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Biomedical subjects

R Rost

Publications and source records attributed to R Rost.

At least 55 records · Page 3Linked to original sources
PubMed1990

[Cross-country and downhill skiing in patients with myocardial infarct. Can silent ischemia be prevented by drug therapy?].

The appearance of ST segment depression in the exercise ECG serves as a threshold criterion when it comes to determining the "loadability" of myocardial infarction patients carrying out sports activities. In 27 MI patients, the question was investigated as to the extent to which abnormalities taking the form of silent ischemic episodes could be found during cross-country skiing on plains or during downhill skiing at an altitude of 800 to 2,000 meters. Such silent ischemic attacks were found in 20 out of the 27 patients. Both the duration and incidence were higher during sports activities than during normal day-to-day activities. The heart rate at the time of the appearance of the ischemic episodes was lower in the 12-hour ECG than during ergometry. During sports activities, however, the heart rates were frequently higher than the given training pulse rates. Treatment with nitrates (Isoket retard 120 mg) reduced the incidence and duration of silent ischemias. On account of the spontaneous variability of the parameter, it needs to be interpreted with caution. The incidence of silent ischemic episodes during sports activities in patients with clinical anomalies should prompt a rigorous treatment with drugs, and careful supervision of training.

Coronary Disease↗
PubMed1989

[The behavior of arterial blood pressure in dynamic and static muscle exercise with respect to atrial natriuretic peptide and neurotransmitters].

The development of the first semi-automatic blood pressure measuring instrument including optic and acoustic registration of systolic and diastolic blood pressure has led to a reliable assessment of arterial blood pressure during increasing ergometer exercise. There is a linear connection between workload intensity and systolic pressure. Intraarterially and noninvasively obtained values are identical with regard to systolic behavior. In principle, the intraarterially measured diastolic blood pressure, too, increases in healthy subjects, which, nevertheless, may often not be demonstrated in such a clear way due to artefacts occurring during blood pressure measuring. There are no significant differences between untrained and endurance-trained subjects at a given work load. Persons exhibiting a better performance capacity only reach higher maximal systolic values. The male and female subjects' regression lines significantly differ--the reason possibly being the woman's smaller muscle mass. Age-induced differences, too, are significant. Bodybuilders with extremely developed muscle mass do not show any significant differences with regard to blood pressure behavior during exercise. When establishing a relation to the relative muscle force the bodybuilders show blood pressure values even lower than normal values.

Animals↗
PubMed1987

Physical exercise and antihypertensive drugs.

Interactions and interrelations between antihypertensive drugs (AHD) and physical exercise are discussed on the basis of experimental results and of literature data. In physically active subjects AHD should lower the arterial pressure not only at rest, but also during physical stress. On the other hand, antihypertensive treatment should not influence physical performance. The main groups of AHD which could by applied in predominantly young and otherwise healthy subjects are: Beta-receptor blockers are recommended as first choice since they have a marked lowering effect on exercise blood pressure, conversely they impair by the same mechanism sympathetic stress adaptation. The effect of diuretics and calcium antagonists on exercise pressure is generally small; however, it may vary greatly in individual cases. As an interesting new category ACE-inhibitors should be studied further. Most AHD may impair the performance capacity of competitive athletes; however, sometimes they are also used illicitly to improve performance. In contrast, the symptom-limited performance of hypertensives is generally improved by therapy.

Antihypertensive Agents↗
PubMed1987

[Exercise hypertension--significance from the viewpoint of sports].

Exercise hypertension refers to an increase in blood pressure during dynamic exercise in excess of the limits in normotensive persons or those with borderline hypertension at rest as well as a disproportionately excessive increase in pressure in hypertensive persons in whom otherwise the increase in exercise pressure is shifted parallel to that of normotensive persons. There is no consensus for the absolute definition of exercise hypertension but traditionally, in sports medicine, systolic blood pressure values of 200 mmHg and more at a workload of 100 watts are considered abnormal. On the basis of the results of a study we performed in 2972 individuals, norms for exercise arterial blood pressure were constructed and found to be related to workload intensity as well as age. In contrast, there was no relationship between exercise blood pressure and exercise capacity or sex. In this regard, indirectly measured diastolic blood pressure is not reliably indicative of the actual prevailing pressure, particularly at higher workloads; it is, therefore, not considered to be useful in detection of exercise hypertension. In agreement with other studies, we found that up to one-third of all patients with normal blood pressure at rest but exercise hypertension eventually developed hypertension at rest. The incidence tended to increase with increasing age. Accordingly, exercise hypertension may be regarded as a precursor to established hypertension at rest.(ABSTRACT TRUNCATED AT 250 WORDS)

Antihypertensive Agents↗
PubMed1986

Cardiovascular effects of extreme physical training.

After a short historical remark the development of athlete's heart in childhood is described. Within 2 years significant differences were observed between endurance-trained (swimming) and untrained girls and boys determined by X-ray and echocardiographical examinations. The limits of the physiological size in relation to body weight were not exceeded within 10 years of longitudinal studies. A second point deals with athlete's heart from physiological and clinical viewpoints. The largest healthy heart ever found in our examinations of athletes had a size of 1,700 ml. Sixteen years after stopping the active career it was reduced to 950 ml without a pathological finding. Questionable and pathological cases are described. A third chapter covers the blood supply of internal organs during exercise combined with air or oxygen breathing. In this connection liver, kidneys, heart, lungs, and brain have been investigated. The reduced blood supply of the liver and kidneys during intense exercise on the cycle ergometer was not influenced significantly by inspiration of oxygen. A significant blood volume increase of the lungs was noticed during incremental rates of work. Exercise augmented also blood flow of the brain in relation to the work rate (at 100 W a 27% increase in grey matter flow of the right hemisphere). A fourth chapter deals with new hormonal and neurohormonal aspects related to the cardiovascular system. Beta-endorphines remained unchanged at work rates below the anaerobic threshold but increased significantly during maximal rate of work. The opiate antagonist naloxone abolished the rise in body temperature seen during ergometer exercise. The serotonin antagonist ketanserin lowered the blood pressure and the arterial lactic acid level during an incremental exercise test, similar to the results with the dopamine agonist pergolide. The hormone cardiodilatin is produced in the atrial appendages, and it is a potent substance in the regulation of the cardiovascular system. The adaptive reaction of the sympathetic nerve fibres in the myocard revealed different directions: activation, degeneration, and regeneration. These findings correlated highly significantly with the total amount of catecholamines in the heart muscle.

Adult↗
PubMed1985

[Preventive cardiology: lack of exercise and physical training from the epidemiologic and experimental viewpoints].

A survey is given on epidemiological and experimental results of lack of exercise as a risk factor for coronary heart disease. The consequences of endurance training are described. It is evident that endurance sport or training during leisure time can have a greater effect than heavy muscular professional work. The selectively analysed factor "lack of exercise" may be less important as a risk factor than the protective influence of endurance training. Directions are given for carrying out a preventive program of training, with contraindications included.

Adrenergic beta-Antagonists↗
PubMed1985

[Effects of various beta-receptor blockers on metabolic and circulatory parameters during physical exertion].

For further elucidation of the effect of various beta-adrenoceptor blockers on metabolism during exercise investigations on the influence of 5 beta-adrenoceptor blockers were carried out in healthy subjects. The 5 beta-adrenoreceptor blockers (acebutolol, metoprolol, penbutolol, pindolol, propranolol) were different regarding cardioselectivity and intrinsic activity (ISA). Each substance was given in 4 different dosages corresponding to 10:20:40:80 mg propranolol. Exercise was performed as bicycle ergometer test over 1 hour. In order to find out different effects during long-term application a medium dosage corresponding to 40 mg propranolol was applied for 4 weeks after the acute trials. The following parameters were measured: heart rate, systolic arterial pressure, parameters of carbohydrate metabolism (glucose, lactate) as well as lipid metabolism (free fatty acids (FFA), cholesterol, triglycerides etc.), serum concentration; for three beta-adrenoceptor blockers hormonal concentrations (catecholamines, insulin, human growth hormone (HGH), adrenocorticotrophic hormone (ACTH] were assessed. The different beta-adrenoceptor blockers demonstrated a varying relation between dosage and effect which was mostly pronounced for propranolol. All beta-adrenoceptor blockers caused a nearly complete blockade of energy release from FFA, and serum glucose concentration decreased. These changes were smaller under the effect of a low dosage of the cardioselective beta-adrenoceptor blocker metoprolol. The hormonal concentrations demonstrated a more pronounced increase of epinephrine during beta-blockade in contrast to only small changes by norepinephrine. Whereas there was no effect to be found on ACTH, HGH increased significantly under beta-blockade but independent of cardioselectivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1985

[Significance of sports for the heart of the elderly].

The changes in performance of cardiopulmonary metabolic parameters during aging are discussed. With advancing age, maximal oxygen uptake, the aerobic-anaerobic threshold, maximal attainable pulse rate, maximal stroke volume, and maximal peak flow all decrease. The causes are a reduction in the windkessel function of the aorta, loss of elasticity in the arteries, and silting of the peripheral capillaries, as well as other unidentified factors. The lower the aerobic-anaerobic threshold, the greater the reduction in blood flow through the liver and kidneys at given levels of load. This applies particularly to older individuals. The pulmonary circulation increases in inverse proportion to the maximal oxygen uptake value at submaximal load. Cerebral blood flow increases highly significantly in all parts of the left hemisphere at a measured work load of only 25 W, and the further increase at 100 W is again significant. The increase is greater in the gray matter than in the white matter. The maximal minute volume under load runs parallel to the maximal oxygen uptake curve with increasing age. Simultaneously, maximal diffusion capacity decreases and there is a reduction in the quality of distribution and perfusion. The result is an age-related decline of partial oxygen pressure in arterial blood. With advancing age there is an earlier rise in blood catecholamine levels, whereas the density of adrenoreceptors apparently changes only slightly, although their sensitivity decreases. Essentially, 55- to 70-year-old subjects who have gone for decades with no training are as trainable as untrained subjects in the third decade of life. This is true for all the parameter mentioned above. In contrast to younger subjects, muscle biopsies show an increase in activity not only of oxidative enzymes, but also of anaerobic enzymes (e.g., LDH). There is no increase in heart size after 8-12 weeks training. At rest and at given loads, there is an increase in stroke volume accompanied by a reduction in heart rate; peripheral resistance also decreases significantly. The heart of an older person participating in active sport could be placed at risk by inadequate training, but possibly also by excessive demands on intensity and duration.

Aged↗