How does the level of muscular activity affect metabolic rate?

The level of muscular activity has a significant impact on metabolic rate. As a person becomes more active, their metabolic rate increases, resulting in higher heat production. For example, a person engaged in light physical activity such as walking may have a metabolic rate of 2-3 met, while someone engaged in strenuous activity such as running may have a metabolic rate of 8-10 met.