It has numerous causes, both physiological (part of the body's normal function) and pathological (associated with disease).
[1] Tall, thin people have a higher BMR than their shorter counterparts, even with the same weight, due to the greater surface area of their skin.
[3] A common pathological cause for a high BMR is fever, since a rise in body temperature increases the rate of cellular metabolic reactions.
[1] It is estimated that for every degree Fahrenheit of rise in body temperature, the BMR increases by 7 percent.
[1] Prolonged periods of abnormal nutrition cause an adaptive change in BMR; this helps the body to maintain a stable body weight in response to the change in food supply.