Changes in the blood sugar and blood gases during exercise.

Abstract

It has been found by Scott and Hastings 1 that exercise causes a slight decrease in blood sugar and an increase in the oxygen content of the blood of dogs when they are made to work on an electrically driven horizontal treadmill at the rate of five miles an hour. We have made a study of the influence of exercise on the blood sugar and blood gases of several cats and one dog. The animals were exercised in a circular treadmill with a tread 5.75 meters long. Blood was collected under paraffin oil from an incision in an ear vein. The gases were analyzed immediately by Van Slyke's method of determining 2 the oxygen and carbon dioxide in one cubic centimeter of blood. Sugar was determined by the method of Hagedorn and Jensen. 3

Ten cats were studied in which the blood sugar alone was determined. With five other cats and the dog the sugar, oxygen and carbon dioxide of the blood were determined. In the latter set, two or three experiments were performed with each animal. In all but one case the cats were exercised by driving the treadmill by hand. The animals usually worked from ten to thirty minutes travelling from 500 to 1500 meters. In every instance where this was done, the blood sugar invariably increased more than 100 per cent, occasionally as much as 400 per cent. In these ex-periments the carbon dioxide was lowered markedly, commonly to twelve volumes per cent and occasionally as low as eight volumes per cent. This was apparently caused by the very rapid breathing accompanying the strenuous exercise. The oxygen was at first increased and then later decreased in some experiments.