Which factor does NOT affect Basal Metabolic Rate?

Basal Metabolic Rate (BMR) refers to the number of calories your body needs to maintain basic physiological functions while at rest, such as breathing, circulation, and cell production. BMR is influenced by various factors, including genetics, age, gender, body composition, and certain external conditions such as stress and temperature.

Routine exercise, while important for overall health and can increase caloric expenditure during activity, does not have a direct effect on BMR itself. Instead, it primarily affects how many calories are burned during activity, not the number of calories required at rest. In contrast, factors like stress can elevate metabolic rates temporarily due to hormonal changes, while fasting can lower the metabolic rate as the body conserves energy. Environmental temperature can impact BMR as well, as the body expends energy to maintain a stable internal temperature.

Through understanding the distinctions among these factors, it becomes clear that routine exercise is not a direct determinant of BMR, making it the correct choice for this question.