losartan-potassium and Bradycardia

Doping consists in the use of artificial means or substances with the unique aim of improving performance despite adverse effects on health. Amphetamines stimulate the central nervous system by increasing motivation and vigilance. Often consumed in association with analgesics, they increase the fatigue threshold during prolonged or repeated exercise. Addiction and dependency to these substances are extremely rapid. Side-effects include insomnia, exhaustion, violence and can lead to serious heart diseases. By enhancing capacity for intensive training, anabolic steroids improve strength, alertness and speed. This action is often further strengthened by the use of growth hormones DHEA and IGF-1. Extremely high dosage is used and is in no way comparable with natural secretions or those necessary to re-balance an exhausted glandular system. During prolonged endurance exercise, doping aims at improving the circulation of oxygen in the blood and thus its availability to the muscles. Firstly, the blood haemoglobin concentration was increased by blood transfusions. At present the production of red blood cells is stimulated by repeated injections of exogenous erythropoietin. The extreme viscosity of the blood leads to a risk of vascular thromboses and high blood pressure and accentuates greatly and sometimes even fatally the possibility of brachycardia which is common with sportsmen.

Topics: Amphetamines; Anabolic Agents; Bradycardia; Cardiovascular Diseases; Doping in Sports; Erythropoietin; Fatigue; Growth Hormone; Humans; Hypertension; Thrombosis

Hypoxia-induced increases in red blood cell production have been found in both altitude-adapted populations and acclimatized lowlanders. This process is mediated by erythropoietin (EPO) released mainly by the hypoxic kidney. We have previously observed high hemoglobin concentrations in elite breath-hold divers and our aim was to investigate whether apnea-induced hypoxia could increase EPO concentration. Ten healthy volunteers performed 15 maximal duration apneas, divided into three series of five apneas, each series separated by 10 min of rest. Apneas within series were separated by 2 min and preceded by 1 min of hyperventilation to increase apnea duration and arterial oxygen desaturation. When EPO concentration after serial apneas was compared to baseline values, an average maximum increase of 24% was found (P < 0.01). No changes in EPO concentration were observed during a control day without apnea, eliminating possible effects of a diurnal rhythm or blood loss. We therefore conclude that serial apneas increase circulating EPO concentration in humans.

Topics: Adult; Apnea; Bradycardia; Carbon Dioxide; Diving; Erythropoietin; Female; Humans; Hypoxia; Male; Oxygen; Physical Fitness; Spirometry

There are no clear criteria for administration of blood to premature infants. In the past, indications for transfusion have included tachypnea, tachycardia, poor weight gain, apnea, bradycardia, pallor, lethargy, decreased activity, or poor feeding. Some have suggested that erythropoietin levels may also be useful in determining the need for transfusion. Data were studied from 11 premature infants with birth weights less than 1500 g collected throughout 469 hospital days. During that period the infants received a total of 37 blood transfusions. No overall relationship was found between hematocrit of 19% to 64% and heart rate, respiratory rate, or the occurrence of bradycardia; ie, these variables proved to be clinically unreliable as indicators of hematocrit. Furthermore, no predictable effect of transfusion could be identified on heart rate, respiratory rate, or on the incidence of apnea or bradycardia. It was anticipated that frequent episodes of apnea or bradycardia might increase serum erythropoietin concentration. To the contrary, more frequent bradycardia was associated with the low erythropoietin levels because those infants tended to receive transfusions for "symptomatic" anemia. The data are consistent with the concept that "anemia of prematurity" is not predictably associated with symptoms classically attributed to anemia. Possible reasons for this are that the premature infant has a different inherent response to anemia; that it is inappropriate to extrapolate symptoms of severe acute anemia to persons with mild or moderate chronic anemia; or, most likely, that other determinants of heart rate, respiratory rate, and apnea/bradycardia are of more importance than mild or moderate anemia.

Topics: Anemia; Apnea; Blood Cell Count; Blood Transfusion; Bradycardia; Erythrocyte Transfusion; Erythropoietin; Female; Gestational Age; Heart Rate; Hematocrit; Humans; Infant, Low Birth Weight; Infant, Newborn; Infant, Premature; Male; Respiration