摘要:

Currently there are no guidelines for exercise prescription for cardiac patients with repaired sternotomy. This study reports good results in a 63-yr-old patient with prolonged course of hospitalization following mediastinitis and discusses considerations required for safe participation in competitive sports.

ISSN:0195-9131    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

To investigate the anaerobic capacity in children with bronchial asthma, eight male children with atopic asthma (age: 12 ± 1.7 yr) and seven healthy control subjects (age: 12 ± 1 yr) performed a 30-s all-out exercise test: the Wingate anaerobic test (WanT). Post-exercise plasma epinephrine (E), norepinephrine (NE), venous blood lactate (La), and blood pH levels were determined. Peak power (Ppeak), mean power (Pm), and total energy expenditure (Wtot) during the WanT were assessed. The relative importance of aerobic (WO2) and anaerobic (Wana) energy release during the WanT was also evaluated. In comparison with control subjects, the children with asthma exhibited lower Ppeak (W·kg-1): 6 ± 1.14 vs 7.3 ± 0.5,P< 0.05; lower Pm (W·kg-1): 4.7 ± 0.8 vs 5.9 ± 0.5,P< 0.05; and lower Wtot (Jg-1): 140.3 ± 25 vs 176.9 ± 19,P< 0.05. The relative contribution of WO2(26%) and Wana (74%) to the Wtot was identical in both groups. Blood lactate and pH kinetics revealed significantly lower La values and less acidosis in the asthmatic group (P< 0.001). Lastly, E (pg·ml-1) concentrations were lower in the asthmatic group: 274.96 ± 84.58 vs 901.28 ± 604.76,P< 0.05. These results suggest a reduced anaerobic capacity in children with asthma. A diminished adrenergic response to exhausting exercise, leading to a decreased anaerobic glycolysis, could partly account for this phenomenon.

ISSN:0195-9131    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

This investigation examined the acute response of serum lipoprotein(a)(Lp(a)) concentration immediately after, and during several days following, level and downhill motorized treadmill running. Eight males ran for 1 h on a level motorized treadmill at an intensity producing 90% maximum heart rate(MHR). On a separate occasion, three males and three females performed downhill (negative 13.4% incline) treadmill running at an intensity producing 75-80% MHR. For both protocols, serial blood samples were taken pre- and post-exercise and at the same time of day 1, 3, 5, and 7 days following exercise. Levels of Lp(a), creating kinase (CK), C-reactive protein (CRP), and ferritin were measured. Repeated measures statistical analysis (Friedman ANOVA) showed no significant change in the median level of Lp(a) (level run, 5.0 mg·dl-1; downhill run, 7.45 mg·dl-1) across time following either protocol. After level running, ferritin levels 5 and 7 d post-exercise were significantly (P< 0.05) lower compared with immediately and 1 d post-exercise measures (Friedman ANOVA). Following level running, the Wilcoxon signed rank test showed significant (P< 0.05) elevations in CK levels immediately, 1 and 5 d post-exercise compared with pre-exercise values. Following downhill running, CK level was significantly elevated up to 3 d post-exercise (Wilcoxon signed rank). Calculated plasma volume did not change significantly following either protocol. These data suggest that Lp(a) does not change acutely in response to level or downhill treadmill running up to 60 min duration.

ISSN:0195-9131    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Bone mineral density (BMD) was compared between 7-11-yr-old female gymnasts(GYM:N= 16) with a history of high volume impact loading (minimum of 15 h·wk-1for past 2 yr) and healthy nonathletic controls(CON:N= 16). Whole body (WB) and regional areal BMD measures were determined by dual energy x-ray absorptiometry (DXA) normalized for height and body mass and also converted to bone mineral apparent density (BMAD). Volumetric BMD and bone cross-sectional areas were also measured by peripheral QCT (pQCT) at the left distal radius. GYM were significantly (P< 0.01) shorter (129.3 ± 5.7 vs 136.7 ± 4.4 cm; means ± SD) and leaner (15.1 ± 1.9 vs 19.6 ± 4.3% body fat from DXA), and had significantly (P< 0.05) greater femoral neck (0.698 ± 0.058 vs 0.648 ± 0.064 g·cm-2) and trochanter (0.616± 0.060 vs 0.530 ± 0.084 g·cm-2) areal BMD than CON. GYM also had significantly higher whole body (0.101 ± 0.009 vs 0.094 ± 0.007 g·cm-3), femoral neck (0.245 ± 0.060 vs 0.205 ± 0.049 g·cm-3) and lumbar spine (0.227 ± 0.014 vs 0.210 ± 0.026 g·cm-3) BMAD compared with CON. Height normalized areal BMD measures were also significantly higher at all sites in GYM. Radial total (367.7 ± 51.6 vs 307.4 ± 27.6 mg·cm-3), trabecular (207.9 ± 45.3 vs 163.8 ± 31.4 mg·cm-3), and cortical (496.9 ± 67.5 vs 429.8 ± 33.8 mg·cm-3) BMD were also significantly greater in the GYM compared with the CON. In conclusion, high volume impact loading was associated with greater (compared with controls) whole body and regional bone mineral density in pre-adolescent female gymnasts.

ISSN:0195-9131    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Catecholamine and lactate responses to incremental exercise were examined in individuals with spinal cord injury (SCI). Three men with high-level (HINJ) and four with low-level (LINJ) SCI performed ˙VO2peakexercise tests on an arm ergometer. Forearm venous blood samples taken at rest and at the end of each work stage were analyzed for norepinephrine (NE), epinephrine(EPI), and lactate (LA) content. Mann-Whitney tests revealed that peak LA, NE, and EPI responses were greater in LINJ compared with HINJ subjects (LA = 7.1± 0.5 vs 3.2 ± 0.4 mM; NE = 3.1 ± 1.0 vs 0.4 ± 0.1 ng·ml-1; EPI = 0.5 ± 0.2 vs 0.1 ± 0.01 ng·ml-1). Spearman rank correlations for LINJ and HINJ groups were NE-EPI, rs= 0.85 vs rs= 0.17; NE-LA, rs= 0.83 vs rs= 0.31; and EPI-LA, rs= 0.73 vs rs= 0.41. The strong relationships between NE, EPI, and LA in the LINJ group were similar to those previously reported in able-bodied athletes. However, the relatively weak association between these factors in the HINJ group indicates that, while some function exits, the sympathoadrenal response to exercise is significantly impaired in these individuals. These results suggest that mechanisms other than catecholamines are primarily responsible for muscle lactate production during incremental exercise in individuals with HINJ.

ISSN:0195-9131    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

High-force eccentric exercise induces neuromuscular dysfunction and may augment the cardiovascular response to exercise. This investigation sought to determine whether changes in strength and sense of force following high-force eccentric exercise alter heart rate and blood pressure responses during isometric contractions. Subjects (4F,6M) performed 50 maximum resistance eccentric actions with one arm (ECC arm). Contractions at 10% of the ECC arm maximum were held for 7 min on two pre-exercise days. The force output perceived to be the same as 10% of the pre-exercise maximum was determined using a force matching task. This force, 35.6, 27.2, and 21.1% lower on days 1, 3, and 5 post-exercise, was held during isometric contractions on these days, respectively. Despite a lowering of absolute contraction force, heart rate (P< 0.05) and blood pressure (P< 0.001) responses during contractions using the ECC arm were consistently elevated relative to the control arm. However, subjects perceived that they were exerting forces similar to those achieved before eccentric exercise-induced neuromuscular dysfunction. These findings suggest that perceived effort following strength loss induced by mechanically stressful exercise dictates the cardiovascular responses during isometric contractions.

ISSN:0195-9131    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

It is well established that exercise affects immune responses in men, but little information is available for women. Whether exercise-induced immune responses are affected by circadian rhythm has not been determined. This study examined lymphocyte responses of women to exercise in the morning (AM) and evening (PM). Lymphocytes expressing markers for T, B, and natural killer (NK) cells were identified by FACScan in blood samples collected before (baseline), immediately after, and 40 min after exercise (recovery). Absolute counts of all lymphocyte subpopulations increased immediately after exercise, but at recovery values were below baseline counts. Circadian variations were noted in absolute counts for total T, helper/inducer T cells, and B cells. Although these counts were significantly higher in the PM, the magnitude of the immune response to exercise was the same in the AM and PM. In contrast, natural killer cells, both the relative counts and the magnitude of immune response were higher in the AM. Thus, it appears that despite differences in baseline cell counts the overall exercise-induced response in most lymphocyte subpopulations is similar in the AM and PM.

ISSN:0195-9131    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Decreased glutamine availability is proposed as a mechanism for changes in immune function with intense exhaustive exercise. Less is known about the immunomodulatory effects of regular nonexhaustive exercise. To determine the effects of low intensity regular exercise and dietary glutamine supplementation on plasma glutamine concentrations, lymphocyte metabolism, and immune function, male (278 ± 5 g) and female (182 ± 1 g) Sprague-Dawley Buffalo rats were fed nutritionally complete casein-based semi-purified diets ± 2% w/w glutamine. Rats were trained (21 d), as confirmed by higher (P< 0.05) succinate dehydrogenase activity in soleus muscle, to swim 2 or 4 h·d-1or remained sedentary. Exercise lowered plasma concentrations of tryptophan, glutamate, methionine, alanine, threonine, aspartate, asparagine, and ornithine and increased the lysine concentration (P< 0.05). Neither diet nor exercise altered plasma glutamine concentrations, lymphocyte phenotypes in spleen, or thein vitrorates of splenocyte energy metabolism (production of glucose and glutamine metabolites or ATP concentrations in the incubation media). Compared with nonsupplemented rats, splenic cytolytic activity (lysis of51Cr labeled YAC-1 cells) was reduced (P< 0.05) in the glutamine-supplemented exercising group. Under these conditions, glutamine supplementation does not appear to provide any added benefit to the exercise-trained animal.

ISSN:0195-9131    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

We studied gastric and intestinal function by gastric intubation/intestinal perfusion in six healthy male volunteers to evaluate optimal use of a 6% glucose-electrolyte (GES) solution. Gastric volume, residual volume, emptying rate, and secretion were measured for an initial 763 ± 19 ml gastric load of GES and at the beginning and end of four additional gastric loads (2.2 ml·kg-1; ≈180 ml) given at 10-min intervals. The relatively high gastric (713 ± 58 ml) and residual (507 ± 26 ml) volumes maintained a high gastric emptying rate (19.5 ± 1.4 ml·min-1). Composition of the GES emptied into the duodenum was also measured in this first experiment. In a second experiment, this modified solution was infused (triple lumen tube) into the duodenum at a rate equal to gastric emptying rate, or at 38 or 77% greater rates. Absorption of water(11.3-12.9 ml·h-1·cm-1) and glucose 4.3-5.6 mmol·h-1·cm-1) were similar at all perfusion rates during the second experiment. We conclude that duodenojejunal segmental absorption rates of water and glucose produced by a rapid, sustained gastric emptying rate cannot be increased by delivering a greater load of glucose and water by intestinal perfusion.

ISSN:0195-9131    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Several reports have shown that the use of oral creatine (Cr) supplementation can increase performance during brief high intensity exercise in humans. The purpose of this study was to examine the separate and combined effects of Cr supplementation and high intensity run training on the performance capacity and biochemical properties of rodent skeletal muscle. Running performance was assessed following acute (10-d) and chronic (4-wk) Cr supplementation. Results indicate that Cr supplementation alone has ergogenic effects and the combination of run training plus Cr results in a more pronounced enhancement of performance than either intervention alone. The benefits of Cr supplementation were seen most clearly during repetitive bouts of high intensity interval running. Cr concentrations increased in both the slow soleus and fast plantaris muscles (P< 0.05) in response to Cr supplementation. Increased creatine concentrations appeared to be reflected in increased phosphorylated creatine (PCr). Citrate synthase (CS) activity was increased in both the soleus and plantaris muscles following training(P< 0.05). CS activity of the untrained soleus but not the plantaris responded to the dietary stimulus. There were no significant changes in either creatine phosphokinase activity or myosin heavy chain isoform distribution following training or supplementation. These results indicate that the gains in high intensity running performance seen following Cr loading are a combined result of increased aerobic (CS) and anaerobic (Cr and PCr) energy buffering capacity of the muscle.

ISSN:0195-9131    

出版商:OVID    

年代:1997

数据来源: OVID