BASAL METABOLIC RATE
Your basal metabolic rate (BMR) is the energy used (measured in calories) by your body to perform basic functions, including internal energy expenditure, breathing and body temperature. It is the number of calories your body would expend if you performed no physical activity throughout the day.
Adding even small amounts of lean muscle with proper nutrition and exercise can increase your BMR and allow you to burn more calories on a daily basis. This is another example of how an active lifestyle and healthy eating can help improve your ability to burn calories outside of the gym.