Basal metabolic rate be elevated in stress, illness, and diabetes. Menopause may also affect metabolism. Heart rate is determined by the medulla oblongata and part of the pons, two organs located inferior to the hypothalamus on the brain stem. Heart rate is important for basal metabolic rate and resting metabolic rate because it drives the blood supply, stimulating the Krebs cycle. During exercise that achieves the anaerobic threshold, it is possible to deliver substrates that are desired for optimal energy utilization. The anaerobic threshold is defined as the energy utilization level of heart rate exertion that occurs without oxygen during a standardized test
Electrical conduction system of the heart If SA nodal impulses occur at a rate less than 60bpm, the heart rhythm is known as sinus bradycardia. If SA nodal impulses occur at a rate exceeding 100bpm, the consequent rapid heart rate is sinus tachycardia. These conditions are not necessarily bad symptoms, however. Trained athletes, for example, usually show heart rates slower than 60bpm when not exercising. If the SA node fails to initialize, the AV junction can take over as the main pacemaker of the heart. The AV junction consists of the AV node, the bundle of His, and the surrounding area; it has a regular rate