MODEL RELEASED. Fitness test. Doctor assessing the fitness of a male athlete running on a treadmill. The athlete is wearing a mask that measures his oxygen consumption and carbon dioxide production during breathing. The data is shown on the computer monitor at far left. Each peak on the graph represents one breath. The resulting data, in combination with other physiological measurements such as heart rate and blood pressure, can be used to determine the ability of the body to cope with exertion, and to develop personal fitness regimes for athletes. Photographed at the Centro Sportivo, Rome, Italy.