Effect of training on plasma catecholamines in post myocardial infarction patients

Exercise induced plasma catecholamine levels, of post myocardial infarct patients, were compared before and after a 27 week training program in two groups. Heavy Intensity Exercise (H.I.E.) and Light Intensity Exercise (L.I.E.). The men (age 38-54 years) were exercised on a bicycle ergometer at constant submaximal work loads (test load) and to a symptom limited maximum work load, both before and after the training program. Forearm venous samples were obtained after 30 minutes rest and within 3 minutes of completion of the test load. After training a significant increase in both maximum work load and heart rate (P less than 0.05) was observed in the H.I.E. group. At the test load these individuals had a small (6%) decrease in heart rate. No significant changes were observed in the L.I.E. group at submaximum or maximum exercise. Prior to training, exercise resulted in a significant increase in norepinephrine (NE) with no change in epinephrine (E). Training resulted in a significant reduction (P less than 0.05) in the NE response at the test load of the H.I.E. group while no change was found in the L.I.E. group. Endurance jogging reduced the sympathetic response to moderate exercise.