Methodology & Sources

Vitalize translates published longevity research into an actionable daily protocol. Every score, projection, and habit recommendation in the app is derived from the peer-reviewed studies listed below. This page exists so anyone using Vitalize can verify exactly where our numbers come from. Vitalize is informational only and is not a substitute for professional medical advice.

Biological Age Engine

Vitalize computes a composite biological age from six physiological sub-systems: Cardiovascular, Metabolic, Sleep, Cognitive, Cellular, and Lifestyle. Our methodology draws from foundational research in biological age estimation and the pace of aging:

• Levine et al., Aging, 2018 — PhenoAge: composite biological age derived from clinical biomarkers
• Belsky et al., eLife, 2020 — Pace of Aging and the DunedinPACE epigenetic clock
• Horvath, Genome Biology, 2013 — Foundational work on epigenetic clocks and DNA methylation age

Sub-Age Scoring

Cardiovascular Age

Cardiovascular age is calculated from heart rate variability, resting heart rate, VO2 max estimates, and exercise capacity metrics.

• Shaffer & Ginsberg, Frontiers in Public Health, 2017 — HRV norms and age-related decline
• Mandsager et al., JAMA Network Open, 2018 — VO2 max and all-cause mortality
• Myers et al., New England Journal of Medicine, 2002 — Exercise capacity as a predictor of mortality

Metabolic Age

Metabolic age reflects energy expenditure patterns, dietary habits, and metabolic flexibility indicators.

• Barzilai et al., Diabetes, 2012 — Mechanisms of metabolic aging
• Salas-Salvadó et al., Annals of Internal Medicine, 2014 — Mediterranean diet and metabolic health
• Hall et al., Cell Metabolism, 2019 — Ultra-processed foods and metabolic dysregulation

Sleep Age

Sleep age incorporates sleep duration, consistency, deep sleep proportion, and sleep efficiency.

• Cappuccio et al., Sleep, 2010 — Sleep duration and mortality risk meta-analysis
• Windred et al., Sleep, 2024 — Sleep regularity and health outcomes
• Lucey et al., Science Translational Medicine, 2019 — Deep sleep and amyloid-beta clearance

Cognitive Age

Cognitive age is influenced by stress markers, mindfulness practices, and cognitive engagement patterns.

• Epel et al., PNAS, 2004 — Chronic psychological stress and telomere shortening
• Conklin et al., Psychoneuroendocrinology, 2018 — Mindfulness meditation and telomerase activity
• Hertzog et al., Psychological Science in the Public Interest, 2009 — Cognitive engagement and brain health

Cellular Age

Cellular age reflects mitochondrial function, inflammatory status, and recovery capacity.

• van der Lans et al., Journal of Clinical Investigation, 2013 — Cold exposure and mitochondrial biogenesis
• Calder, Biochemical Society Transactions, 2017 — Omega-3 fatty acids and systemic inflammation
• Plews et al., Sports Medicine, 2013 — HRV as a marker of training adaptation and recovery

Lifestyle Age

Lifestyle age accounts for behavioral factors including substance use, sun exposure, and social connectivity.

• Yang et al., Environmental Health Perspectives, 2019 — Smoking and accelerated epigenetic aging
• Lindqvist et al., Journal of Internal Medicine, 2014 — Sun exposure, vitamin D, and mortality
• Wood et al., The Lancet, 2018 — Alcohol consumption and health risk thresholds

Habit Impact Projections

Each habit recommendation in Vitalize includes a projected impact on biological age. These projections are calibrated against published effect sizes from interventional and observational studies:

• Sleep 7–9 hours: Cappuccio et al., Sleep, 2010
• 10,000 steps daily: Paluch et al., The Lancet Public Health, 2022
• Zone 2 cardio: San-Millán & Brooks, Sports Medicine, 2018
• Strength training: Liu et al., Medicine & Science in Sports & Exercise, 2019
• 16:8 intermittent fasting: Wilkinson et al., Cell Metabolism, 2020
• Cut ultra-processed food: Hall et al., Cell Metabolism, 2019
• Adequate hydration: Dmitrieva et al., eBioMedicine, 2023
• Meditation practice: Lazar et al., NeuroReport, 2005
• Social connection: Holt-Lunstad et al., Perspectives on Psychological Science, 2015
• Sauna use: Laukkanen et al., JAMA Internal Medicine, 2015
• Morning sunlight exposure: Wright et al., Current Biology, 2013

Habit Formation Threshold

Vitalize uses a 14–66 day window to track habit acquisition and automaticity. This range is based on research showing that habit formation varies by complexity and individual differences, with a median of 66 days for a behavior to become automatic.

• Lally et al., European Journal of Social Psychology, 2010 — Habit formation study establishing the 66-day median for automaticity

Limitations

The studies cited above report population-level effect sizes derived from cohort studies and clinical trials. Individual responses to lifestyle interventions vary based on genetics, baseline health status, adherence, and other factors. The projected year-deltas displayed in Vitalize are best-effort estimates based on aggregate evidence and should not be interpreted as guaranteed outcomes. Vitalize is not a diagnostic tool and does not replace laboratory biomarker testing, clinical evaluation, or professional medical guidance.