Work speed as a measure of an equivalent exercise stress in subjects of different weights.

THE PULSE RATE during and after exercise has been utilized in a number of ways to assess unfitness.1 16 The simplest method has been to measure the pulse rate at specified times after effort and to record the time taken for the pulse rate to return to the resting level. Alternatively, the pulse rate has been measured during exercise. In both instances, unfitness has been judged by the degree to which the pulse rate exceeds normal limits for a specific work load. One test procedure has been devised to assess unfitness from the work load which is required to produce a specific pulse rate.2 Possibly the most sophisticated tests of fitness allow an estimate of the maximum work load capacity or maximum oxygen uptake capacity.-5, 10, 11 The present study indicates that the weight of the subject has a definite influence on the pulse rate when subjects of different weights perform a constant work load. The heart rate, however, is a linear function of work speed and is shown to be independent of the body weight. Material and Methods Eighty-one normal adult men between the ages of 16 and 47 years (mean age 26 years) were studied. Subjects were chosen randomly from the first available applicants at the Miners' Medical Bureau, Johannesburg (altitude 5,760 ft.). Criteria for acceptance included a normal clinical examination and radiogram of the chest. No consideration was given to previous physical training except that the subjects were ambulatory and had 940 not suffered any illness demanding bed rest in the previous month. Each subject was weighed without shoes or a shirt prior to the commencement of the test. At least 2 hours had elapsed since the last meal. The resting pulse rate was noted after 15 minutes of rest. The subjects were required to perform a step test at 200, 300, 400, and 500 Kg. M./min. work, which was continued for 15 minutes. The step test consisted of a single platform on to which and from which he elevated and lowered himself, so that both feet were alternately on the platform and on the floor. At least 15 minutes elapsed between each work load test. Prior to the commencement of the test the subject was instructed in the performance of the test. He was allowed to steady himself by gripping a crossbar which, however, was not to be used in assisting his stepping up and down. …