Die invloed van inoefening op die hormonale sekresie by postkoronêre persone met spesifieke verwysing na insulien, groeihormoon en kortisol

Abstract

Physical activity has been used at an increasing rate with worldwide recognition as a practical method of rehabilitation for persons who have survived an episode of myocardial infarction. Research was and is still conducted in the field of the coronary risk factors with some significant and contradictory results. Many questions are partially unanswered, especially concerning the presence and influence of hormones after an incident of myocardial infarction, as well as its interrelationship with other factors also present. It is furthermore of great importance to evaluate the influence of programmed training on the hormonal response of insulin, growth hormone and cortisol, which are found present after an incident of myocardial infarction. Research was conducted to evaluate the influence of a training program on several hemodynamic and hormonal parameters of persons who had suffered and survived a heart attack. A group of 13 men with a mean age of 47,6 years participated in an eight month, individually prescribed physical rehabilitation program on bicycle ergometers. All of them had had one or two incidents of uncompleted myocardial infarctions within two years prior to the start of the research project. Before the start of the project they were all examined by a specialist physician and only on his approval were they allowed to participate in the research program. Each individual had to complete a multistage physical work capacity test of standardized intensities, where after a training program was constituted according to the protocol of Lange Andersen (1971). Several cardiovascular and biochemical parameters were t es ted before and after the physical conditioning program. The tests included heart rate, blood pressure, myocardial function via the double product, glucose tolerance and the serum values of insulin, growth hormone and cortisol during a glucose tolerance test. Training had a significant influence on all the cardiovascular parameters, especially in the case of the myocardial function. The same effect occurred in the glucose tolerance test. Of significant importance was the shifting of the maximal turning point of the blood-glucose concentration from 60 minutes to 30 minutes. A normalising effect was also observed in the glucose tolerance due to the influence of training. Insulin and growth hormone showed the same normalising effect which was produced by physical training. A statistically significant difference was observed between the pre- and post training values of certain levels of the mentioned hormones during the glucose tolerance test. No statistically verified difference occurred in the cortisol concentration, although a normalising effect caused by the

physical training program was observed in some cases. It may be concluded that physical activity as mentioned in this study has a therapeutical and beneficiary effect on the physiological and biochemical consequences of the post coronary patients.