Abstract
That previously confined dogs when exercised for a few days undergo a loss of blood volume erythrocytes and hemoglobin has been shown by Broun. 1 , 2 This loss he attributes to a process of fragmentation which other workers 3 have advocated as a normal mode of erythrocyte destruction. Thörner 4 , 5 has reported an increase in the osmotic resistance of erythrocytes of man and dog after a period of training. This he explains by a “weeding out”through mechanical fragmentation of less resistant corpuscles. Hastings 6 has shown that in vivo hemolysis occurs in the serum of untrained dogs after exercise. Broun's dogs showed recovery of hemoglobin and erythrocytes with continued training and of blood volume after 3 weeks′ rest. Anoxemia by anemia has been suggested as the bone marrow stimulant in the recovery process, by Steinhaus. 7
The present work was undertaken to determine whether or not prolonged physical training will induce an increase of blood volume and erythrocytes, and if possible, to throw light on the hematopoietic stimulant as well as the mode of blood destruction in exercise.
Five dogs were confined for 2 or 3 months without exercise and were then exercised for 2 hours daily over periods of 4 to 9 weeks′ duration. Observations on the blood were made throughout this time and continued for a few weeks after exercise was stopped. Two dogs swam in water at 30°C. for 2 hours and 3 ran on a treadmill set at 25% grade for a distance of 6 miles, daily. A constant mixed diet including 200 gm. of beef liver was fed daily beginning a month before control observations began and continuing throughout the exercise and post-exercise period.
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