The rate at which energy (calories) is used for the essential life functions is called Basal Metabolic Rate (BMR). Basal metabolism includes most of the involuntary things the human body does to support life – such as breathing, blood circulation, body temperature regulation, nervous system operations, etc., but not the extra energy needed for any additional physical activity such as gym exercise.

In other words, if you laid in bed all day doing nothing else, then you would need to eat at least the number of calories roughly equal to your BMR in order to maintain your normal body functions.

Basal metabolism consumes from 60 to 70% of body’s total daily calories expenditure.

Resting Metabolic Rate (RMR) is equivalent to BMR but is measured under less strict conditions. BMR usually assumes special lab conditions where even the room temperature has to be exact. RMR is the BMR value adjusted for the regular life environment.

RMR values are about 15% higher than the BMR values.

In your diet calculations, you can safely use RMR instead of the scientifically precise BMR.