The Science Behind BioAge

Your Biological Age is a transparent, formula-based estimate derived from lifestyle data. No machine learning — every coefficient is visible and explainable.

The Core Formula

delta_years = (Lifestyle Index - 70) × -0.18, capped at ±12 years

If your Lifestyle Index is 70 (average), your BioAge equals your chronological age. An index of 100 gives you roughly 5.4 fewer years; an index of 40 adds about 5.4 years.

Lifestyle Index Weights

Sleep (duration + quality)25%

Activity (steps, active minutes, resting HR)25%

Nutrition quality20%

Body composition (BMI + waist-to-height)15%

Smoking & alcohol15%

How Each Component is Scored (0-100)

Sleep

Duration (7-9h = 100) weighted 60% + quality rating (1-5) weighted 40%.

Activity

Steps (10k = 100) 40% + active minutes (30+ = 100) 40% + resting HR (60-70 = 100) 20%.

Nutrition

Average of fiber (25g+ = 100), added sugar (0g = 100), fruit/veg servings (5+ = 100), protein (60g+ = 100).

Body

BMI (18.5-24.9 = 100) + waist-to-height ratio (<0.5 = 100) if provided.

Smoking & Alcohol

Non-smoker = 100, smoker loses 70 points. Alcohol >7 drinks/week scales down.

Confidence

Confidence is based on data completeness: 7+ days of logs = 100% confidence. A minimum of 3 days is required before a score is shown.

Improvement Levers

Each lever shows the estimated years of improvement if you optimized that component to 100. The calculation: (100 - current score) × weight × 0.18. Estimates assume 8-16 weeks of sustained change.

Educational estimate only. Not a medical assessment or diagnosis. Consult a healthcare professional.