Pace of Aging Index: Open Lifestyle-Trajectory Score
A transparent 0 to 100 lifestyle-trajectory score from habits and simple measures: you versus your own potential, not a biological age.
- 2 cited sources
- Calculates in your browser
Your answer
Appears here as you enter your details. No demo figures — the number is yours, or it is nothing.
Baseline
Know all your numbers
BMI, resting rate, daily burn, eating target, macros, body fat, waist ratios, heart-rate zones and your fitness age: 15 in all. Answer once, see them together, and stop whenever you like.
Get my Baseline →Methodology
The Pace of Aging Index is an open composite index (v1.0.0), a transparent 0 to 100 score summarising how favourable your current lifestyle trajectory looks. It is explicitly not a biological age; it's built from modifiable habits and simple measures, framed as levers you can move.
Each input becomes a 0 to 100 sub-score (higher = more favourable) via a documented clamped-linear mapping, then combined by weight:
| Input | Weight | Tier |
|---|---|---|
| Cardio fitness (VO₂max), optional | 25% | T1 |
| Waist-to-height | 12% | T1 |
| Grip strength, optional | 12% | T1 |
| Activity volume (MVPA) | 12% | T1 |
| Sleep | 12% | T2 |
| Resting heart rate | 10% | T2 |
| HRV, optional | 10% | T2 |
| Smoking | 5% | T1 |
| Alcohol | 2% | T2 |
Cardiorespiratory fitness carries the most weight in the design, but our dedicated fitness-age estimate is on hold pending a source we can verify, so VO₂max is optional here (enter a known value, or skip it). Grip and HRV are optional too. Leave any optional input blank and the weights renormalise across what you provided, with a reduced-confidence flag. Full house methodology is on the index methodology page.
The pace number is a centred display of the same index (~0.8 favourable to ~1.2 less favourable), a display transform, not a hidden model.
Interpreting your result
Look at the radar and sub-scores, not just the headline. They show which habits are lifting or dragging your trajectory, and every one of them is modifiable. A low sub-score is a next step, never a verdict. Body-composition (waist-to-height) is deliberately capped at 12% so the score can never be dominated by, or reward chasing, a single body measurement.
Track your own trend. Because the weights and mappings are fixed and versioned, a change in your score reflects a real change in your habits.
Limitations
- This is a self-tracking construct, not a biological age and not a medical test; it hasn't been validated against health outcomes.
- The sub-score anchors are reasonable but chosen by us and published so you can judge them; different anchors would give different numbers.
- Cardio fitness, the input with the strongest evidence, is optional pending a verifiable source, which lowers confidence when it's omitted.
- It describes lifestyle, not destiny: genetics and circumstance matter enormously and aren't captured here.
Sources
Pull the receipts, 2 cited sources
FitTools · sources
- 01 WHO Guidelines on physical activity and sedentary behaviour, 2020 (150 to 300 min/week MVPA)
- 02 Ashwell M, Gibson S. Waist-to-height ratio and early health risk (0.5 boundary)
Every formula cited ✓
Frequently asked questions
- Is this my biological age?
- No, deliberately not. It's a transparent lifestyle-trajectory score built from modifiable habits and simple measures. It shows how your current lifestyle stacks up, framed as levers you can change, not a claim about your cells' age.
- What is the 'pace' number?
- A centred display of the same 0 to 100 index, roughly 0.8 (favourable) to 1.2 (less favourable). It's just another way to read the score, where lower suggests a lifestyle trajectory tracking younger. It's a display transform, not a separate hidden model.
- Do I need a VO2max, grip or HRV number?
- No. Those three inputs are optional, so enter them only if you know them from a test or wearable. Leave them blank and the score renormalises across what you did provide, flagging reduced confidence. It never guesses a value.
- Why is cardio fitness optional here?
- Cardiorespiratory fitness carries real weight in the methodology, but our dedicated fitness-age tool is on hold pending a source we can verify. Rather than estimate it unreliably, we let you enter a known VO2max or skip it.
- Is this a medical test?
- No. It's a transparent self-tracking index, not validated against health outcomes and not a diagnosis. Everything is computed in your browser.
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