A simple quantitative “two-step” test of myocardial function is described, and tables of climbs are given for normal individuals, from four to seventy-four years of age, of both sexes. The patient's weight multiplied by the number of ascents gives the foot pounds of work per minute. Not only may it be learned in this way whether the exercise tolerance of an individual is within average figures, but his actual limit may be ascertained. The percentage of efficiency is calculated by dividing the number of climbs the patient can actually perform by his theoretical limit, as derived from the tables.

Men have greater exercise tolerance than women. The maximum of this tolerance appears to be about 3,800 foot pounds of work, in men between twenty-two and thirty-one years of age weighing from 170 to 200 pounds. The maximum for women appears to be 3,000 foot pounds of work performed between the ages of twenty and twenty-seven by individuals whose weight is about 150 to 180 pounds. Older and heavier men and women show a decline in exercise tolerance. Children show the greatest efficiency, that is, the number of ascents possible in the given time is highest in the young. There is a sharp rise until puberty, then the slope is more gradual until the twenties are reached.

Thyroid extract, ephedrine, alcohol, excessive smoking, and upper respiratory infections affect the results.

The test is a definite aid in the diagnosis and evaluation of cardiovascular disease and in deciding how much work, or sport, or other activity the patient may be permitted. It also helps to differentiate functional and organic disease of the heart and is particularly useful in the anginal syndrome.

The measure of exercise tolerance determined by the two-step test is a fairly constant figure from day to day, and, unless one is in athletic training, similar results are common in those who lead a sedentary and those who live an outdoor life.

The exercise tolerance test may be the only objective evidence that the myocardium is involved.

The exercise test is not a strain, and no untoward results, even in cases of anginal syndrome, have ever been observed.

Clinical experience, mathematical deduction, and physiological reasoning appear to prove that the test is an index of myocardial function.