About

Metabolic Age is a comparative metric that relates your Basal Metabolic Rate (BMR) to the average BMR of your chronological age group. If your BMR is higher than the average for your age (often due to higher muscle mass), your metabolic age will appear younger, indicating better metabolic health. Conversely, a lower BMR can suggest muscle atrophy or metabolic adaptation.

This tool uses the clinically validated Mifflin-St Jeor equation, considered the gold standard for accuracy in non-obese individuals. It provides a "Vitality Score" and calculates the Total Daily Energy Expenditure (TDEE) needed to maintain current physiological function, offering actionable insights on how body composition changes can "reverse" aging.

Formulas

Mifflin-St Jeor Equation (Metric):

BMR = 10W + 6.25H − 5A + S

Where W is weight (kg), H is height (cm), A is age (years), and S is the gender constant (+5 for men, −161 for women).

Metabolic Age Logic (Simplified):

Age_metabolic = Age_chrono + BMR_avg − BMR_userk

Reference Data

Activity Level	Multiplier (PAL)	Description
Sedentary	1.2	Office job, little to no exercise.
Lightly Active	1.375	Light exercise 1-3 days/week.
Moderately Active	1.55	Moderate exercise 3-5 days/week.
Very Active	1.725	Hard exercise 6-7 days/week.
Extra Active	1.9	Physical job or 2x training/day.

Frequently Asked Questions

This usually indicates your BMR is lower than the average for your age group. The most common cause is low muscle mass relative to body fat. Strength training to build muscle is the most effective way to lower metabolic age.

No. BMR (Basal Metabolic Rate) is the energy your body burns just to stay alive (breathing, circulation) at complete rest. Your TDEE (Total Daily Energy Expenditure) adds activity calories on top of BMR.

It is widely cited as the most reliable predictive equation, usually within 10% of true metabolic rate measured by calorimetry. However, it does not account for lean body mass directly; extremely muscular individuals may be underestimated.