Your Resting Metabolic Rate
Your Resting Metabolic Rate (RMR) is the number of calories your body burns at rest to maintain basic life-sustaining functions like breathing, circulation, and cell production. This is a crucial metric for understanding your daily caloric needs, whether for weight management, athletic performance, or general health.
Understanding RMR
Your RMR is influenced by several factors, including your gender, weight, height, and age. Generally, men tend to have a higher RMR than women due to typically higher muscle mass. Muscle tissue burns more calories at rest than fat tissue. As you age, your RMR may naturally decrease.
How the Calculation Works
The most common and widely accepted formula for estimating RMR is the Mifflin-St Jeor equation. It's considered more accurate than older formulas like Harris-Benedict for most individuals. The formulas used here are:
- For Men: RMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
- For Women: RMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161
The result is an estimate in kilocalories (kcal) per day.
Factors Affecting RMR
While this calculator provides a good estimate, remember that your actual RMR can be influenced by other factors not included in the basic equation, such as:
- Body composition (muscle mass vs. fat mass)
- Hormone levels
- Genetics
- Certain medical conditions
- Medications
- Environmental temperature
For a precise measurement, consider undergoing a clinical RMR test (indirect calorimetry).
Example Calculation
Let's calculate the RMR for a 35-year-old male who weighs 80 kg and is 180 cm tall:
Using the Mifflin-St Jeor equation for men:
RMR = (10 × 80) + (6.25 × 180) – (5 × 35) + 5
RMR = 800 + 1125 – 175 + 5
RMR = 1755 kcal/day
So, this individual burns approximately 1755 calories per day at rest.