your cardiorespiratory fitness expressed in years: what it measures, how calculators estimate it without a lab test, and what lowers it.
- [Folate](https://longevity-lab.fit/glossary/folate): Folate is vitamin B9, used to build DNA and carry methyl groups. What serum and red cell folate tests show, the usual thresholds, and what depletes it.
- [Genetic age](https://longevity-lab.fit/glossary/genetic-age): Genetic age is the share of your aging and lifespan set by inherited DNA. What it covers, how it differs from biological age, and why genes are not destiny.
- [Gestational diabetes](https://longevity-lab.fit/glossary/gestational-diabetes): Gestational diabetes is high blood glucose first detected in pregnancy. The glucose tolerance test cut-offs, why it matters, and what to do after birth.
- [Glycated hemoglobin (HbA1c)](https://longevity-lab.fit/glossary/glycated-hemoglobin-hba1c): HbA1c (glycated hemoglobin) is the share of hemoglobin with glucose attached: a running average of blood sugar over the past two to three months.
- [GrimAge](https://longevity-lab.fit/glossary/grimage): GrimAge is a second-generation epigenetic clock that estimates mortality risk from DNA methylation in blood: what it reads and what moves the number.
- [Gut microbiome](https://longevity-lab.fit/glossary/gut-microbiome): The gut microbiome is the community of microbes living in your digestive tract, mostly the colon. What it does, how it is tested, and what changes it.
- [HDL](https://longevity-lab.fit/glossary/hdl): HDL is high-density lipoprotein, the particle that carries cholesterol back to the liver. What HDL cholesterol measures, its bands, and what moves it.
- [Healthspan](https://longevity-lab.fit/glossary/healthspan): Healthspan is the part of life lived in good health, free of chronic disease and disability. How healthspan differs from lifespan and what widens the gap.
- [Heart rate zones](https://longevity-lab.fit/glossary/heart-rate-zones): Heart rate zones are pulse ranges used to dose exercise intensity. What the five zones train, how they are calculated, and why the anchor matters.
- [Hemoglobin](https://longevity-lab.fit/glossary/hemoglobin): Hemoglobin is the iron-rich protein in red blood cells that carries oxygen. What the blood test measures, usual adult ranges, and what raises or lowers it.
- [Homocysteine](https://longevity-lab.fit/glossary/homocysteine): Homocysteine is an amino acid made when the body processes methionine. What a raised homocysteine level means, its normal range, and what lowers it.
- [Hormesis](https://longevity-lab.fit/glossary/hormesis): Hormesis is the pattern where a small dose of stress - exercise, heat, cold, fasting - strengthens the body while a large dose harms it. What it means.
- [hs-CRP](https://longevity-lab.fit/glossary/hs-crp): hs-CRP is a high-sensitivity blood test for C-reactive protein, a marker of low-grade inflammation used in cardiovascular risk assessment. What it means.
- [Hyperparathyroidism](https://longevity-lab.fit/glossary/hyperparathyroidism): Hyperparathyroidism is the overproduction of parathyroid hormone by the parathyroid glands. What primary, secondary and tertiary mean, and the lab pattern.
- [Hypothyroidism](https://longevity-lab.fit/glossary/hypothyroidism): Hypothyroidism is an underactive thyroid gland making too little hormone. What the TSH and free T4 pattern shows, why it matters, and how it is treated.
- [IGF-1](https://longevity-lab.fit/glossary/igf-1): IGF-1 (insulin-like growth factor 1) is the hormone that does growth hormone's work. What the blood test shows, why ranges are age-specific, what moves it.
- [Inflammatory markers](https://longevity-lab.fit/glossary/inflammatory-markers): Inflammatory markers are blood tests — CRP, hs-CRP, ESR, fibrinogen, ferritin, IL-6 — showing how much inflammation is active in the body, and why it matters.
- [Insulin](https://longevity-lab.fit/glossary/insulin): Insulin is the pancreatic hormone that moves glucose from blood into cells. What a fasting insulin test shows, why it rises, and what lowers it.
- [Insulin resistance](https://longevity-lab.fit/glossary/insulin-resistance): Insulin resistance is when muscle, fat and liver cells respond poorly to insulin, so the pancreas makes more. What it measures and what changes it.
- [Intermittent fasting](https://longevity-lab.fit/glossary/intermittent-fasting): Intermittent fasting is an eating pattern that alternates set eating windows with periods of no calories. What it is, what trials show, who should avoid it.
- [Iron deficiency](https://longevity-lab.fit/glossary/iron-deficiency): Iron deficiency is a shortage of usable iron that empties your stores long before hemoglobin falls. What ferritin and transferrin saturation reveal.
- [Laboratory tests](https://longevity-lab.fit/glossary/laboratory-tests): Laboratory tests are analyses of blood, urine and other samples that measure a specific substance. What reference ranges mean and how to read a result.
- [Lean muscle mass](https://longevity-lab.fit/glossary/lean-muscle-mass): Lean muscle mass is the weight of your skeletal muscle, counted apart from fat and bone. What it measures, typical values, and why it matters for aging.
- [Longevity](https://longevity-lab.fit/glossary/longevity): Longevity is how long a person or population actually lives, and the science of extending it. How it differs from life expectancy and healthspan.
- [MACE](https://longevity-lab.fit/glossary/mace): MACE, or major adverse cardiovascular events, is the composite trial endpoint counting cardiovascular death, heart attack and stroke as one event.
- [Magnesium](https://longevity-lab.fit/glossary/magnesium): Magnesium is an essential mineral and cofactor in over 300 enzyme reactions. What the blood test shows, normal ranges, deficiency causes and food sources.
- [MCV](https://longevity-lab.fit/glossary/mcv): MCV (mean corpuscular volume) is the average size of your red blood cells. What the blood count measures, usual adult ranges, and what low or high means.
- [Mediterranean diet](https://longevity-lab.fit/glossary/mediterranean-diet): The Mediterranean diet is an eating pattern built on vegetables, legumes, whole grains, olive oil and fish. What it is, how it is scored, why it matters.
- [Metabolic syndrome](https://longevity-lab.fit/glossary/metabolic-syndrome): Metabolic syndrome is a cluster of five risk factors - waist, triglycerides, HDL, blood pressure, glucose - diagnosed when any three occur together.
- [Metabolism](https://longevity-lab.fit/glossary/metabolism): Metabolism is the full set of chemical reactions that turn food into energy and body tissue: what it measures, why it matters for aging, what changes it.
- [Methionine](https://longevity-lab.fit/glossary/methionine): Methionine is an essential sulfur amino acid that begins every protein and supplies SAM for methylation. What it does, where it comes from, why it matters.
- [METS-IR](https://longevity-lab.fit/glossary/mets-ir): METS-IR is an insulin resistance score calculated from fasting glucose, triglycerides, HDL and BMI, with no insulin test needed. How to read it.
- [Mild cognitive impairment (MCI)](https://longevity-lab.fit/glossary/mild-cognitive-impairment-mci): Mild cognitive impairment (MCI) is measurable decline in memory or thinking that does not yet cost independence. How it is diagnosed and what helps.
- [Mitochondria](https://longevity-lab.fit/glossary/mitochondria): Mitochondria are the organelles that turn food and oxygen into ATP, the cell's energy. What they do, why they decline with age, and what actually helps.
- [MTHFR](https://longevity-lab.fit/glossary/mthfr): MTHFR is the gene for the enzyme that activates folate. What the C677T variant does, how it affects homocysteine, and why the result is often over-read.
- [mTOR](https://longevity-lab.fit/glossary/mtor): mTOR is the cell's nutrient sensor that decides between growth and repair. What it does, how food, exercise and rapamycin change it, and why aging cares.
- [Neurodegeneration](https://longevity-lab.fit/glossary/neurodegeneration): Neurodegeneration is the progressive loss and death of neurons. What it is, how it is measured, why it drives dementia, and which levers slow it down.
- [Neuroinflammation](https://longevity-lab.fit/glossary/neuroinflammation): Neuroinflammation is the immune response of brain tissue, run by microglia. How it is measured, why chronic activation matters for brain aging.
- [Neuromotor function](https://longevity-lab.fit/glossary/neuromotor-function): Neuromotor function is how the nervous system controls movement: balance, coordination and motor units. How it is tested and why it predicts healthy aging.
- [Neurons](https://longevity-lab.fit/glossary/neurons): Neurons are the cells that carry and process signals in the brain and nerves. What they are, how they change with age, and what protects them.
- [Osteopenia](https://longevity-lab.fit/glossary/osteopenia): Osteopenia is moderately low bone density, a T-score between -1.0 and -2.5 on a DXA scan. What the number means, why it matters, and what slows the loss.
- [Osteoporosis](https://longevity-lab.fit/glossary/osteoporosis): Osteoporosis is a bone disease in which low density and damaged structure make fractures likely. What a T-score means, why it matters, and what helps.
- [Oxidative stress](https://longevity-lab.fit/glossary/oxidative-stress): Oxidative stress is an imbalance between reactive oxygen species and the body's antioxidant defenses. What it damages, how it is measured, what lowers it.
- [Parathyroid hormone (PTH)](https://longevity-lab.fit/glossary/parathyroid-hormone-pth): Parathyroid hormone (PTH) is the hormone that keeps blood calcium steady. What the test measures, how it is read with calcium, and what raises or lowers it.
- [Perceived stress](https://longevity-lab.fit/glossary/perceived-stress): Perceived stress is how far you judge life to be unpredictable and beyond your control. What the Perceived Stress Scale reads, and why it matters.
- [PhenoAge](https://longevity-lab.fit/glossary/phenoage): PhenoAge is a biological age in years, calculated from nine routine blood markers plus chronological age and fitted to predict mortality risk.
- [Prediabetes](https://longevity-lab.fit/glossary/prediabetes): Prediabetes is blood sugar above normal but below the diabetes threshold. The fasting glucose, OGTT and HbA1c cut-offs, and what moves the numbers back.
- [Processing speed](https://longevity-lab.fit/glossary/processing-speed): Processing speed is how fast the brain takes in information and responds. What tests measure it, why it declines first with age, and what improves it.
- [RDW](https://longevity-lab.fit/glossary/rdw): RDW (red cell distribution width) shows how much your red blood cells vary in size. What the test measures, usual adult ranges, and what a high RDW means.
- [Red blood cells (RBC)](https://longevity-lab.fit/glossary/red-blood-cells-rbc): Red blood cells (RBC) are the oxygen-carrying cells of the blood. What the RBC count on a blood test measures, usual adult ranges, and what moves it.
- [Resting heart rate](https://longevity-lab.fit/glossary/resting-heart-rate): Resting heart rate is how many beats per minute your heart makes at rest. What counts as normal, why a lower pulse tracks fitness, and what moves it.
- [Sarcopenia](https://longevity-lab.fit/glossary/sarcopenia): Sarcopenia is the age-related loss of skeletal muscle mass and strength. What it measures, the cut-offs clinicians use, and how to slow it down.
- [Sirtuins](https://longevity-lab.fit/glossary/sirtuins): Sirtuins are seven NAD+-dependent enzymes, SIRT1 to SIRT7, that link a cell's energy state to gene activity. What they do and what actually changes them.
- [Skeletal muscle mass (SMM)](https://longevity-lab.fit/glossary/skeletal-muscle-mass-smm): Skeletal muscle mass (SMM) is the total weight of the muscle on your skeleton. What it measures, how DXA and bioimpedance read it, and how to keep it.
- [Statins](https://longevity-lab.fit/glossary/statins): Statins are drugs that lower LDL cholesterol by blocking HMG-CoA reductase. What they do, how dose intensity works, the benefits and the side effects.
- [Steatohepatosis](https://longevity-lab.fit/glossary/steatohepatosis): Steatohepatosis, or fatty liver, is fat stored inside liver cells. What it measures, how it is graded, why it matters for longevity and what changes it.
- [Stem cells](https://longevity-lab.fit/glossary/stem-cells): Stem cells are unspecialized cells that renew themselves and rebuild tissue. What they are, why the reserve shrinks with age, and what really works.
- [Stroke](https://longevity-lab.fit/glossary/stroke): Stroke is sudden brain damage from a blocked or bleeding artery: the ischemic and hemorrhagic types, the FAST warning signs, and what lowers the risk.
- [Subcutaneous fat](https://longevity-lab.fit/glossary/subcutaneous-fat): Subcutaneous fat is the fat layer stored just under the skin. What it is, how calipers and DEXA measure it, how it differs from visceral fat, what moves it.
- [Systolic pressure](https://longevity-lab.fit/glossary/systolic-pressure): Systolic pressure is the top blood pressure number, the peak force in your arteries as the heart contracts. What counts as normal and what moves it.
- [Telomerase](https://longevity-lab.fit/glossary/telomerase): Telomerase is the enzyme that rebuilds the telomere caps on chromosomes. Where it is active, why adult cells switch it off, and what it means for aging.
- [Telomeres](https://longevity-lab.fit/glossary/telomeres): Telomeres are the repeating DNA caps at the ends of your chromosomes that shorten as cells divide. How they are measured and why they matter for aging.
- [The Hayflick limit](https://longevity-lab.fit/glossary/the-hayflick-limit): The Hayflick limit is the maximum number of times a normal human cell can divide before it stops for good. What sets it and why it matters for aging.
- [Total protein](https://longevity-lab.fit/glossary/total-protein): Total protein is the combined amount of albumin and globulins in blood serum. What the test measures, its usual range, and what moves it up or down.
- [Triglycerides](https://longevity-lab.fit/glossary/triglycerides): Triglycerides are the main storage fat in the blood, read from a lipid panel. What the number measures, the usual bands, and what actually lowers it.
- [Type 2 diabetes](https://longevity-lab.fit/glossary/type-2-diabetes): Type 2 diabetes is a chronic condition where cells resist insulin and blood glucose stays high. How it is diagnosed, why it shortens life, what changes it.
- [Vascular age](https://longevity-lab.fit/glossary/vascular-age): Vascular age is the age at which the average person's arteries match yours. How it is measured, what the number means and what actually changes it.
- [Visceral fat](https://longevity-lab.fit/glossary/visceral-fat): Visceral fat is the deep abdominal fat stored around the liver, pancreas and intestines. What it is, how it is measured, why it raises risk, how to cut it.
- [Vitamin B12](https://longevity-lab.fit/glossary/vitamin-b12): Vitamin B12 (cobalamin) is the vitamin behind red blood cells and nerve myelin. What the blood test shows, who runs low, and how deficiency is corrected.
- [Vitamin C](https://longevity-lab.fit/glossary/vitamin-c): Vitamin C (ascorbic acid) is an essential vitamin needed for collagen, iron absorption and antioxidant defense. Intake targets, food sources and testing.
- [Vitamin D](https://longevity-lab.fit/glossary/vitamin-d): Vitamin D is a hormone-like nutrient measured in blood as 25-OH D: what the test shows, the ranges labs use, why deficiency matters and how to correct it.
- [VO2max](https://longevity-lab.fit/glossary/vo2max): VO2max is the maximum amount of oxygen your body can use per minute during all-out exercise. What it measures, typical values, and how to raise it.
- [Waist circumference](https://longevity-lab.fit/glossary/waist-circumference): Waist circumference is the tape measurement around your abdomen and a proxy for visceral fat. What the cut-offs mean, and what actually moves the number.
- [Waist-to-height ratio (WHtR)](https://longevity-lab.fit/glossary/waist-to-height-ratio-whtr): Waist-to-height ratio (WHtR) is your waist circumference divided by your height. What it measures, the 0.5 rule, typical bands and what changes it.
- [Zinc](https://longevity-lab.fit/glossary/zinc): Zinc is an essential trace mineral hundreds of enzymes depend on. What a serum zinc test measures, why inflammation lowers it, and what moves your level.

## How to measure

How each marker and score is measured. Index: https://longevity-lab.fit/how-to-measure

- [How an echocardiogram estimates your heart age](https://longevity-lab.fit/how-an-echocardiogram-estimates-your-heart-age): Heart age by echocardiogram: which values from your echo report a model uses, how to read the age gap, and why the scan has to be done in a clinic.
- [How to assess iron deficiency from blood work](https://longevity-lab.fit/how-to-assess-iron-deficiency-from-blood-work): How to assess iron deficiency from blood work: which markers to order — ferritin, transferrin saturation, TIBC, MCV, hemoglobin — and how to read them.
- [How to assess liver fibrosis with FibroTest](https://longevity-lab.fit/how-to-assess-liver-fibrosis-with-fibrotest): How to assess liver fibrosis with FibroTest: the five blood proteins the panel needs, how age and sex adjust the score, and how to read the stage.
- [How to assess peripheral thyroid hormone conversion](https://longevity-lab.fit/how-to-assess-peripheral-thyroid-hormone-conversion): How to assess peripheral thyroid hormone conversion: which blood values you need, how the SPINA-GD estimate of T4-to-T3 conversion works, and how to read it.
- [How to assess thyroid function](https://longevity-lab.fit/how-to-assess-thyroid-function): How to assess thyroid function: which blood markers to order — TSH, free T4 and free T3 — how the feedback loop works, and how to read each pattern.
- [How to assess thyroid hormone sensitivity](https://longevity-lab.fit/how-to-assess-thyroid-hormone-sensitivity): How to assess thyroid hormone sensitivity: the TSH, free T4 and free T3 you need, how TSHI, PTFQI and the free T3/T4 ratio are built, and their limits.
- [How to assess your body composition](https://longevity-lab.fit/how-to-assess-your-body-composition): How to measure body composition: the tape and scale readings you need, how body-fat percentage, fat-free mass, FFMI and SMI are worked out, and their limits.
- [How to assess your body fat percentage](https://longevity-lab.fit/how-to-assess-your-body-fat-percentage): How to assess your body fat percentage: the tape measurements you need, how the Navy and BMI-based estimates work, and what the number cannot tell you.
- [How to assess your risk of developing diabetes](https://longevity-lab.fit/how-to-assess-your-risk-of-developing-diabetes): How to assess diabetes risk: the waist, weight and lifestyle answers a risk score needs, plus the fasting glucose and HbA1c bands that confirm prediabetes.
- [How to calculate heart age with QRISK](https://longevity-lab.fit/how-to-calculate-heart-age-with-qrisk): How to calculate heart age with QRISK: the blood pressure, cholesterol and history inputs the model needs, how the number is built, and what it cannot see.
- [How to calculate your fitness age](https://longevity-lab.fit/how-to-calculate-your-fitness-age): How to calculate your fitness age: the inputs you need, how a non-exercise estimate of VO2max becomes an age, and what the number cannot tell you.
- [How to calculate your metabolic index](https://longevity-lab.fit/how-to-calculate-your-metabolic-index): How to calculate your metabolic index (MI): the fasting triglycerides, glucose and HDL you need, how the score is read, and where it misleads you.
- [How to calculate your PhenoAge from a blood test](https://longevity-lab.fit/how-to-calculate-your-phenoage-from-a-blood-test): How to calculate PhenoAge: the nine blood markers you need, which panels they come from, how the score is built, and how to read the gap against your age.
- [How to check yourself for metabolic syndrome](https://longevity-lab.fit/how-to-check-yourself-for-metabolic-syndrome): How to check yourself for metabolic syndrome: the five criteria - waist, blood pressure, fasting glucose, triglycerides and HDL - and what counts as abnormal.
- [How to choose a biological age test](https://longevity-lab.fit/how-to-choose-a-biological-age-test): How to choose a biological age test: what a questionnaire, a blood panel, a methylation kit or a clinic scan each need, and how to read the age gap.
- [How to classify liver injury with the R-factor](https://longevity-lab.fit/how-to-classify-liver-injury-with-the-r-factor): How to classify liver injury with the R-factor: the two blood values you need, ALT and alkaline phosphatase, and how to read hepatocellular vs cholestatic.
- [How to detect masked hypertension](https://longevity-lab.fit/how-to-detect-masked-hypertension): How to detect masked hypertension: the home cuff and 24-hour ambulatory readings you need, the out-of-office thresholds, and what the test misses.
- [How to estimate blood age with the Bortz method](https://longevity-lab.fit/how-to-estimate-blood-age-with-the-bortz-method): How to estimate blood age with the Bortz method: the lab values you need, how the UK Biobank model turns them into years, and how to read the gap.
- [How to estimate insulin resistance with METS-IR](https://longevity-lab.fit/how-to-estimate-insulin-resistance-with-mets-ir): How to estimate insulin resistance with METS-IR: the fasting labs you need, what each input does to the score, and why there is no single cut-off.
- [How to estimate liver fat with the NAFLD Liver Fat Score](https://longevity-lab.fit/how-to-estimate-liver-fat-with-the-nafld-liver-fat-score): How to estimate liver fat with the NAFLD Liver Fat Score: the fasting insulin, AST and ALT values you need, what each input does, and where it misleads.
- [How to estimate metabolic age from lifestyle and body composition](https://longevity-lab.fit/how-to-estimate-metabolic-age-from-lifestyle-and-body-composition): How to estimate metabolic age at home from height, weight, waist, body-fat percentage and lifestyle: what each input does and how to read the gap.
- [How to estimate physical form age from VO2max](https://longevity-lab.fit/how-to-estimate-physical-form-age-from-vo2max): How to estimate physical form age from VO2max: the resting heart rate, age and training details a non-exercise model needs, and how to read the result.
- [How to estimate vascular age with the ADVANTAGE score](https://longevity-lab.fit/how-to-estimate-vascular-age-with-the-advantage-score): How to estimate vascular age with the ADVANTAGE score: the six inputs it needs, what each one does to the number, and how to read the years it gives back.
- [How to estimate visceral fat with the Lipid Accumulation Product](https://longevity-lab.fit/how-to-estimate-visceral-fat-with-the-lipid-accumulation-product): How to measure the Lipid Accumulation Product (LAP): the waist and fasting triglyceride numbers you need, how the score is built, and how to read it.
- [How to estimate your biological age without lab tests](https://longevity-lab.fit/how-to-estimate-your-biological-age-without-lab-tests): How to estimate biological age without lab tests: the height, weight, waist and hip measurements an anthropometric age model needs, and how to read it.
- [How to estimate your cognitive age](https://longevity-lab.fit/how-to-estimate-your-cognitive-age): How to estimate your cognitive age: which memory, attention and speed tasks the test uses, what you need to take one, and how to read the year gap.
- [How to estimate your heart age](https://longevity-lab.fit/how-to-estimate-your-heart-age): Heart age: how to estimate it from an AI-read 12-lead ECG or from your standard risk factors, what each route needs, and how to read the age gap.
- [How to estimate your mental age](https://longevity-lab.fit/how-to-estimate-your-mental-age): How to estimate your mental age at home: what a 12-question mental age test asks, how the five trait dimensions move the score, and how to read the gap.
- [How to estimate your metabolic age without lab tests](https://longevity-lab.fit/how-to-estimate-your-metabolic-age-without-lab-tests): How to estimate metabolic age with no lab tests: the four inputs you need, how resting calorie burn becomes an age, and what the number cannot tell you.
- [How to interpret your body mass index](https://longevity-lab.fit/how-to-interpret-your-body-mass-index): How to measure and interpret your body mass index at home: taking height and weight correctly, the WHO BMI categories, and what BMI cannot tell you.
- [How to measure thyroid secretory capacity with SPINA-GT](https://longevity-lab.fit/how-to-measure-thyroid-secretory-capacity-with-spina-gt): How to measure thyroid secretory capacity with SPINA-GT: the blood tests you need, how TSH and free T4 become a pmol/s capacity, and how to read it.
- [How to measure vascular age with flow-mediated dilation](https://longevity-lab.fit/how-to-measure-vascular-age-with-flow-mediated-dilation): How to measure vascular age with flow-mediated dilation: what an FMD ultrasound scan involves, what else you need, and how to read the %FMD result.
- [How to measure your waist-to-height ratio](https://longevity-lab.fit/how-to-measure-your-waist-to-height-ratio): How to measure your waist-to-height ratio at home: which tape landmark to use, how to measure height, and how to read the ratio against the 0.5 rule.
- [How to measure your waist-to-hip ratio](https://longevity-lab.fit/how-to-measure-your-waist-to-hip-ratio): How to measure your waist-to-hip ratio at home: where to place the tape at the waist and hips, the WHO cut-offs for men and women, and what WHR misses.
- [How to read a liver stiffness score](https://longevity-lab.fit/how-to-read-a-liver-stiffness-score): How to read a liver stiffness score: the elastography scan, the blood values that stand in for it, what each input does, and where the number misleads.
- [How to read your blood pressure category](https://longevity-lab.fit/how-to-read-your-blood-pressure-category): How to read your blood pressure category: the cuff and technique you need, the ACC/AHA stages from normal to stage 2, and what a reading cannot tell you.
- [How to read your BUN to creatinine ratio](https://longevity-lab.fit/how-to-read-your-bun-to-creatinine-ratio): How to read your BUN to creatinine ratio: the two blood values you need, why units matter, and what a high or low urea-to-creatinine ratio points to.
- [How to read your glomerular filtration rate](https://longevity-lab.fit/how-to-read-your-glomerular-filtration-rate): How to measure your glomerular filtration rate: which blood tests you need, how the CKD-EPI equations turn them into eGFR, and how to read the result.
- [How to rule out advanced fibrosis with the SAFE score](https://longevity-lab.fit/how-to-rule-out-advanced-fibrosis-with-the-safe-score): How to rule out advanced fibrosis with the SAFE score: the blood values you need, what age, BMI, diabetes, AST/ALT, globulin and platelets each do.
- [How to run a comprehensive thyroid assessment](https://longevity-lab.fit/how-to-run-a-comprehensive-thyroid-assessment): How to run a comprehensive thyroid assessment: which blood values to order — TSH, free T4, free T3, thyroid antibodies — and how to read each layer.
- [How to screen for fatty liver with the Fatty Liver Index](https://longevity-lab.fit/how-to-screen-for-fatty-liver-with-the-fatty-liver-index): How to screen for fatty liver with the Fatty Liver Index: the BMI, waist, triglyceride and GGT values you need, how the FLI score works, and how to read it.
- [How to screen for fatty liver with the Hepatic Steatosis Index](https://longevity-lab.fit/how-to-screen-for-fatty-liver-with-the-hepatic-steatosis-index): How to measure the Hepatic Steatosis Index (HSI): the ALT, AST, BMI, sex and diabetes inputs you need, how the score is built, and how to read it.
- [How to screen for fibrotic NASH with the FNI](https://longevity-lab.fit/how-to-screen-for-fibrotic-nash-with-the-fni): How to screen for fibrotic NASH with the FNI: the three blood values you need (AST, HbA1c, HDL), what each does to the score, and what it cannot say.
- [How to screen for hidden deficiencies](https://longevity-lab.fit/how-to-screen-for-hidden-deficiencies): How to screen for hidden deficiencies: a history and symptom triage first, then a blood panel led by ferritin, 25-hydroxyvitamin D, B12 and magnesium.
- [How to screen for hidden thyroid problems](https://longevity-lab.fit/how-to-screen-for-hidden-thyroid-problems): How to screen for hidden thyroid problems: a symptom questionnaire that shows a hypo- or hyperthyroid lean, then TSH and free T4 from a lab to confirm it.
- [How to screen for liver fibrosis with FIB-4](https://longevity-lab.fit/how-to-screen-for-liver-fibrosis-with-fib-4): How to screen for liver fibrosis with FIB-4: the blood values you need (age, AST, ALT, platelets), what each does to the score, and how to read the bands.
- [How to screen for liver fibrosis with the NFS score](https://longevity-lab.fit/how-to-screen-for-liver-fibrosis-with-the-nfs-score): How to screen for liver fibrosis with the NFS score: the age, BMI, diabetes status, AST, ALT, platelet and albumin values you need, and how to read it.
- [How to spot hidden calcium deficiency](https://longevity-lab.fit/how-to-spot-hidden-calcium-deficiency): How to spot hidden calcium deficiency: a symptom, diet and risk questionnaire first, then a blood panel of calcium, albumin, vitamin D and PTH to confirm.
- [How to spot hidden iron deficiency](https://longevity-lab.fit/how-to-spot-hidden-iron-deficiency): How to spot hidden iron deficiency: which symptoms justify a test, why ferritin falls first, and which blood markers confirm it before anemia shows.
- [How to tell alcoholic from non-alcoholic liver disease](https://longevity-lab.fit/how-to-tell-alcoholic-from-non-alcoholic-liver-disease): How to tell alcoholic from non-alcoholic liver disease: the ANI index uses the AST/ALT ratio, MCV, BMI and sex, and here is what each value adds.

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