Cardiac adaptations to chronic exercise in mice

Use of C57/Bl6 adult female mice to characterize the cardiac responses to chronic physical exercise such as swimming reveals that the chronic exercise induces cardiac hypertrophy in the mice without any increase in myofibrillar adenosinetriphosphatase function, cardiac tissue norepinephrine level or cardiac myosin ATPase activity. Swimming, however, elevates the heart weight by 10% and the heart weight-to-body weight ratio by 16%, while the heart rate response is reduced by 20%. The effects of chronic conditioning are suitable for murine models that facilitate the molecular analysis of in vivo adaptive cardiac hypertrophy.