ISSN:0195-9131    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

A. GROSSMAN and J.R. SUTTON. Endorphins: What are they? How are they measured? What is their role in exercise?Med. Sci. Sports Exerc., Vol. 17, No. 1, pp. 74–81, 1985. A generalized knowledge of opiates has been available for centuries, but it was not until 1975, following the isolation of the first endogenous opioids, that it was appreciated that their analgesic properties were mediated via specific receptors. Three general classes of opioids are now recognized: the endorphins, the enkephalins, and the dynorphins. Assaying of the endogenous opioid peptides has never been simple, and now radioimmunoassay has replaced the earlier bioassays. When coupled with immunohistochemical techniques, radioimmunoassay allows precise localization of opioids in various tissue sections. There is evidence that plasma concentration of endorphins, and possibly also met-enkephalin, increases with exercise. In addition, the opioid peptides have important implications for the effects of other hormonal functions, including the pituitary hormones and catecholamines. Few studies during exercise are available, and naloxone has been used widely as the agent to determine the role of endogenous opioids on hormonal secretions. Slightly conflicting results have been obtained, depending on the dosage of naloxone used. With high-dose naloxone, there appears to be overall endorphin inhibition of cortisol, prolactin, and growth hormone secretion. Endorphins do not appear to exert a major influence on the cardiovascular response to exercise, but in high-intensity exercise, they appear to partially inhibit the ventilatory response to exercise.

ISSN:0195-9131    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

J.W. McARTHUR. Endorphins and exercise in females: possible connection with reproductive dysfunction.Med. Sci. Sports Exer., Vol. 17, No. 1, pp. 82–88, 1985. Currently available measurements of β-endorphin and β-lipotropin in exercising women are in excellent agreement and indicate a 2–3 fold increase over basal levels. Possible effects of exercise upon the transfer of endorphins from the peripheral circulation to the brain are examined, and evidence is presented that suggests the occurrence of a concomitant exercise-related increase of endorphins in both humoral and central nervous system compartments. Steady-state measurements of circulating luteinizing hormone and follicle-stimulating hormone levels in oligo-amenorrheic athletes, on the other hand, do not agree. It is felt that the lack of consensus may be attributable partly to technical inadequacies and partly to lack of awareness of the need for frequent sampling. The bulk of the findings suggest a tendency for luteinizing hormone levels to be low and follicle-stimulating hormone levels to be normal or low, a pattern compatible with repeated activation of the CRH-ACTH-POMC system as a result of exercise.

ISSN:0195-9131    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

P.A. Farrell. Exercise and endorphins—male responses.Med. Sci. Sports Exerc., Vol. 17, No. 1, pp. 89–93, 1985. The discovery of the endogenous opiates in the mid-1970's has led to a tremendous scientific effort attempting to determine the physiological role of these peptides. An increase in the peripheral plasma levels of β-endorphin in humans after exercise has been noted by all investigators to date. This indication that the endogenous opiate system is activated during exercise should stimulate investigators to use exercise and training as models to aid in the understanding of these peptides. Unlike most other endocrines, plasma levels of β-endorphin do not increase proportionally to work intensity. This conclusion is based on only one study and requires corroboration. All human studies to date have used radioimmunoassays, with one exception, and interestingly that study showed no consistent change in plasma levels of leucine enkephalin-like radioreceptor assayable ligands. In males, essentially no information is available concerning the effects of training on either acute or chronic responses to exercise. Studies using opiate antagonists (receptor type-specific) in human and animal models should prove useful in establishing or disproving roles for these peptides in appetite, pain perception, temperature regulation, metabolism, ventilation, and blood pressure control during exercise.

ISSN:0195-9131    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

W.P. MORGAN. Affective beneficence of vigorous physical activity.Med. Set. Sports Exerc., Vol. 17, No. 1, pp. 94–100, 1985. Vigorous exercise is associated with a sensation of well-being, and this subjective state has been objectively quantified with psychometric, cardiovascular, and neurophysiological data. Reductions in state anxiety have been demonstrated to follow acute physical activity, and this response persists for 2–5 h. Chronic physical activity has been associated with reductions in anxiety and depression, as well as increases in self-esteem. This research has been limited to designs of a correlational nature, and the issue of causality vs mere association has not been resolved or addressed. Three hypotheses based upon distraction, monoamine metabolism, and endorphin release are discussed in this paper. Investigators have traditionally attempted to illustrate the mechanism involved in improved mood following exercise by testing one of these or related hypotheses, but it is likely that advances will not be made in this area until these hypotheses are examined in a multiple or synergistic manner. It is concluded that each of the hypotheses reviewed remains tenable.

ISSN:0195-9131    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

A. GROSSMAN. Endorphins: “opiates for the masses.”Med. Sci. Sports Exerc., Vol. 17, No. 1, pp. 101–105, 1985. Endogenous opioid peptides rose to prominence with the discovery of the enkephalins in 1975. Since then, a vast amount of research has been directed toward understanding their role in normal and pathophysiological situations. Although the place of endogenous opioids in psychiatry remains uncertain, there is good evidence that a variety of tumors may secrete endorphins or enkephalins, and these may contribute to the non-metastatic complications of malignant disease. In addition, changes in cerebrospinal fluid met-enkephalin and β-endorphin after acupuncture may be involved in the effectiveness of this therapy in the treatment of heroin withdrawal and severe pain. The hormonal effects of opiate agonists and antagonists are now well characterized; exercise-induced changes in circulating catecholamines are markedly enhanced by the opiate antagonist naloxone. It is possible that the opiate inhibition of catecholamine release during exercise is a reflection of endogenous opioid modulation of effort perception.

ISSN:0195-9131    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

J.H. WILMORE, A.E. ATWATER, B.D. MAXWELL, D.L. WILMORE, S.H. CONSTABLE, and M.J. BUONO. Alterations in breast morphology consequent to a 21-day bust developer program.Med. Sci. Sports. Exerc., Vol. 17, No. 1, pp. 106–112, 1985. Normal menstruating females, 19 to 32 years of age, were randomly assigned to either a control (C;N= 17) or an experimental (E;N= 17) group to determine alterations in breast size, shape, and volume consequent to a 21-day bust development program (BDP) using a commercial exercise device as specified by the manufacturer. E and C groups were evaluated on 2 consecutive d prior to initiating the BDP to establish reliability of the test procedures and again at the end of the BDP, 27 to 29 d following the initial measures. Anthropometric measures included the following girths: shoulder, chest, bust with and without brassiere, abdomen, deltoid, and flexed biceps. Breast photography included two 35-mm photographs each from the side and front views, in both full inspiration and full expiration, with the subject position carefully standardized. A total of 10 measurements, corrected for perspective error, were obtained from these photographs. Breast volume was measured using a water displacement technique, with three trials for each breast. Repeated measures analysis of variance procedures indicated no significant differences consequent to the BDP for any of the variables assessed, with the exception of a small decrease in shoulder girth in both E and C and a small decrease in left breast volume in E. It was concluded that the use of a commercial exercise device with a specific BDP does not result in changes in breast size, shape, or volume.

ISSN:0195-9131    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

J.P. Després, C. Bouchard, A. Tremblay, R. Savard, and M. Marcotte. Effects of aerobic training on fat distribution in male subjects.Med. Sci. Sports Exerc., Vol. 17, No. 1, pp. 113–118, 1985. To investigate the effects of aerobic training on adipose tissue morphology and fat distribution, several indicators of body fatness (percent body fat, seven subcutaneous skinfolds, fat cell weight) were assessed in 13 sedentary male subjects (SS) submitted to a 20-wk aerobic training program and in 20 male long-distance runners (LDR). The LDR subjects had a mean ± SD &OV0312;Cmaxof 65.9 ± 6.5 ml±mhr-1·kg-1and averaged 120 km·wk-1. Training increased the &OV0312;O2maxvalues of the SS group significantly (pre: 41.9 ± 7.0 vs post: 53.4 ± 6.4 ml-kg-1min-1;P< 0.001) and decreased significantly percent body fat (P< 0.01), sum of skinfolds (P< 0.01), and fat cell weight (P< 0.05). Trunk skinfolds were more altered by training than extremity skinfolds, with reductions of 22 and 12.5%, respectively. Significant correlations were found between fat cell weight and percent body fat in SS before and after training (r= 0.75;P< 0.01), while no significant relationship was noted in the LDR group. Moreover, using the sum of skinfolds divided by percent fat or by fat mass to reflect the proportion of subcutaneous fat to total fat, the LDR subjects exhibited less subcutaneous fat than the SS group (P< 0.01) and training did not alter these ratios in the SS group. These results suggest that 20 wk of aerobic training can alter body fatness in men but that the induced fat loss does not seem to deplete preferentially subcutaneous fat.

ISSN:0195-9131    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

R.B. VOGEL, C.A. BOOKS, C. KETCHUM, C.W. ZAUNER, and F.T. MURRAY. Increase of free and total testosterone during submaximal exercise in normal males. Med. Sci. Sports Exerc., Vol. 17, No. 1, pp. 119–123, 1985. The serum levels of testosterone, free testosterone, prolactin, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) were measured at rest, during 45 min of exercise on a bicycle ergometer at 50% of the subjects' previously determined maximal oxygen uptake (&OV0312;O2max), and during a 30-min recovery period. Ten healthy, untrained males were used as subjects. Mean serum testosterone levels increased significantly (P< .05) over resting values at 15 min of exercise. Mean peak serum testosterone and free testosterone were significantly (P< .01) increased during the exercise period as compared to resting values. No significant changes were measured for serum levels of LH, FSH, or prolactin during exercise. It appeared that bicycle exercise of moderate intensity significantly increased both free and total testosterone in untrained males.

ISSN:0195-9131    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

W.E. SINNING, D.G. DOLNY, K.D. LITTLE, L.N. CUNNINGHAM, A. RACANIELLO, S.F. SICONOLFI, and J.L. SHOLES. Validity of “generalized” equations for body composition analysis in male athletes.Med. Sci. Sports Exerc, Vol. 17, No. 1, pp. 124–130, 1985. Equations by Durnin and Womersley [(D-W),Br. J. Nutr32:77, 1974], Jackson and Pollock [(J-P),Br. J. Nutr. 40:497, 1978], and Lohman [(L),Human Biol, 53:181, 1981] for estimating body density (BD) purportedly overcome the problem of specificity by accounting for age and/or the curvilinear relationship between skinfolds (SF) and BD. Their equations were validated on 265 male athletes against percent fat measured by underwater weighing [(UWW); mean ± SD = 9.2 ± 4.4%]. Equations by Sloan [(S),J. Appl. Physiol23:311, 1967], Katch and McArdle [(K-M),Human. Biol. 45:445, 1973], and Forsyth and Sinning [(F-S),Med. Sci. Sports5:174, 1973] were included as “linear regression models” to compare to the curvilinear models of J-P, D-W, and L. Differences between UWW and estimated mean values ranged from −1.1 to +5.9%; correlations ranged from 0.58 to 0.85; SEE ranged from ±2.41 to ±3.61%; and total error (E) ranged from 2.38 to 6.97%. The seven D-W equations overestimated mean percent fat by from 3.9 to 5.9%. The K-M, S, and L equations overestimated by 1.3, 0.5, and 1.7%, respectively. The F-S equations overestimated by 2.4 to 3.8%. Of the 21 equations evaluated, only 3 by J-P gave estimates not significantly different from UWW percent fat. Regression analyses of the relationship between UWW (y) and estimated (x) percent fat values from those equations were:y= 1.037x− 0.08 ± 2.38, E = 2.38,r =0.84; 0.869x+ 1.36 ± 2.45, E = 2.51,r= 0.83; 1.107x− 1.14 ± 2.51, E = 2.53,r= 0.82. It was concluded that the three J-P equations were most accurate and suitable for body composition screening of male athletes. However, the estimations by the S, K-M, and L equations were within the error of the method.

ISSN:0195-9131    

出版商:OVID    

年代:1985

数据来源: OVID