Effects of Exercise on Goxsackie A9 Myocarditis in Adult Mice.

SummaryA cardiotropic strain of Cox-sackie A9 virus was inoculated intraperitone-ally into groups of adult C3H mice, one-half of which were vigorously exercised daily by swimming. Uninfected controls were studied in parallel. Among the infected mice, the virus was isolated in high titer from the hearts of a significantly greater proportion of those that were exercised. The possible mechanisms by which exercise could augment replication of virus in the myocardial tissue were discussed. On the ninth day after inoculation, the weight and relative weight of the heart were significantly greater in the exercised mice than in those that were not exercised. Among the exercised animals, the the weight and relative weight of the heart were significantly greater in those that were infected with virus than in those that were not infected. The increase in weight could not be attributed to increased water content or to inflammatory infiltrate.The technical assistance of Elaine Jeannotte is gratefully acknowledged.