Basal Metabolic Rate (BMR) is the amount of energy (measured in calories) that the body requires to sustain its most basic functions while at rest. These essential functions include breathing, circulation, cell production, and maintenance of body temperature. BMR accounts for the largest portion of total daily energy expenditure, representing the calories burned at rest, before factoring in physical activity or exercise.

Factors such as age, gender, body composition, and hormonal balance influence an individual's BMR.

Understanding your BMR is crucial for tailoring nutrition and exercise plans to achieve fitness goals, whether it's weight loss, maintenance, or muscle gain.