What term refers to the amount of energy required to maintain all internal activities while at rest?

The term that describes the amount of energy needed to maintain all internal activities while at rest is basal metabolic rate (BMR). BMR specifically refers to the minimum amount of energy required for basic physiological functions such as breathing, circulation, cell production, and nutrient processing when the body is in a state of complete rest. This measurement is typically taken under standardized conditions—after a full night’s sleep and in a fasting state.

Caloric expenditure refers more broadly to the total number of calories burned through all daily activities, including exercise and movement, not just the energy needs at rest. Resting energy expenditure (REE) is similar to BMR but may include a slight increase in energy expenditure due to the digestion of food or other minor activities. However, REE can fluctuate based on recent physical activity or food intake. Active metabolic rate emphasizes the energy used during physical activities and exercise, which is much higher than the energy needed while at rest.

Understanding this distinction is crucial for personal training and nutrition planning, as it helps in determining an individual's daily caloric needs for maintaining or changing body weight.