Resting Metabolic Rate (RMR) accounts for 60–75% of daily calorie expenditure. It's slightly higher than BMR because it includes the energy cost of minimal daily activity (sitting, digesting food).
RMR vs. BMR
BMR is measured under strict lab conditions (12-hour fast, complete rest). RMR is measured under less restrictive conditions and is typically 10–20% higher than BMR. For practical purposes, they're often used interchangeably.
Factors That Increase RMR
- More muscle mass (muscle burns ~6 cal/lb/day vs fat at ~2 cal/lb/day)
- Younger age
- Male sex (higher lean mass on average)
- Thyroid function