Indirect Calorimetry Research Paper

Essay 1: Indirect Calorimetry Indirect Calorimetry estimates the energy expenditure of the human body through measurements of expelled gases. Indirect calorimetry is not quite as accurate as direct calorimetry, which takes measurements of heat dissipated from the human body using heavy equipment, but it is less expensive to conduct experimentally, and provides one with the ability to measure oxygen consumption and carbon dioxide production. With these measurements, one gets a look into the overall aerobic physical fitness of the individual and their maximum oxygen uptake. Indirect calorimetry can also determine the primary source of energy being used using the Respiratory Exchange Ratio (RER). RER is non-invasive and provides information regarding the metabolic contribution of fat or carbohydrates. The idea is that one is constantly consuming and expelling air, so the difference between the oxygen inspired and expired over a given time frame would yield the total volume of oxygen consumed, VO2, because the expired air will contain less oxygen than the inspired air, the opposite being true with the air's carbon dioxide concentration. Most exercise physiology laboratories feel it is more cost-effective to only have one ventilation system, so while the oxygen

Insulin is stimulated by an increase in plasma glucose concentration. It's role pertains to decreasing those blood glucose levels by increasing the use of glucose as fuel or the storage of fat in adipose tissue. Whereas insulin targets most cells of the body, glucagon primarily targets the liver in particular. It comes into play when low glucose concentrations are detected by the sympathetic nervous system. Glucagon is responsible for the stimulation of glucose production from non-sugar substrates and the breakdown of glycogen into glucose so it can be further metabolized for energy production, or gluconeogenesis and glycogenolysis