BMR
Basal Metabolic Rate (BMR) is the amount of energy your body needs at rest to maintain basic physiological functions - breathing, circulation, cell production, and temperature regulation. It represents roughly 60-70% of total daily energy expenditure.
Common formulas:
-
Mifflin-St Jeor (most accurate for most people):
- Men: BMR = (10 × weight kg) + (6.25 × height cm) - (5 × age) + 5
- Women: BMR = (10 × weight kg) + (6.25 × height cm) - (5 × age) - 161
-
Harris-Benedict (older, slightly less accurate):
- Men: BMR = 88.36 + (13.4 × kg) + (4.8 × cm) - (5.7 × age)
- Women: BMR = 447.6 + (9.25 × kg) + (3.1 × cm) - (4.3 × age)
Factors that affect BMR:
- Body composition (more muscle = higher BMR)
- Age (decreases ~2% per decade after 20)
- Sex (men typically 5-10% higher)
- Thyroid hormones (major regulator)
- Body surface area
- Fever, illness, pregnancy
Clinical uses: BMR is used to calculate Total Daily Energy Expenditure (TDEE) by multiplying by an activity factor (1.2 sedentary to 1.9 very active), which guides caloric needs for weight management, clinical nutrition, and critical care feeding.
Would you like me to calculate your BMR, explain the physiology in more depth, or cover something specific like BMR in disease states?
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