The sum of all the chemical processes in the body involved in creating and using energy to carry out vital functions such as digestion, growth, breathing, temperature regulation, and elimination of bodily wastes.
Basal metabolic rate (BMR), which is defined as the number of calories the body uses at rest to carry out life-sustaining processes, accounts for anywhere between 50% and 75% of daily caloric expenditure. It is influenced by a number of factors, including age, sex, muscle mass, and hormone levels. Thyroid hormones play a particularly important role in determining BMR by regulating oxygen consumption and heat production in most areas of the body.
Total metabolic rate (TMR), the rate at which calories are used to fuel all ongoing activities, is also influenced by a number of variables, but physical activity is the main one. Exercise raises the rate at which calories are burned both during the activity and for several hours afterward. When performed regularly, physical activity can even result in an increased BMR.
Obesity and Type 2 diabetes are both considered metabolic disorders. Obesity, which is a risk factor for Type 2 diabetes, is generally defined as being 20% or more over one’s ideal body weight or having a body-mass index of 30 or higher. It involves having an abnormally high proportion of body fat. Obesity results from an imbalance between energy intake and energy expenditure. In Type 2 diabetes, disturbances in insulin function interfere with the metabolism of carbohydrate, affecting the way the body derives energy from food.
Obesity and Type 2 diabetes can often be prevented by decreasing energy consumption (eating less) and increasing energy expenditure (exercising more). Regular aerobic exercise not only uses energy but also helps the heart work more efficiently. Strength training can increase muscle mass and, therefore, metabolic rate. If you have yet to begin an exercise program, ask your health-care provider about the best way to get started.