"Hypermetabolic" is the adjectival form of "hypermetabolism," which is an increase in the body's basal metabolic rate. Hypermetabolism can be a symptom of underlying stress or significant physical trauma.
Hypermetabolism can cause sudden weight loss, fatigue, an elevated or otherwise irregular heart rate, muscle weakness, and shortness of breath. If caused by a trauma to the body, such as an infection, burn or fracture, then the symptoms of hypermetabolism usually subside once the underlying cause is treated. A hypermetabolic state in the body also causes a significant increase in the nutritional needs of the patient and can therefore become even more taxing to the body.