The Relationship of Radiation Dose to Lethality Among Exercised Animals Exposed to Roentgen Rays

Abstract

The mortality of exercised, irradiated rats was compared with that of non-exercised irradiated rats following X-ray doses ranging from 200 to 1000 r. Swimming to exhaustion under standard conditions of testing constituted the exercise. Where exposure to X-rays is followed by daily exhaustive exercise, the mortality is significantly greater than with irradiation alone. The calculated median lethal dose of X-rays for non-exercised animals is 28% higher than that calculated for exercised animals. Several deaths occurred among exercised animals at a radiation dose which was not lethal for non-exercised animals. The mortality is not affected by exercise undertaken prior to irradiation. Expts. demonstrated the fact that the specific environment associated with the method of exercise is not responsible for the mortality increase observed with exercise.