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In an investigation of the physical efficiency of schoolchildren, over a period of three years, we were impressed by (1) the high percentage of physically defective children; (2) the admission to school of physically subefficient children; (3) the inadequacy of the present system of physical examinations for the recognition and classification of abnormal conditions, and (4) the great need of objective methods for determining physical efficiency; the medical profession must admitthat a mere anatomic basis for classification of disease is inadequate for this purpose.Methods to determine physical efficiency are necessarily subjective, objective, or both. The subjective method concerns itself with an accurate history of the reaction of a person to his daily activities. Regarding objective methods, the literature in clinical medicine may be divided into two groups: (1) the quantitative measurement of capacity for physical work and (2) the reaction of the circulatory system to changes in posture and to measured amounts of work. This paper will limit itself to the discussion of the second group.For a better understanding of the physiologic principles upon which cardiovascular tests are based, the meaning of the terms "functional capacity" and "reserve of the heart" may be clarified by the following theoretical example.In a child, 11 years of age, weighing 35 kg., there are about 2.1 liters of blood. Forty-five seconds is required for a complete circulation of this amount of blood. With a systolic blood pressure of, let us say, 100 mm. (the pressure of a column of blood of 1.35 meters = il9°* 13" ), the work of the left ventricle in one minute would equal 1.35X2.1X4/3 = 3.78 kg.; in one day, therefore, 5,443 kg. It has been estimated that the right ventricle accomplishes about one third the amount of the work done by the left ventricle. Thus, at rest, the total output of the heart in twenty-four hours would be about 7,257 kg., as compared with about 14,000 kg. performed by the heart of the adult. Since, in violent exertion, the pulse rate can increase two times, and in times of emergency, the systolic blood pressure can rise
In an investigation of the physical efficiency of schoolchildren, over a period of three years, we were impressed by (1) the high percentage of physically defective children; (2) the admission to school of physically subefficient children; (3) the inadequacy of the present system of physical examinations for the recognition and classification of abnormal conditions, and (4) the great need of objective methods for determining physical efficiency; the medical profession must admitthat a mere anatomic basis for classification of disease is inadequate for this purpose.Methods to determine physical efficiency are necessarily subjective, objective, or both. The subjective method concerns itself with an accurate history of the reaction of a person to his daily activities. Regarding objective methods, the literature in clinical medicine may be divided into two groups: (1) the quantitative measurement of capacity for physical work and (2) the reaction of the circulatory system to changes in posture and to measured amounts of work. This paper will limit itself to the discussion of the second group.For a better understanding of the physiologic principles upon which cardiovascular tests are based, the meaning of the terms "functional capacity" and "reserve of the heart" may be clarified by the following theoretical example.In a child, 11 years of age, weighing 35 kg., there are about 2.1 liters of blood. Forty-five seconds is required for a complete circulation of this amount of blood. With a systolic blood pressure of, let us say, 100 mm. (the pressure of a column of blood of 1.35 meters = il9°* 13" ), the work of the left ventricle in one minute would equal 1.35X2.1X4/3 = 3.78 kg.; in one day, therefore, 5,443 kg. It has been estimated that the right ventricle accomplishes about one third the amount of the work done by the left ventricle. Thus, at rest, the total output of the heart in twenty-four hours would be about 7,257 kg., as compared with about 14,000 kg. performed by the heart of the adult. Since, in violent exertion, the pulse rate can increase two times, and in times of emergency, the systolic blood pressure can rise
In 1923, in a paper called "Physiology of Exercise," 1 we presented the results of a study of the physical capacity of children by means of a stationary bicycle. It was then pointed out that a considerable number of supposedly normal children fell below the average in physical strength and endurance. This striking observation led us to an inquiry into the psychophysiologic aspects of general subefficiency. The results were published in a paper called "Chronic Fatigue in the School Child: A
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