Fitness · topic 2 of 5
Cardiorespiratory fitness
The five tiers, and why they are read against your own age and sex
Men, 40 to 49
Figures in METs, for one reader. Your own table depends on your age and sex, and on which dataset covers you.
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.
Kodama et al, JAMA 2009
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 events. A maximal capacity of 7.9 METs or more carried substantially lower risk. That 7.9 is a fitness level, not a weekly volume; Verve's weekly milestones come from the WHO 2020 guidelines instead. (This card was attributed to Blair et al until September 2026; PMID 19454641 is Kodama.)
PMID 19454641 →
Mandsager et al, Cleveland Clinic 2018
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.
PMID 30646252 →
Kokkinos et al 2022
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.
PMID 35926933 →
Kim et al, UK Biobank
70,000+ participants. CRF and muscle strength together reduces mortality more than either alone. Strength training is a co-equal recommendation alongside aerobic activity.
PMID 29594847 →
AHA 2016 Scientific Statement
CRF should be regarded as a clinical vital sign, as predictive of health outcomes as blood pressure or cholesterol. Routine CRF assessment is recommended.
PMID 27881567 →
Why not VO₂Max? (Topol commentary)
Commentary234× 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.
erictopol.substack.com →
Nakanishi et al 2021
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.
pubmed.ncbi.nlm.nih.gov →