What 21 Longevity Biomarkers Does Nuvo Track and Why Each One Was Chosen
Nuvo tracks 21 longevity biomarkers — five from blood tests and sixteen from wearable data — to calculate a daily biological age score. This article covers exactly which biomarkers those are, what each one measures, and why it belongs in a biological age calculation.
Written by the Nuvo Longevity editorial team at Firefly Labs LLC.
You've run the blood panel. You've worn the Apple Watch for months. You have numbers — HbA1c, HRV, resting heart rate, sleep stages — but no coherent picture of what they add up to.
That's the problem Nuvo was built to solve. The app pulls 21 longevity biomarkers from two sources — wearable data and blood test results — and collapses them into a single daily biological age score. This article covers exactly which biomarkers those are, what each one measures, and why it belongs in a biological age calculation rather than a standard annual checkup.
Why 21 Biomarkers, and Why These Specific Ones
Most health apps track what's easy to measure, not what's most predictive of how you're aging. Step count is easy. Resting heart rate is easy. Neither one tells you much about whether your cells are aging faster than your birth year suggests.
Biological age research points to a different set of signals — markers tied to metabolic function, cardiovascular efficiency, systemic inflammation, and cellular stress. Nuvo's 21 biomarkers were selected because they collectively cover those mechanisms, not because they're the most common fields on a lab requisition form.
The 21 split into two categories: blood biomarkers you enter from a lab result, and wearable biomarkers your Apple Watch, Oura Ring, or Garmin captures continuously.
The Blood Biomarkers: What Your Lab Results Reveal About Aging
Blood tests capture biological processes no wearable can detect. Each of the five blood biomarkers Nuvo integrates reflects a distinct aging mechanism.
HbA1c (Glycated Hemoglobin)
HbA1c measures the percentage of hemoglobin that has bonded with glucose over the past two to three months. It's a longitudinal snapshot of blood sugar control. A single fasting glucose reading captures one moment. HbA1c captures a pattern.
Chronically elevated HbA1c accelerates glycation — a process where excess glucose binds to proteins and degrades them. That damage accumulates in blood vessels, nerves, and organs. The optimal range sits below 5.7%. Values between 5.7% and 6.4% indicate prediabetes; 6.5% and above meets the diagnostic threshold for type 2 diabetes. Because glycation is a direct driver of accelerated aging, HbA1c carries significant weight in any biological age calculation.
Fasting Glucose
Where HbA1c shows the trend, fasting glucose shows the current state. A reading above 100 mg/dL signals impaired glucose regulation even before HbA1c climbs out of range.
The two markers together are more informative than either alone. You can have a normal fasting glucose and a creeping HbA1c, or the reverse. Nuvo uses both because the combination catches what a single metabolic marker misses.
HDL Cholesterol
HDL is often labeled "good" cholesterol, but that framing undersells what it actually does. HDL particles actively remove cholesterol from arterial walls and transport it back to the liver for processing. Low HDL correlates with increased cardiovascular risk and, more broadly, with the kind of metabolic dysfunction that drives accelerated biological aging.
The longevity-relevant threshold isn't simply "not low" — it's actively high. HDL above 60 mg/dL is associated with reduced cardiovascular risk. Below 40 mg/dL in men and 50 mg/dL in women, risk climbs meaningfully.
CRP (C-Reactive Protein)
CRP is a protein the liver produces in response to systemic inflammation. Elevated CRP doesn't point to a single cause — it reflects a general state of chronic low-grade inflammation that research consistently links to accelerated cellular aging, cardiovascular disease, and metabolic dysfunction.
High-sensitivity CRP (hs-CRP) below 1.0 mg/L is considered low risk. Above 3.0 mg/L, the inflammatory burden is significant enough to factor materially into biological age. CRP also responds relatively quickly to lifestyle changes, which is why tracking it over time — rather than treating it as a one-time number — matters.
Creatinine
Creatinine is a waste product of muscle metabolism that the kidneys filter from the blood. Elevated creatinine signals reduced kidney filtration efficiency, which the estimated glomerular filtration rate (eGFR) quantifies more precisely.
Kidney function declines gradually with age, and that decline accelerates with chronic hypertension, diabetes, and inflammation — the same conditions that drive biological aging more broadly. Including creatinine captures the renal aging axis that cardiovascular and metabolic markers alone don't cover.
The Wearable Biomarkers: What Continuous Data Adds
Blood tests are snapshots taken weeks or months apart. Wearable data is continuous. The two streams are complementary — blood markers show what's happening at the cellular and systemic level; wearable markers show how your body is performing and recovering day to day.
Nuvo integrates wearable data from Apple Watch, Oura Ring, and Garmin via HealthKit. These biomarkers span cardiovascular fitness, recovery, sleep quality, and activity.
VO2 Max
VO2 max is the maximum rate at which your body can consume oxygen during exercise. It's the single strongest predictor of all-cause mortality in large longitudinal studies — more predictive than most blood markers in isolation.
A one-unit increase in VO2 max corresponds to a measurable reduction in cardiovascular mortality risk. Low VO2 max, conversely, is associated with biological ages significantly older than chronological age. Apple Watch estimates VO2 max using heart rate and GPS data during outdoor walks and runs, updating with each qualifying workout.
Resting Heart Rate
A lower resting heart rate generally indicates a more efficient cardiovascular system — the heart pumps more blood per beat, so it needs fewer beats per minute to maintain circulation.
Resting heart rate above 80 bpm is associated with increased cardiovascular risk. Below 60 bpm is typical for fit individuals. Because it responds to sleep, stress, illness, and training load, resting heart rate functions as a daily signal of cardiovascular and autonomic health, not just a fitness metric.
Heart Rate Variability (HRV)
HRV measures the variation in time between consecutive heartbeats. A higher HRV indicates a well-regulated autonomic nervous system — one that shifts efficiently between stress and recovery states.
HRV drops with age, chronic stress, poor sleep, and systemic inflammation. It rises with aerobic fitness, good recovery, and consistent stress management. Because HRV integrates signals from multiple body systems, it functions as a composite indicator of physiological resilience. It's often the first marker to signal something is off, before anything else changes.
Sleep Duration
Consistent sleep below seven hours per night is associated with accelerated telomere shortening, elevated inflammatory markers, impaired glucose regulation, and reduced cognitive performance — all mechanisms that drive biological aging.
The relationship isn't linear in the other direction either. Consistently sleeping more than nine hours without a medical explanation can signal underlying health issues. Nuvo tracks sleep duration as reported by your wearable, which captures actual sleep time rather than time in bed.
Sleep Quality (Sleep Stages)
Duration matters, but so does architecture. Deep sleep — slow-wave sleep — drives physical recovery, cellular repair, and growth hormone release. REM sleep consolidates memory and supports emotional regulation. Fragmented sleep that lacks adequate deep and REM stages leaves you biologically under-recovered even when total hours look fine.
Wearables estimate sleep stages through heart rate and movement data. Accuracy varies by device, but the longitudinal pattern — whether your deep and REM percentages are trending up or down — is more informative than any single night's reading.
Respiratory Rate During Sleep
Resting respiratory rate during sleep is a sensitive indicator of autonomic stress, early illness, and cardiovascular strain. Elevated nighttime respiratory rate often precedes other visible symptoms of overtraining, infection, or metabolic stress by 24 to 48 hours.
Modern wearables measure this through photoplethysmography (PPG) sensors. Most people never look at this number on their own — which is exactly why including it in a composite biological age score adds signal that a manual review of health data would miss.
Blood Oxygen Saturation (SpO2)
SpO2 measures the percentage of hemoglobin carrying oxygen in the blood. Normal values sit between 95% and 100%. Consistently low SpO2 during sleep can indicate sleep apnea, a condition strongly associated with cardiovascular aging, metabolic dysfunction, and cognitive decline.
SpO2 is particularly useful as a screening signal. A single low overnight reading isn't diagnostic, but a pattern of values below 94% warrants clinical follow-up. Chronic hypoxia — even mild — accelerates cellular aging through oxidative stress, which is why it belongs in the biological age calculation.
Active Energy Expenditure
Total calories burned through intentional movement reflects both exercise volume and metabolic efficiency. Consistently low active energy expenditure is associated with reduced insulin sensitivity, lower VO2 max, and higher resting inflammatory markers.
Active energy is distinct from total calories burned, which includes basal metabolic rate. Tracking it specifically captures whether you're moving enough to generate the physiological adaptations that slow biological aging.
Exercise Minutes
Raw exercise time, independent of intensity, contributes to biological age calculations because consistency matters as much as peak effort. Meeting the widely referenced threshold of 150 minutes of moderate-intensity activity per week is associated with meaningful reductions in all-cause mortality risk.
Nuvo tracks exercise minutes from your wearable and integrates them alongside intensity data to give a fuller picture of weekly training load.
Stand Hours / Movement Breaks
Prolonged sitting is an independent risk factor for cardiovascular disease and metabolic dysfunction — independent of whether you exercise. Someone who runs 45 minutes in the morning and sits for 10 hours afterward still accumulates metabolic risk from that sedentary time.
Stand hours and movement break data from Apple Watch capture whether you're breaking up sedentary periods throughout the day. This is the gap that exercise-only tracking misses.
Steps
Step count is the most basic wearable metric, but it earns its place in a biological age model because it correlates with overall physical activity across the full day — not just during workouts. Consistently low step counts signal low habitual movement, which compounds with other sedentary indicators.
The longevity-relevant threshold in research literature sits around 7,000 to 10,000 steps per day, where risk reduction plateaus for most populations.
Cardio Fitness Recovery (Heart Rate Recovery)
Heart rate recovery — how quickly your heart rate drops in the first minute after peak exercise — is a direct measure of autonomic nervous system efficiency and cardiovascular fitness. Faster recovery correlates with lower cardiovascular mortality risk and a younger functional fitness age.
This marker requires an active workout to generate, but it's one of the more objective cardiovascular aging signals available from consumer wearables.
Workout Frequency
How often you train, independent of duration or intensity, captures training consistency. The biological adaptations from exercise — improved insulin sensitivity, mitochondrial density, cardiovascular efficiency — require regular stimulus to maintain. Gaps in workout frequency show up in other markers within days.
Nuvo tracks workout frequency through HealthKit workout records, covering strength training, cardio, and other logged activities.
Body Temperature Deviation
Baseline body temperature and deviations from that baseline reflect immune activity, hormonal cycles, and recovery status. Elevated temperature during sleep often precedes illness symptoms. Consistent elevation without illness can indicate chronic stress or inflammatory load.
Oura Ring and some Apple Watch models track wrist skin temperature continuously. Nuvo uses deviation from your personal baseline rather than absolute temperature, which makes this marker more sensitive to individual-level changes.
Mindful Minutes / Stress Management
Chronic psychological stress drives cortisol dysregulation, which accelerates biological aging through multiple pathways — elevated inflammation, impaired sleep, reduced HRV, and accelerated telomere shortening. Mindful minutes logged through Apple Watch or the Nuvo app reflect active stress management practices.
This marker doesn't capture stress directly. It captures the behavioral response to stress. That distinction matters. You can't always control stressors, but you can track whether you're consistently doing something about them.
How the 21 Biomarkers Combine Into One Score
No single biomarker tells the full story. HbA1c tells you about metabolic aging but nothing about cardiovascular fitness. VO2 max tells you about aerobic capacity but nothing about systemic inflammation. HRV tells you about recovery status but nothing about kidney function.
The value of Nuvo's approach is the integration. Nuvo Intelligence, the app's on-device AI coach, weights these 21 biomarkers against each other to produce a single daily biological age score. When a blood marker moves out of range, the score reflects it. When HRV improves after a consistent week of sleep and recovery, the score reflects that too.
All of this computation happens on your device. No data leaves your phone. No Nuvo account is required. The app processes everything locally with encrypted storage — which means the most sensitive health data you own stays under your control.
If you're comparing this to platforms like InsideTracker (which costs $489 or more in year one and operates through a web dashboard) or WHOOP (which requires proprietary hardware at $199 to $359 per year and doesn't integrate blood biomarkers), the difference isn't just price. It's the feedback loop. Nuvo gives you a daily score that updates as your habits change, not a quarterly report that arrives after the fact. You can see how that plays out in the Nuvo vs InsideTracker breakdown and the Nuvo vs WHOOP comparison.
What to Do With Out-of-Range Biomarkers
Knowing which biomarkers are pulling your biological age up is only useful if you know what to do about them. Nuvo Intelligence generates personalized nutrition and supplement protocols tied specifically to out-of-range markers — not generic wellness advice, but targeted recommendations based on your actual numbers.
Recovery interventions — sauna, cold plunge, breathwork, meditation, red light therapy, massage — are logged directly in the app, so you can observe whether specific practices are moving your score over time. That feedback loop is what separates tracking from acting.
If you're new to biological age as a concept and want a foundation before diving into the biomarkers, the beginner's guide to biological age covers the core framework.
The Biomarker Selection Logic
Every one of the 21 biomarkers Nuvo tracks connects to a documented aging mechanism — metabolic dysfunction, cardiovascular decline, systemic inflammation, autonomic dysregulation, or cellular stress. None were included because they're easy to measure. Several — CRP, creatinine, HbA1c — require deliberate action to obtain from a lab. That friction is worth it because blood markers capture biological processes that no wearable can detect.
The combination is what matters. Wearable data without blood context misses the metabolic and inflammatory picture. Blood data without daily wearable context misses how your body is actually performing and recovering. Together, they give you something you can act on.
You can explore the full app and see how the score works at nuvolongevity.com.
Frequently Asked Questions
What are the 21 longevity biomarkers Nuvo tracks?
Nuvo tracks five blood biomarkers — HbA1c, fasting glucose, HDL cholesterol, CRP, and creatinine — alongside 16 wearable biomarkers including VO2 max, HRV, resting heart rate, sleep duration, sleep quality, respiratory rate, SpO2, active energy, exercise minutes, stand hours, steps, heart rate recovery, workout frequency, body temperature deviation, and mindful minutes. Together these cover the metabolic, cardiovascular, inflammatory, and recovery dimensions of biological aging.
Why does Nuvo use both blood tests and wearable data?
Blood tests capture biological processes — glycation, inflammation, kidney function, lipid metabolism — that wearables cannot detect. Wearable data captures daily cardiovascular performance, sleep quality, and recovery. Neither source alone gives a complete picture of how you're aging. The combination is what makes the biological age score meaningful rather than a proxy for fitness level.
How often does the biological age score update?
The score updates daily as new wearable data arrives and as you log habits and interventions. Blood biomarkers update whenever you enter new lab results. That daily cycle is what allows you to observe whether specific interventions — sauna, cold plunge, sleep improvements — are actually moving your score.
Do I need to get blood tests regularly to use Nuvo?
No. The app functions with wearable data alone, but the biological age score becomes more complete when blood biomarkers are included. You can enter lab results whenever you have them — from a routine annual physical, a direct-to-consumer panel, or any lab order. No minimum testing frequency is required.
Is my health data shared with Nuvo or any third party?
No. All computation runs on-device with encrypted storage. No Nuvo account is required, and no health data is transmitted to Nuvo's servers or sold to third parties. This applies to both wearable data and blood test results you enter manually.
How does Nuvo's biomarker approach compare to InsideTracker or Function Health?
InsideTracker uses approximately 40 blood biomarkers but has no real-time wearable feedback loop and costs $489 or more in year one including lab fees. Function Health tests 160-plus biomarkers twice per year at $499 annually but has no wearable integration and no daily biological age score. Nuvo combines blood and wearable data into a daily score at $2.08 per month billed annually, running on hardware you already own.
What happens when a biomarker is out of range?
Nuvo Intelligence generates personalized nutrition and supplement protocols tied to out-of-range markers. The app also lets you log recovery interventions — sauna, cold plunge, breathwork, and others — so you can track whether specific habits are moving the affected biomarkers and your overall biological age score over time.