BMR (Basal Metabolic Rate)

What is BMR (Basal Metabolic Rate)?

Calories your body needs at complete rest to maintain vital functions like breathing and circulation.

Why it matters

BMR is the foundation of TDEE and shapes calorie planning.

How it works

Commonly estimated using Mifflin–St Jeor based on age, sex, weight, and height.

Two people with different weights and ages will have different BMRs even with the same height.
A 30-year-old man, 180 cm, 80 kg, has BMR ~1,800 kcal; a 50-year-old woman, same height/weight, ~1,600 kcal.
Athletes with high muscle mass have higher BMR than sedentary individuals of similar size.
During weight loss, BMR decreases slightly as body weight drops.
Pregnancy increases BMR due to fetal development and maternal changes.

Does more muscle raise BMR?

Yes, generally muscle increases resting energy use.

How to measure BMR accurately?

Use indirect calorimetry in a lab; at home, use equations or wearables.

What factors affect BMR?

Age, sex, weight, height, muscle mass, hormones, and genetics.

Does age lower BMR?

Yes, BMR decreases by about 2% per decade after age 20.

Can diet change BMR?

Extreme calorie restriction can lower BMR; adequate protein helps maintain it.

Is BMR the same as RMR?

Similar; RMR is measured in less strict conditions.

How does thyroid function affect BMR?

Hypothyroidism lowers BMR; hyperthyroidism raises it.

Can exercise increase BMR?

Building muscle increases BMR; cardio has minimal long-term effect.

What's a normal BMR range?

Varies widely; 1,200-2,500 kcal for adults depending on size.

Does caffeine affect BMR?

Slightly increases it temporarily.

How to boost BMR naturally?

Build muscle, stay hydrated, eat protein-rich meals.

Is BMR higher in men?

Yes, due to more muscle mass.

Can stress affect BMR?

Chronic stress may slightly increase it via cortisol.

What's the difference between BMR and metabolism?

BMR is part of metabolism; metabolism includes all energy use.