Basal Metabolic Rate is the minimal caloric requirement needed to sustain life in a resting individual. Let's look at some factors that affect BMR:Age: In youth, the BMR is higher; age brings less lean mass and slows the BMR. Height: Tall, thin people have higher BMR's. Growth: Children and pregnant women have higher BMR's. Body Composition: The more lean tissue, the higher the BMR.The more fat tissue, the lower the BMR.