Final answer:
The slope of the regression line between lean body mass and the resting metabolic rate indicates how much the metabolic rate increases with each additional kilogram of lean body mass. Lean tissue burns more calories than fat, which means that as lean muscle mass increases, so does the amount of calories burnt at rest.
Step-by-step explanation:
Exercise physiologists are interested in the relationship between lean body mass and resting metabolic rate (RMR). Based on the way these two variables interact, the slope of the regression line represents the change in the resting metabolic rate for each additional kilogram of lean body mass. The slope indicates how much the RMR increases for each unit increase in lean body mass. It is known that lean tissue is more metabolically demanding than fat tissue, meaning it burns more calories. Also, a person's BMR generally decreases with aging as lean muscle mass tends to decrease, and since men typically have more lean muscle mass than women, their BMR is usually higher.
For instance, vigorous physical exercise not only helps burn calories but also raises the BMR by building extra lean tissue. In terms of measuring metabolic rates, a 'Calorie' with a capital 'C' is used to describe the energy consumed and is equivalent to 1000 calories, which is the energy needed to heat 1 kg of water by 1 °C. Understanding these relationships allows for the development of better recommendations and regimens for nutrition and exercise, which can be adapted to enhance both lean body mass and metabolic rate, thereby positively influencing health and weight management.