摘要:

Thirty-six cases of heart attack or sudden death in marathon runners have been reported in the world literature to date. The mean age of the runners was 43.8 yr (range = 18 to 70), the mean years' running was 6.8 yr (range = 0.5 to 29), and the mean best standard 42.2 km marathon time was 3h 28min (range = 2h 33min to 4h 28min). Coronary artery disease was diagnosed either clinically, angiographically, or at autopsy in 27 runners (75%), two of whom also had histological evidence of hypertrophic cardiomyopathy. Seventy-one percent of the runners with coronary artery disease had premonitory symptoms, and most ignored such symptoms and continued to train or race. Fifty percent of all cardiac events occurred either during or within 24 h of competitive running events or long training runs.The marathon running population does not constitute solely persons with excellent cardiovascular health. Marathon runners, especially those with a family history of heart disease and other coronary risk factors, should not consider themselves immune to either sudden death or to coronary heart disease and should seek medical advice immediately if they develop any symptoms suggestive of ischemic heart disease. Physicians should not assume that “physically fit” marathon runners cannot have serious, life-threatening cardiac disease.

ISSN:0195-9131    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

The body composition and anthropometric characteristics of male paraplegic athletes (PARA,N= 22) were contrasted to an able-bodied ectomorphic (N= 22) and mesomorphic (N= 31) comparison group of moderately and highly trained male subjects. The validity of 12 body composition [density (Db)] prediction equations reported in the literature, 4 generalized, were determined (tested) on this special group of athletes (PARA). On the whole, the prediction equations over-predicted Dbin PARA by 0.0039 to 0.0166 g.cm3(under-predicted relative fat by 1.8 to 7.4%). Five diameter, 11 circumference, and 7 skinfold measures were used in a SAS-STEPWISE multiple regression procedure with hydrostatically determined Dbto develop several suitable Dbprediction equations for the paraplegic athlete. Diameters were poor predictors (r = 0.60, SEE = 0.0164), while skinfolds, circumferences, or a combination of measures were acceptable, with the combined equation being best (r = 0.95, SEE = 0.0064).The findings of this study suggest that even generalized equations do not adequately predict Dbin PARA and that paraplegic specific equations are presently best suited for predicting Dbin paraplegic athletes. The results further indicate that although these equations meet many of the criteria of Lohman, the SEE and total error values are unusually high and make prediction of body composition using anthropometry in a heterogeneous group of PARA athletes slightly unreliable.

ISSN:0195-9131    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

To investigate the effect of training-induced increases in plasma volume on maximal aerobic power, 8 male subjects (age 19 to 24 yr) underwent a 4-d training program (2 h.d−1at an estimated 71% maximal aerobic power. Following training, plasma volume measured using131-human serum albumin increased by 20.3% (P< 0.01) whereas red cell volume remained unchanged and total blood volume increased by 12.3% (P< 0.01). During progressive sub-maximal cycle exercise, oxygen consumption, carbon dioxide production, ventilation, and blood lactate concentration remained unchanged following the training whereas heart rate was significantly elevated (P< 0.05). Significant post-training elevations were also noted in carbon dioxide production (P< 0.05), blood lactate (P< 0.01), and peak power output (P< 0.05) during maximal exercise. Maximal aerobic power and ventilation were not altered. It is concluded that hypervolemia induced by short-term exercise training does not affect oxygen consumption either during sub-maximal or maximal exercise.

ISSN:0195-9131    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

The most commonly tested hypothetical cause of athletic amenorrhea has been low body fat, Test results have conflicted because of mixed groups of athletes and methodologic problems. In this study, we measured body fat only in distance runners (>53 km. wk−1) of the same sornatotype who clearly had regular menses or secondary amenorrhea; this permitted more valid group comparison of body fat using hydrostatic weighing. The regularly menstruating group (N= 7) had 12 periods. yr−1at intervals of 26.5 ± 1.0 (SE) days with a duration of 4.1 ± 0.4 days. In the athletic amenorrhea group (N= 7), menstrual periods had been absent for 1 to 10 yr (average = 3.9 ± 1.3 yr); they were gynecologically evaluated to restrict the group to those with athletic amenorrhea. The groups were similar in a number of categories: weight, height, age, menarchecal age, weekly training mileage, days/ week training, years of training, and maximum oxygen uptake. Percent body fat for the two groups was the same: 17.7 ± 2.1% for the amenorrheic athletes and 17.4 ± 1.2% for the regularly menstruating athletes (P= 0.91). These data do not support the idea that low body fat per se causes athletic amenorrhea.

ISSN:0195-9131    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

We used the Eating Attitudes Test and Eating Disorder Inventory as a measure of the incidence of anorexia nervosa in 125 female distance runners. The incidence of abnormal eating attitudes symptomatic of anorexia nervosa was 14% (18 runners). Of these, only five runners (4%) also had a low body mass and a past history of amenorrhea and only one subject (0.8%) had been treated for anorexia nervosa. Three of these five runners (60%) were elite marathon runncrsand one a highly ranked track athlete. The low incidence of anorexia nervosa in the total group does not support the Yates hypothesis that running is an analog of anorexia nervosa and therefore attracts persons with an anorexic personality. However, the study does show that it is the better athletes who are more likely to exhibit the physical and psychological features of anorexia nervosa.

ISSN:0195-9131    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

Nine healthy subjects were studied to determine their performance and the metabolic and hormonal responses to prolonged exercise after ingestion of a carbohydrate or a lipid diet. Subjects exercised on a bicycle ergometer (60% VO2max) until exhaustion four times at weekly intervals. The exercise test was performed I h after ingestion of three different isocaloric meals (400 Kcal) containing either glucose, medium-chain triglycerides (MCTs) or long-chain triglycerides (LCTs). The fourth test was performed after a night fast. The metabolism of these nutriments was followed using [U-13C]glucose, [l-13C]octanoate, and [l-13C]palmitate added as tracers.The average work time was comparable whatever nutriment used (116 ± 11 min). Oxidation of the ingested nutriment over this period was 80% for glucose, 45% for MCTs, and 9% for LCTs. Glucose ingestion produced an early insulin peak associated at the end of the exercise with a lower glycemia compared to the fat diets. After MCT ingestion, an increase in ketone bodies was observed. Catecholamine response to physical exercise was decreased by aII the meals when compared to fasting.Thus, we conclude that a different lipid meal, MCTs, or LCTs, compared to glucose feeding, do not modify exhaustion time in spite of differences in hormonal and metabolic responses.

ISSN:0195-9131    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

The purpose of this study was to examine the response of salivary cortisol to acute exercise, and to directly compare serum and salivary cortisol responses to sub-maximal exercise. Eight males volunteered to participate in the study. On three separate days following the assessment of maximum oxygen uptake (VO2max), the subjects exercised on a bicycle ergometer at 75% of their VO2maxfor 30 min. On a fourth day, the subjects rested quietly, and this served as a control condition. On each of these days, five serial samples of either blood, saliva, or both blood and saliva were obtained at 15-min intervals before, during, and after exercise. Sub-maximal exercise elicited a significant (P< 0.05) increase in both serum and salivary cortisol above resting control levels immediately and 15 min following exercise under all exercise conditions. In addition, significant correlations (allP< 0.01) were observed between serum and salivary cortisol at each of the five sampling periods. The correlations were as follows; r = 0.89 at −15 min; r = 0.60 at O min; r = 0.72 at 15 min; r = 0.90 at 30 min; and r = 0.93 after 15 min of recovery. Saliva was also obtained immediately before and 5 min following the assessment of &OV0312;O2maxand there was a significant (P< 0.05) increase in post-&OV0312;O2max. test (1.07 ± 0.12 Mg·dl−1) compared to pre-test (0.71 ± 0.06 ·g-dl−1) salivary cortisol levels. The results of this experiment indicate that salivary cortisol is a potentially valid measure of serum cortisol response to short-term cycling.

ISSN:0195-9131    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

The present study was undertaken to define the response of plasma β-endorphin immunoreactivity (ir-BE) to exercise of increasing intensity. Nineteen healthy males performed continuous exercise for 32 min on a cycle ergometer, comprised of 8-min bouts at %&OV0312;O2maxapproximating 25, 50, and 75% of maximal exercise. Venous blood samples were collected before exercise (T = −20 and 0 min), during exercise (T = 8, 16, 24, and 32 min), and in recovery (T = +15, +30 min). Ir-BE in plasma was measured by radioimmunoassay using Immuno Nuclear assay kits. Plasma ir-BE level (pg·ml−1) was not altered from pre-exercise (18.3 ± 1.3) after 8 min of exercise at 25 and 50% &OV0312;O2maxintensity; however, ir-BE rose significantly after 8 min of 75% &OV0312;O2maxwork intensity (27.1 ± 2.4) and was further elevated at maximal exercise (74.1 ± 8.6). Ir-BE level remained elevated 15 min (60.9 ± 8.1) and 30 min (35.2 ± 5.2) post-exercise. The response pattern was further characterized by a significant (P< 0.05) inter-individual variation, both at rest and during exercise; also, regression analysis indicated the ir-BE levels attained at maximal exercise were inversely related to the relative &OV0312;O2max(ml·kg−1·min−1) of the subject (predicted ir-BE = 248.2 – 3.39 &OV0312;O2max;r = –0.397,P< 0.05). It is concluded that the ir-BE response to exercise of increasing intensity is similar in nature to that of other stress-related hormones; these data suggest an exercise stress threshold level for increased ir-BE corresponding in this design to 50% < &OV0312;O2max< 75%. The observation of a significant inverse relationship in ir-BE at fatigue to maximal aerobic capacity was surprising and merits further investigation.

ISSN:0195-9131    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

To investigate if changes in circulating testosterone levels during isokinetic resistance exercise in women were similar to those during intense aerobic exercise and to examine concomitant changes in hemocon-centration, specific binding protein (sex hormone binding globulin-binding capacity), non-sex hormone binding globulin bound testosterone, luteinizing hormone, follicle-stimulating hormone, cortisol, and lactate, blood samples were obtained through an indwelling cannula at 30 and 15 min before exercise, after each of six exercises on upper and lower body muscle groups, and at 15 and 30 min after exercise in seven normal menstruating women. Investigations lasting approximately 60 min were performed in the early follicular phase beginning at 3.30 p.m. after two months of training with isokinetic (“Nautilus”) equipment. Baseline testosterone and non-sex hormone binding globulin bound testosterone levels were significantly higher in subjects than in a control group. Increased total and non-sex hormone binding globulin bound testosterone was observed immediately prior to exercise with further increases late in exercise, then with proportional increases in cortisol and lactic acid. Sex hormone binding globulin-binding capacity increased before exercise. The testosterone increments exceeded hemoconcentration. Luteinizing hormone and follicle-stimulating hormone levels increased during exercise. The data suggest that origins of the exercise-associated testosterone increment are complex, resulting from hemoconcentration and specific gonadal and adrenal responses.

ISSN:0195-9131    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

The purpose of this investigation was to evaluate the cardiovascular responses to rowing. In the first part of the study, heart rate (HR) and cardiac output (Q) were measured at rest and at three steady-state exercise levels on the variable-resistance rowing ergometer in 10 female and 11 male subjects. &OV0422; was determined non-invasively by the equilibration method of CO2re-breathing, and stroke volume (SV) was calculated. Subjects varied in rowing ability from healthy, inexperienced rowers to competitive athletes. The linear relationships between &OV0422; and oxygen consumption for the women (r = 0.57;P< 0.001; slope = 5.2 ± 1.1) (mean ± SD) and the men (r = 0.58;P< 0.001; slope = 6.1 ± 1.4) were similar to published values for other types of upright exercises. For both men and women, SV increased from rest to the first level of exercise, and then reached a plateau at or before the second exercise intensity. Between the second and third levels of exercise, SV decreased significantly in the female subjects (107 ± 18 vs 94 ± 16 ml;P< 0.05), but not in the male subjects (128 ± 1 I vs 126 ± 15 ml;P= not statistically significant). In the second part of the study, HR, &OV0422;, and SV were compared on the cycle and rowing ergometers on successive days in eight additional subjects. At similar levels of oxygen consumption and &OV0422;, HR was significantly higher, and SV was significantly lower during rowing exercise than with cycle exercise. These results demonstrate that the cardiovascular responses to rowing are different from upright cycle exercise. There was a greater reliance upon the increase in HR than the SV response to increase &OV0422; during rowing than during cycling.

ISSN:0195-9131    

出版商:OVID    

年代:1987

数据来源: OVID