Final answer:
BMR and RMR are measurements of energy expenditure at rest, with BMR being measured under more strict conditions than RMR. Differences in these measurements are influenced by factors such as muscle mass and energy intake patterns. RMR is more commonly used due to its practical ease of measurement.
Step-by-step explanation:
The terms Basal Metabolic Rate (BMR) and Resting Metabolic Rate (RMR) both refer to the rate of energy expenditure by the body at rest, but they differ slightly in how they are measured. BMR is determined under more controlled conditions, including being in a post-absorptive state, which means it has been 10-12 hours after the last meal, and being in a physically and mentally relaxed state in a comfortable environment. On the other hand, RMR is typically easier to measure and may not require the stringent conditions that BMR does, making it more commonly used in casual settings. Both rates are affected by several factors such as age, gender, body weight, and muscle mass, with muscle mass burning more calories than body fat, therefore influencing the rate.
Furthermore, BMR is a function of maintaining basic bodily functions such as heart rate and respiration, which account for about 70 percent of daily energy expenditure, while physical activity accounts for about 20 percent, and the remaining 10 percent is for thermoregulation. Athletes often have higher BMR due to increased muscle mass. When it comes to weight management, it's important to note that the body can adjust BMR in response to prolonged changes in food intake, which is a significant factor for those attempting to lose weight through dieting and exercise.