METs vs MET-h
Methodology — not a citation, this is how Verve computes it
Video walkthrough — METs vs MET-h
In production, coming soon
METs — how hard
A Metabolic Equivalent of Task (MET) is the energy your body uses per kg of body weight per minute, relative to rest. 1 MET = sitting quietly, using 3.5 mL of O₂/kg/min. Every activity — walking, running, lifting — gets a METs value showing how many times harder it is than sitting still.
MET-h — how much
MET-hours (MET-h) multiply intensity by time:METs × hours. It's the session's training volume, not its intensity. 1 MET-h ≈ 1 kcal burned per kg of body weight (the energy cost of one hour at rest, scaled by your weight) — so MET-h isn't the same number for everyone at the same intensity.
Worked example
A 36-minute strength session averaging 3.4 METsis classified moderate intensity (it's the METs value that sets the label). Its volume is 3.4 × 0.6 hours (36 min) =2.0 MET-h — a completely separate number answering "how much," not "how hard."
Same minutes, different MET-h
WHO/AHA define weekly dose in minutes — but two people hitting the same minutes at different intensities log very different volume:
METs tells you how intense an activity is; MET-h tells you how much of it you did. Verve computes both for every logged and background activity — METs decides its light/moderate/vigorous label, MET-h is its training volume.
Cardiorespiratory Fitness & MET
Why Verve treats CRF as the headline metric, VO₂Max as secondary
Video walkthrough — Cardiorespiratory Fitness
In production, coming soon
Ages 18–39: ACSM / Cooper Institute adult VO₂Max norms (1997), converted to METs.Ages 40+: Cleveland Clinic treadmill data (Mandsager 2018, 122,007 patients). Both use the same 5-tier system (Low → Elite) — Verve automatically selects the correct source based on your profile age.
33 studies, 102,980 participants. Each 1 MET improvement in CRF capacity is associated with a 13% reduction in all-cause mortality and 15% in cardiovascular mortality. Achieving 7.9 MET-hours/week is linked to substantially reduced cardiovascular mortality.
122,007 patients. Being below vs above average CRF carries the same mortality risk as smoking or diabetes. Low to Elite CRF shows a 5-fold difference in all-cause mortality. Verve uses this data for ages 40+ and ACSM/Cooper Institute normative data for ages 18–39.
750,000 veterans, 10.2-year follow-up. Extremely fit vs lowest fitness shows a 4-fold mortality difference. No increased mortality seen at highest fitness levels.
70,000+ participants. CRF and muscle strength together reduces mortality more than either alone. Strength training is a co-equal recommendation alongside aerobic activity.
CRF should be regarded as a clinical vital sign, as predictive of health outcomes as blood pressure or cholesterol. Routine CRF assessment is recommended.
234× more participants in MET-based CRF studies than VO₂Max studies. Over 99% of outcome data is based on METs. Wearable VO₂Max has 7–16% error and should not be used as a primary health metric.
Validates heart rate reserve (%HRR) + demographics for estimating MET intensity during free-living daily activity from wrist-worn wearables. Basis of Verve's Background Activity passive estimation.
Sedentary Behavior & Movement Balance
How Verve reads your day beyond workout minutes
Video walkthrough — Movement Balance
In production, coming soon
Sedentary Hours
Verve divides your day into one-hour slots from7am to 10pm. For each slot it reads your step count from Apple Health.
The 50-step threshold is intentionally low — even a short walk to the kitchen clears the hour. Apple Watch batches step data and syncs periodically, so today's count may dip and recover as earlier hours are updated.
Why hourly, not per-minute?Per-minute queries require HealthKit to process months of raw pedometer data at once — on most devices that query hangs indefinitely. Hourly data is pre-aggregated by iOS and returns instantly.
Standing Minutes · Apple Watch only
Apple Watch continuously monitors posture using its accelerometer and gyroscope. Verve reads Apple Stand Time — the raw cumulative minutes the Watch classified you as upright and moving.
This is not the green Stand ring. The ring counts hours where you stood for ≥1 minute (max 12/day). Standing Minutes counts the actual total — so 46 minutes across the day appears as 46, even if no single hour crossed the ring threshold.
Research shows total sedentary time and standing time are independent predictors of health outcomes — even for people who exercise regularly. Verve tracks both so you get the full picture beyond just workout minutes.
Meta-analysis of 47 studies, 240,818 person-years. Prolonged sedentary time is independently associated with all-cause mortality, cardiovascular disease, type 2 diabetes, and cancer — regardless of moderate-to-vigorous physical activity level. Participants in the highest quartile of sedentary time (≈10.6 h/day) had significantly elevated risk. Basis of Verve's first sedentary bar threshold at 10.6 h.
Pooled analysis of 16 studies, 1,005,791 individuals. Sitting ≥8 h/day was associated with increased all-cause mortality unless offset by 60–75 min/day of moderate physical activity — a threshold most adults do not reach. Risk was highest above 12 h/day of total sedentary time, regardless of activity. Basis of Verve's second sedentary bar threshold at 12 h.
Systematic review and meta-analysis of 13 prospective studies, 1,020,840 person-years. High sedentary time is associated with a 24% greater all-cause mortality risk, 14% greater CVD mortality risk, and 17% greater cancer risk, independent of physical activity. Risk increases steeply above 10 h/day.
7,985 adults followed for 4 years. Total sedentary time AND uninterrupted sitting bouts both independently predict mortality. Frequent breaks from sitting are protective even for those with the same total sedentary hours — supporting the importance of how sitting is distributed, not just how much.
Step Count & Daily Movement
Daily step tiers and cadence zones
Video walkthrough — Steps & Cadence
In production, coming soon
111,309 participants, 7.1-year follow-up. Dose-response relationship between daily step counts and all-cause mortality + cardiovascular events. Minimum effective dose: ~2,600 steps/day. CVD mortality benefit peaks around 7,200 steps/day. Basis of Verve's daily step tier thresholds.
Systematic review and dose-response meta-analysis. Optimal daily step count for all-cause mortality is approximately 8,800 steps/day. Confirms and extends the JACC 2023 findings across broader populations.
Prospective associations between daily step counts, cadence intensity, and cancer/cardiovascular disease incidence, CVD mortality, and all-cause mortality. Peak 30-minute cadence (steps/minute) independently predicts mortality regardless of total daily step volume.
Zone 2 Training
The weekly target, and the personal heart-rate band behind it
Video walkthrough — Zone 2 Training
In production, coming soon
ACC/AHA guidelines recommend at least 150 min/week of moderate-intensity (Zone 2) or 75 min/week of vigorous-intensity aerobic activity for primary prevention of cardiovascular disease. Strong evidence basis for Verve's 150–300 min/week Zone 2 target.
JACC Focus Seminar on exercise for primary and secondary CVD prevention. Confirms dose-response benefits of moderate-intensity exercise and supports Zone 2 as the primary training zone for cardiovascular health in the general population.
US Department of Health and Human Services evidence review underlying the 2018 Physical Activity Guidelines. Established 150–300 min/week of moderate-intensity activity as the target range with the greatest health benefit.
Heart-rate method: Karvonen HRR
"Zone 2" is a training label applied to the 40–60% Heart Rate Reserve band — different models (Seiler polarised, Maffetone 180-minus-age, San Millán VT1-based) draw the upper boundary slightly differently, but all target the same physiological space just below the first ventilatory threshold.
American College of Sports Medicine position stand on quantity and quality of exercise. Recommends 40–60% Heart Rate Reserve (HRR, Karvonen method) as the moderate-intensity aerobic training range. Basis of Verve's Karvonen HRR zone calculation.
AHA scientific statement on exercise standards for testing and training. Endorses the Karvonen (HRR) method for prescribing moderate-intensity exercise, anchoring intensity to resting HR for greater individualisation.
Heart Health
ApoB · LDL-C · Lp(a) · hs-CRP — screening bands, not treatment targets
Video walkthrough — Heart Health
In production, coming soon
For ApoB and LDL-C in particular, clinical targets are set by a person's overall cardiovascular risk category — a value in the "borderline" band may be perfectly appropriate for one person and a treatment trigger for another. Verve classifies against population screening bands and always defers to a clinician.
Risk-stratified ApoB goals: <65 mg/dL very-high risk, <80 mg/dL high risk, <100 mg/dL moderate risk. Verve screens against the <80 / <100 boundaries. ApoB counts atherogenic particles directly — one per LDL, IDL, VLDL and Lp(a) particle — capturing risk LDL-C alone can miss.
Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. Optimal <100, near-optimal 100–129, borderline-high 130–159, high 160–189, very high ≥190 mg/dL. Verve collapses the upper bands into one “elevated” tier for screening.
Risk rises continuously; commonly cited bands are <75 nmol/L (~<30 mg/dL) low, 75–125 nmol/L (30–50 mg/dL) intermediate, >125 nmol/L (>50 mg/dL) high. Lp(a) is ~90% genetically determined and stable through life — a single measurement is usually sufficient.
Relative cardiovascular risk bands: <1.0 mg/L low, 1.0–3.0 mg/L average, >3.0 mg/L high. Values above 10 mg/L usually reflect acute infection or inflammation rather than chronic cardiovascular risk — re-test once well.
Body Phenotyping
Metabolic syndrome screening, beyond BMI
Video walkthrough — Body Phenotyping
In production, coming soon
Joint Scientific Statement from IDF, NHLBI, AHA, WHF, IAS, and IASO. Defines metabolic syndrome as any 3 of 5 criteria: waist circumference, fasting glucose, blood pressure, triglycerides, and HDL. Verve flags ≥1 abnormal criterion — intentionally more sensitive than the clinical ≥3 threshold — to surface early metabolic risk before full syndrome develops.
Analysis of NHANES III data. Found that 31.7% of obese and 23.5% of overweight US adults are metabolically healthy — while 23.5% of normal-weight adults have ≥2 cardiometabolic risk abnormalities. Established that BMI alone is an unreliable proxy for metabolic health.
MRI and magnetic resonance spectroscopy study. Demonstrated that individuals with normal BMI can carry substantial visceral and liver fat — the TOFI (Thin Outside, Fat Inside) phenotype. Visceral fat, not subcutaneous fat, drives the elevated metabolic risk.
Muscle Health & Grip Strength
Why grip strength is in a fitness app at all
Video walkthrough — Muscle Health & Grip Strength
In production, coming soon
142,861 adults across 17 countries, median 4-year follow-up. For every 5 kg reduction in grip strength, cardiovascular death increased 17%, all-cause mortality 16%. Grip strength was a stronger predictor of cardiovascular death than systolic blood pressure. Low grip flags who lacks the physiological reserve to survive a cardiovascular crisis.
502,293 participants. Grip weakness (<26 kg men / <16 kg women) was associated with 26% higher all-cause mortality, 31% higher cardiovascular mortality — independent of physical activity, diet, and smoking. Obese individuals with high grip strength had lower mortality than non-obese individuals with low grip strength.