Calories & Nutrition
What Is BMR? Basal Metabolic Rate Explained
BMR is the calories your body burns at complete rest. Here's how it's measured and why it matters.
6 min read·Updated 25 June 2026
HG
HealthGood Editorial Team
Last updated 25 June 2026
Reviewed by HealthGood Editorial Standards Board
Basal Metabolic Rate (BMR) is the energy your body needs to keep its essential systems running — heart, lungs, brain, organs — at complete rest.
What affects BMR
- Body size — bigger bodies generally burn more.
- Lean mass — muscle is more metabolically active than fat.
- Age — BMR tends to decline gradually after about age 30.
- Sex — men typically have higher BMR due to greater lean mass.
- Genetics, hormones, and climate.
How BMR is calculated
The Mifflin-St Jeor equation is the modern standard for estimating BMR without lab equipment. True BMR is measured by indirect calorimetry in a controlled clinical setting.
Frequently asked questions
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References
- World Health Organization — Body mass index (BMI). https://www.who.int
- NHS — Healthy weight and BMI. https://www.nhs.uk
- Centers for Disease Control and Prevention (CDC) — Healthy Weight, Nutrition, and Physical Activity. https://www.cdc.gov
- Mifflin MD, St Jeor ST, et al. A new predictive equation for resting energy expenditure. Am J Clin Nutr (1990).