. Stress test. Man undergoing a stress test, which usually involves strenuous exercise while physiological body measurements are taken. Here, lung function is being monitored by a peak flow meter into which the patient breathes. Sensors attached to his chest monitor heart rate. Under physical or emotional strain, hormones secreted by the body lead to changes in heart rate, depth of breathing, and normal metabolism. Above certain levels of stress an individual's ability to cope may be impaired. In this stress test, physiological measurements give a measure of how fit the body is and assesses its ability to deal with physical strain. MODEL RELEASED

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