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The Health NestEgg Calculator
Interactive · Two-Mechanism Model
Deposit Level
Health Balance
52 weeks
0 wk104 wk208 wk
Challenges (past 12mo)
0
024
Formula
Health NestEgg = 1 − (1 − Dose) × (1 − Fitness)
Dose = target × maturity
Maturity = 1 − e−weeks/52
Fitness Bonus = +3% per Challenge
20%
Health NestEgg
Exercise Dose 20%
Fitness Bonus 0%
Total Protection 20%
Maturity: 63%
Reference Scenarios (ACM)
ScenarioDoseFit.Total
L1+Str · 52wk · 0Ch26%0%26%
L1+Str · 52wk · 4Ch26%12%35%
L1+Str · 104wk · 4Ch35%12%43%
L4+Str · 208wk · 4Ch45%12%52%
Protection by Condition
Exercise Dose Fitness Bonus

How to Use the Health NestEgg Calculator

The Health NestEgg Calculator shows you a simple thing: how much estimated protection against chronic disease and premature death you build up from the exercise habit you maintain through NestEgg. It’s a visualization of your Health NestEgg — the protective effect of a sustained, dose-measured activity habit across nine conditions including cardiovascular disease, type 2 diabetes, dementia, depression, and several cancers.

Think of it as a financial planner for your health. You make weekly deposits. Over time, the NestEgg grows.

The three inputs

Input What it means
Deposit Level The weekly dose you’re holding. Choose from Inactive, L1 Aerobic (WHO minimum, ~150 EP/week), L1 + Strength, L4 Aerobic (WHO ideal dose), or L4 + Strength.
Health Balance How many consecutive weeks you’ve been hitting that Deposit Level. Drag 0 → 208 weeks (four years). Protection matures exponentially: ~63% of the full benefit after 52 weeks, ~93% after 140 weeks.
Challenges (past 12 months) How many NestEgg Challenges you’ve completed in the last year. Each one adds a small cardiorespiratory-fitness bonus.

What the dial tells you

Output Meaning
Exercise Dose Protection Risk reduction earned by your sustained weekly dose × how mature that habit is.
Fitness Bonus Protection The extra reduction from fitness gains earned during Challenges.
Total Health NestEgg The two combined: 1 − (1 − Dose) × (1 − Fitness). This is the number in the ring.

How to read the result

Drag the sliders and watch the ring fill. A couple of useful reference points:

Reference Data

The numbers come from peer-reviewed meta-analyses of observational cohort studies (Arem et al. 2015, Momma et al. 2022, Saeidifard et al. 2019, and others). They describe population-level associations, not causal guarantees for any one person. Read the result as a directionally accurate projection of what a sustained habit tends to deliver — not a medical prediction.

Move the sliders. See what four years of small, steady deposits is worth.

Sources & References
All claims in this model are derived from peer-reviewed meta-analyses and longitudinal cohort studies.
Exercise Dose (Mechanism 1)
  1. Arem H, et al. (2015). "Leisure time physical activity and mortality." JAMA Internal Medicine. 661,137 adults, 14.2-year median follow-up.
  2. Momma H, et al. (2022). "Muscle-strengthening activities and mortality." British Journal of Sports Medicine. Meta-analysis of 16 studies.
  3. Saeidifard F, et al. (2019). "The association of resistance training with mortality." Preventive Medicine. 370,256 participants.
  4. Zhao M, et al. (2020). "Recommended physical activity and all-cause and cause-specific mortality." European Journal of Epidemiology. Meta-analysis.
  5. Pearce M, et al. (2022). "Association between physical activity and risk of depression." JAMA Psychiatry. 15 prospective studies.
  6. Hamer M & Chida Y. (2009). "Physical activity and risk of neurodegenerative disease." Psychological Medicine. Meta-analysis.
  7. Kyu HH, et al. (2016). "Physical activity and risk of breast cancer, colon cancer, diabetes, ischaemic heart disease, and stroke." The BMJ. 174 studies.
  8. Pandey A, et al. (2021). "Dose-response relationship between physical activity and risk of heart failure." Circulation. Meta-analysis.
  9. Lee CD, et al. (2003). "Physical activity and stroke risk." Stroke. Meta-analysis.
  10. Ding D, et al. (2016). "The economic burden of physical inactivity." The Lancet. $67.5 billion global cost.
  11. Carlson SA, et al. (2015). "Inadequate physical activity and health care expenditures." Preventing Chronic Disease.
  12. Chakravarty EF, et al. (2008). "Reduced disability and mortality among aging runners." Archives of Internal Medicine. Stanford Runners Study, 21-year follow-up.
  13. RAND Corporation. (2013). "Workplace wellness programs study." Published by RAND Health.
  14. Lee DH, et al. (2022). "Long-term physical activity intensity and mortality." Circulation. 116,221 adults, 30-year follow-up.
  15. Ekelund U, et al. (2016). "Does physical activity attenuate, or even eliminate, the detrimental association of sitting time with mortality?" The Lancet. 1,005,791 individuals.
  16. Shailendra P, et al. (2022). "Resistance training and mortality risk." American Journal of Preventive Medicine.
  17. Moore SC, et al. (2016). "Physical activity and cancer risk." JAMA Internal Medicine. 1.44M adults.
  18. Moore SC, et al. (2012). "Physical activity and life-years gained." PLOS Medicine. 654,827 individuals.
  19. Smith AD, et al. (2016). "Physical activity and type 2 diabetes." Diabetologia.
  20. Iso-Markku P, et al. (2022). "Physical activity and dementia." British Journal of Sports Medicine.
  21. Li Y, et al. (2020). "Healthy lifestyle and disease-free life expectancy." BMJ. 111,562 adults.
  22. Lally P, et al. (2010). "How are habits formed?" European Journal of Social Psychology.
  23. Wahid A, et al. (2016). "Physical activity, CVD and diabetes." Journal of the American Heart Association.
  24. Blond K, et al. (2020). "High amounts of physical activity and mortality." British Journal of Sports Medicine.
Cardiorespiratory Fitness / CRF (Mechanism 2)
  1. Singh B, et al. (2024). "Cardiorespiratory fitness is a strong and consistent predictor of morbidity and mortality." British Journal of Sports Medicine. Overview of 26 systematic reviews, 20.9M observations, 199 unique cohort studies.
  2. Kodama S, et al. (2009). "Cardiorespiratory fitness as a quantitative predictor of all-cause mortality and cardiovascular events." JAMA. 33 studies, 102,980 participants.
  3. Mandsager K, et al. (2018). "Association of cardiorespiratory fitness with long-term mortality among adults undergoing exercise treadmill testing." JAMA Network Open. 122,007 patients.
  4. Sørensen TIA, et al. (2018). "Midlife cardiorespiratory fitness and the long-term risk of mortality: 46 years of follow-up." Journal of the American College of Cardiology. 5,107 men, Copenhagen Male Study.
  5. Poon ETC, et al. (2024). "High-intensity interval training and cardiorespiratory fitness in adults." Scandinavian Journal of Medicine & Science in Sports. Umbrella review of meta-analyses.
  6. Kokkinos P, et al. (2022). "Cardiorespiratory fitness and mortality risk across the spectrum of age, sex, and fitness." Journal of the American College of Cardiology. 750,000+ US veterans.
  7. Milanović Z, et al. (2015). "Effectiveness of high-intensity interval training (HIIT) and continuous endurance training for VO₂max improvements." Sports Medicine. 45(10), 1469–1481.
Detraining & Fitness Preservation
  1. Mujika I & Padilla S. (2000). "Detraining: Loss of training-induced physiological and performance adaptations. Part I." Sports Medicine. 30(2), 79–87.
  2. Mujika I & Padilla S. (2001). "Cardiorespiratory and metabolic characteristics of detraining in humans." Medicine & Science in Sports & Exercise. 33(3), 413–421.
Maturity Model (4-Year Timeline)
  1. Howden EJ, et al. (2015). "Reversing the cardiac effects of sedentary aging in middle age." Journal of the American College of Cardiology.
  2. Knowler WC, et al. (2002). "Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin." New England Journal of Medicine. 346(6), 393–403. n = 3,234.
  3. Henke RM, et al. (2011). "Recent experience in health promotion at Johnson & Johnson: lower health spending, strong return on investment." Health Affairs. 30(3), 490–499.
Healthcare Cost & ROI Evidence
  1. Matjasko JL, et al. (2025). "Healthcare expenditures associated with meeting vs. not meeting physical activity guidelines." American Journal of Health Promotion. CDC-coauthored. $192 billion annual US cost of inactivity.
  2. Discovery Vitality. "Shared-value insurance model outcomes." 50M+ life-years of data across 40+ markets.
  3. Baicker K, et al. (2010). "Workplace wellness programs can generate savings." Health Affairs. 29(2), 304–311. 3.27:1 ROI.
  4. Song Z & Baicker K. (2019). "Effect of a workplace wellness program on employee health and economic outcomes." JAMA. 321(15), 1491–1501. Large RCT (n=32,974).
  5. Jones D, et al. (2019). "What do workplace wellness programs do? Evidence from the Illinois Workplace Wellness Study." Quarterly Journal of Economics. 134(4), 1747–1791.