Guides · Longevity & Biological Age
The Longevity Guide: measure your ageing, then slow it
Longevity is no longer guesswork. A standard blood panel, a 12-minute run and a barbell tell you more about your ageing trajectory than any wellness quiz — and every one of those numbers is trainable.
This guide collects everything we have published on measuring and improving healthspan: biological age scoring, the mortality data behind VO2max and strength, and the habits that actually move the needle.
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Read the full series
Part 1
PhenoAge explained — what your bloods say about your real age
PhenoAge turns nine standard blood markers into a single number: how old your body is actually functioning. Here is how it works and how to lower it.
Part 2
I calculated my death-risk from 9 blood markers — here’s the formula
Nine markers on an ordinary blood panel can be combined into a "phenotypic age" that predicts mortality better than the candles on your birthday cake. Here is what each one is, and how the PhenoAge formula turns them into a number.
Part 3
The 4 numbers that predict your next 10 years better than your doctor’s checkup
A standard annual checkup misses the metrics that actually forecast your next decade. Here are the four numbers with the strongest predictive evidence — and, crucially, all four are trainable.
Part 4
VO2max is the strongest mortality predictor we have. Here is why.
A landmark 2018 Cleveland Clinic study found the mortality gap between low-fit and elite-fit is larger than between smokers and non-smokers. VO2max is the metric behind it.
Part 5
How to raise your VO2max by one MET (and why that’s a 12% mortality drop)
A single MET of extra fitness is linked to a double-digit fall in mortality risk — one of the best returns in all of health. Here is exactly how to train for it, and how long it takes.
Part 6
"How many good years do I have left?" The composite longevity score
No single marker captures healthspan. Misi blends your biomarkers, fitness and trends into one composite longevity score — and a trajectory horizon you can actually influence.
Part 7
"Am I aging faster than the calendar?" Your Fitness Age Trajectory
Two people the same age can have bodies a decade apart in function. Misi turns your fitness data into a Fitness Age — and, more importantly, shows which direction it is moving.
Part 8
Strength is a vital sign — why your 1RM tracks your lifespan
Muscular strength is one of the most powerful predictors of how long you will live — rivalling blood pressure and smoking. Here is the evidence, and why Misi treats your strength as a longevity metric.
Part 9
Protein, muscle and a longer life — why skeletal muscle is your retirement fund
Muscle is not just for the gym. It is metabolic reserve, fall protection and one of the strongest predictors of how well you age. And protecting it means raising your protein target as you get older, not lowering it.
Part 10
Beyond PhenoAge: the longevity panel Misi reads from your bloods
One blood panel contains far more than a cholesterol number. Misi extracts cardiovascular, kidney, metabolic and inflammatory risk signals and forecasts where they are heading.
Part 11
The daily habits that actually move the needle on longevity
The science on lifespan keeps pointing back to a short list of unglamorous daily habits. Here is what the evidence supports — and how Misi helps you make them stick.
Part 12
Semaglutide and biological aging: what a new HIV cohort study found
Ozempic and Wegovy are known for weight loss. A 2026 study in adults with HIV — a population with unusually high chronic inflammation — found signs the same drug class may also slow the pace of biological aging itself.
Part 13
Researchers tracked 147,000 people for 30 years. Here is the strength training "sweet spot" they found.
A three-decade cohort study puts a number on something trainers have argued about for years: how much strength training is actually enough for a longevity benefit — and the answer is a lot less than most gym routines assume.
Part 14
Why museums, concerts and theatre nights show up in your biological age
A 2026 study linking cultural activity to biological aging markers sounds like a stretch — until you consider what it is actually proxying for: social engagement, novelty, movement and stress reduction, all bundled into one measurable habit.
Part 15
The gene variant behind families who seem to age more slowly
Some families reliably produce members who live active, disease-free lives into their 90s and beyond. A 2026 genetics study of exceptionally long-lived families points to a shared variant that appears to keep chronic inflammation in check.
Part 16
Scientists found a hidden switch behind aging cells — and it may be reversible
A 2026 cell-biology study identifies a decline in a little-discussed membrane fat, phosphatidylcholine, as a driver of mitochondrial aging — and shows that restoring it can bring aged cells’ energy production back toward youthful levels.
Part 17
Nearly half of older adults get sharper or stronger with age, not weaker
A 12-year Yale study of more than 11,000 older Americans found that 45% improved cognitively, physically, or both — and the strongest predictor wasn’t health status at baseline. It was how positively they viewed their own aging.
Part 18
Osteopenia: the bone-loss condition affecting ~40% of adults that shows no symptoms
Around 40% of adults worldwide have osteopenia — meaningfully reduced bone density — and most have no idea until a fracture or scan reveals it. Here’s what actually slows or partially reverses it, and why it isn’t just "early osteoporosis."
Part 19
People who live past 100 share a distinct blood chemistry "fingerprint," study finds
A study of the New England Centenarian Study found that people who live past 100 have a distinct pattern of bile acids and steroids in their blood — different from ordinary aging and linked to a lower risk of death.
Part 20
NAD+ boosters: what nicotinamide riboside and NMN actually do in humans, according to the trials
A randomised trial found that 12 weeks of NMN raised blood NAD+ levels and modestly improved walking speed and sleep quality in older adults — but the wider body of human trials on NAD-precursor supplements is far more mixed than the marketing around them suggests.
Part 21
What actually slows your epigenetic clock? A landmark trial has an answer — and it isn’t a supplement alone
A post-hoc analysis of the DO-HEALTH trial — co-authored by Steve Horvath, inventor of the epigenetic clock — found that vitamin D, omega-3 and a simple home exercise program each independently slowed biological aging by DNA methylation clocks, with the largest effect when all three were combined.
Part 22
Protecting immune function as you age: what actually moves the needle, according to a controlled trial
A randomised trial found that months of cardiovascular exercise training extended how long older adults stayed protected after a flu vaccine — one of the few controlled human trials showing exercise can measurably improve an aging immune system’s real-world performance.
Part 23
Rapamycin plus exercise in older adults: what a real randomised trial found
Rapamycin is one of the most talked-about longevity drugs, often paired with exercise in biohacker protocols. A randomised, double-blind, placebo-controlled trial tested that combination directly in older adults — and the result complicates the hype.
Stop reading. Start measuring.
Misi turns everything in this guide into your own numbers — blood work parsed, plans built, and both adjusted weekly from the data you log. 7-day free trial.
Frequently asked
What is the most accurate way to measure biological age?
PhenoAge (Levine 2018) is the best-validated measure available from a standard blood panel. It combines nine common markers — albumin, creatinine, glucose, CRP, lymphocyte %, MCV, RDW, alkaline phosphatase and white cell count — into a phenotypic age that predicts 10-year mortality better than chronological age.
What single metric matters most for lifespan?
Cardiorespiratory fitness (VO2max) is the strongest modifiable mortality predictor we have — going from low to even below-average fitness cuts all-cause mortality risk roughly in half (Mandsager 2018). Muscle strength is the second pillar.
Can biological age actually be reversed?
The inputs to PhenoAge — inflammation (CRP), fasting glucose, and blood-count markers — all respond to training, nutrition and sleep within months. Members typically re-test quarterly to track the trend.