Duration-controlled swimming exercise training induces cardiac hypertrophy in mice

Braz J Med Biol Res. 2003 Dec;36(12):1751-9. doi: 10.1590/s0100-879x2003001200018. Epub 2003 Nov 17.

Abstract

Exercise training associated with robust conditioning can be useful for the study of molecular mechanisms underlying exercise-induced cardiac hypertrophy. A swimming apparatus is described to control training regimens in terms of duration, load, and frequency of exercise. Mice were submitted to 60- vs 90-min session/day, once vs twice a day, with 2 or 4% of the weight of the mouse or no workload attached to the tail, for 4 vs 6 weeks of exercise training. Blood pressure was unchanged in all groups while resting heart rate decreased in the trained groups (8-18%). Skeletal muscle citrate synthase activity, measured spectrophotometrically, increased (45-58%) only as a result of duration and frequency-controlled exercise training, indicating that endurance conditioning was obtained. In groups which received duration and endurance conditioning, cardiac weight (14-25%) and myocyte dimension (13-20%) increased. The best conditioning protocol to promote physiological hypertrophy, our primary goal in the present study, was 90 min, twice a day, 5 days a week for 4 weeks with no overload attached to the body. Thus, duration- and frequency-controlled exercise training in mice induces a significant conditioning response qualitatively similar to that observed in humans.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological
  • Animals
  • Blood Pressure
  • Cardiomegaly / etiology*
  • Cardiomegaly / pathology
  • Citrate (si)-Synthase / metabolism
  • Heart Rate
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Muscle, Skeletal / enzymology
  • Physical Conditioning, Animal*
  • Physical Endurance
  • Swimming*
  • Time Factors

Substances

  • Citrate (si)-Synthase