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PubMed1982

Metabolic and hormonal response to physical exercise during beta 1-selective and non-selective beta-blockade.

The effects of a beta 1-selective (metoprolol, 150 mg per day) and a non-selective beta-blocking agent (propranolol, 120 mg per day) on metabolic and hormonal responses to physical exercise (a 30 min bicycle ergometer test) were investigated against placebo in seven healthy male volunteers with a double blind cross-over design. The blood glucose level remained unchanged during placebo, it tended to increase during metoprolol, whereas it decreased during propranolol. Both metoprolol and propranolol counteracted the exercise-induced increase in plasma free fatty acids and caused a slight decrease in muscle glycogenolysis. The increase in blood lactate concentration during exercise was not influenced by beta-blockade. The secretion of glucagon and cortisol was not modified significantly by beta-blockade, whereas the growth hormone response to exercise was promoted equally by both beta-blocking agents. It has been assumed previously that, during treatment with beta-blocking agents, diminished hepatic gluconeogenesis, caused by the lack of lactate or free fatty acids, may result in a decline in blood glucose levels. The present results indicate that an inhibition of beta 2-mediated hepatic glycogenolysis by propranolol may also influence blood glucose homeostasis during exercise.

Adrenergic beta-Antagonists↗

PubMed1993

Plasma and cerebroventricular fluid levels of pancreatic polypeptide in the dog: effects of feeding, insulin-induced hypoglycemia, and physical exercise.

We investigated the penetration of plasma pancreatic polypeptide (PP) into the third cerebral ventricular fluid (CSF) of dogs. Plasma and CSF levels of PP were measured by RIA during the iv infusion of PP and during such stimuli as eating, insulin-induced hypoglycemia, and physical exercise. Plasma and CSF levels of insulin and glucose were also measured and compared during eating and insulin-induced hypoglycemia. Plasma glucose increased after feeding and decreased after insulin injection, followed by a corresponding change in CSF glucose without an apparent time lag. CSF insulin insignificantly increased after feeding and the injection of insulin, while CSF PP did not increase despite the marked elevation of plasma PP in response to these stimuli. CSF PP did not increase after the infusion of exogenous PP. Strenuous exercise, however, evoked an increase in both plasma and CSF PP levels; the CSF response was prompt, but more prolonged than that of plasma, suggesting the slow removal of PP from CSF. We conclude that 1) PP and insulin in CSF do not appear to play a major role in the short term regulation of food intake and acute changes in energy metabolism; and 2) PP, probably after entering the brain, may modulate brain function in such physiological situations as strenuous exercise.

Animals↗

PubMed1996

Muscular performance after a 3 month progressive physical exercise program and 9 month follow-up in subjects with low back pain. A controlled study.

The purpose of this study was to assess, in subjects with low back pain, the changes and their permanence in muscular performance after a 3 month progressive physical exercise program. Ninety subjects with chronic low back pain participated in the study. The study design was controlled and it was carried out in three groups: intensive training, home exercise, and control group. Isometric and dynamic muscle strength of the trunk and lower limb were measured, at the beginning of the study and after the 3 months exercise program, and the during each of the follow-up sessions. The Oswestry Index and back pain intensity were also determined. Both exercise groups received benefit from the progressive exercise program. Their muscular performance improved and their back pain intensity decreased significantly. Among the home exercise group, the Oswestry Index also changed positively. The results demonstrate that the home exercise program could be as effective as the intensive training program in increasing muscle strength, as well as decreasing back pain and functional disability among low back pain patients with mild functional limitations.

Adult↗

PubMed1991

[Effects of physical exercise and indobufen in patients with intermittent claudication. Results after a 2-year follow-up].

The study included 18 patients suffering from intermittent claudication before (stage 1) and after (stage 2) 3 months of rehabilitative training and after 2 years of follow-up (stage 3) during which patients undertook regular exercise (walking for 1 hour 3-4 days a week) and antiplatelet aggregating therapy with indobufen (200 mg x 2/day). A comparison of the data revealed that:a) there was a significant and gradual increase in the claudication pain distance (CPD) and maximal walking distance (MWD), and a reduced recovery time between stages 1 and 3 (parameters were assessed during and after walking on a treadmill (rolling mat) at a speed of 3.2 Km/h on a 12% slope); b) the resting ankle/arm pressure ratio was unchanged, but a significant increase was observed when the ratio was measured after exercise between stages 1 and 3; c) fibrinogenemia was significantly reduced between stages 1 and 2. Out of 18 subjects studied, 8 exceeded an MWD of 640 metres (maximum limit of exercise test which was suspended after 12'), 3 became asymptomatic, and 1 showed a significantly reduced capacity to walk. The paper concludes that, although it is necessary to obtain a confirmation from controlled studies, indobufen therapy and regular physical exercise represent an efficacious therapeutic approach, even over a long-term period, to stage II chronic arteriopathies of the lower limbs.

Aged↗

PubMed2002

Regular physical exercise improves endothelial function in heart transplant recipients.

BACKGROUND: Impaired endothelial function is detectable in heart transplant (HTX) recipients and regarded as risk factor for coronary artery disease. We have studied whether endothelial function can be improved in HTX patients participating in a regular physical training program as demonstrated in patients with chronic heart failure, hypertension and coronary artery disease. METHODS: Male HTX patients and healthy, age-matched controls were studied. Seven HTX patients (age: 60 +/- 6 yr; 6 +/- 2 yr of HTX) participated in an outpatient training program, six HTX patients (age: 63 +/- 8 yr; 7 +/- 1 yr of HTX) maintained a sedentary lifestyle without regular physical exercise since transplantation. A healthy control group comprised six subjects (age: 62 +/- 6 yr). Vascular function was assessed by flow-mediated dilation of the brachial artery (FMD). Systemic haemodynamic responses to intravenous infusion of the endothelium independent vasodilator sodium nitroprusside (SNP) and to NG-monomethyl-L-arginine (L-NMMA), an inhibitor of constitutive nitric oxide synthase, were also measured. RESULTS: Resting heart rate was significantly lower (p < 0.05) in healthy controls (66 +/- 13) than in the HTX training group (83 +/- 11) and in non-training HTX patients (91 +/- 9), baseline blood pressure also tended to be lower in healthy subjects and in the training HTX patients. FMD was significantly higher (p < 0.05) in the control group (8.4 +/- 2.2%) and in the training group (7.1 +/- 2.4%), compared with non-training HTX patients (1.4 +/- 0.8%). The response of systolic blood pressure (p = 0.08) and heart rate (p < 0.05) to L-NMMA was reduced in sedentary HTX patients compared with healthy controls and heart rate response to SNP was also impaired in sedentary HTX patients. DISCUSSION: Regular aerobic physical training restores vascular function in HTX patients, who are at considerable risk for developing vascular complications. This effect is demonstrable in conduit and systemic resistance arteries.

Blood Pressure↗

PubMed1984

Bidirectional alteration of insulin receptor affinity by different forms of physical exercise.

Insulin binding of monocytes and erythrocytes was studied in untrained male volunteers after 15 min of exhaustive bicycle exercise (EE) and several days later after moderate exercise (ME) for 90 min. Insulin receptor affinity decreased after EE in monocytes (26.4% decrease; P less than 0.01) and in erythrocytes (10.4%; P less than 0.05) with no change in receptor number. After ME, however, binding to monocytes was enhanced by 15.2% (P less than 0.05) due to increased receptor affinity. The number of circulating monocytes was markedly increased after both forms of exercise, averaging 105% after EE and 57% after ME. The bidirectional effect on monocyte insulin binding could be reproduced in vitro by incubation of preexercise cells with post-exercise serum: 12.4% (P less than 0.05) decrease with EE serum and 6.1% (P less than 0.05) increase with ME serum. The effect was prevented by overnight dialysis. These results suggest that physical exercise not only entails adjustment of serum insulin but also of cellular hormone sensitivity, presumably through the mediation of low-molecular-weight serum components.

Adult↗

PubMed2002

Serum GH response to pharmacological stimuli and physical exercise in two siblings with two new inactivating mutations in the GH-releasing hormone receptor gene.

OBJECTIVE: Inactivating mutations of the GH-releasing hormone receptor (GHRHR) gene (GHRHR) cause familial isolated GH deficiency (IGHD) type IB. The GH response to physical exercise (PE) in patients lacking GHRHR has never been studied. We hypothesized that subjects lacking functional GHRHR may be a model to study GH response to PE. DESIGN: We have analyzed peripheral genomic DNA of a family with two sibs affected by IGHD IB for mutations in the GHRHR, studied the patients' GH response to different GH secretagogues and to PE, and examined the morphology of their pituitary gland by magnetic resonance imaging (MRI). METHODS: The GHRHR was analyzed by direct sequencing of the 13 exons, intron-exon boundaries, and of the proximal 327 bp of the promoter region in the index case. The patients' GH response to GHRH and standardized PE was studied twice, using a GH ultrasensitive assay in the second round of testing. RESULTS: Both subjects were compound heterozygotes for two previously undescribed mutations in the GHRHR that are predicted to cause complete lack of functional GHRHR protein: a nonsense mutation in codon 43 (Q43X), and a splice mutation at the beginning of intron 3 (IVS3+1G-->A). MRI showed hypoplasia of their anterior pituitaries. Both subjects had a small but detectable increase in serum GH after maximal PE. CONCLUSIONS: GHRHR mutations need to be considered in IGHD IB patients even in the absence of parental consanguinity, and patients lacking GHRHR may provide a model to study the mechanism by which PE influences GH secretion.

Base Sequence↗

PubMed2000

[Nutrition and physical exercise].

The principles of a good diet and proper nutrition are the same for people practising sports and for non-athletes. The main difference lies in the amount of energy that sportsmen and women need to carry out a more intense physical activity and to keep an appropriate weight to allow greater performance. The relationship between nutrition and physical exercise has often been shrouded in confusion and conjecture, so certain products or supplements turn into real myths through attempts to achieve better athletic results, despite the fact the information available on the true effect of a particular substance or food on athletic performance is, quite limited and disputed. This paper attempts to clarify the scientific information available on this subject.

Carbohydrate Metabolism↗

PubMed1989

A method for the retrospective estimation of the individual respiratory intake of a highly and a poorly metabolising solvent during rest and physical exercise.

A method for the retrospective estimation of the individual respiratory intake was tested. The method is based on system dynamics. Subjects were exposed simultaneously to the poorly metabolising solvent tetrachloroethene (PER, perchloroethylene) and the highly metabolising trichloroethene (TRI) at rest, 30, and 65 watt physical exercise. The time courses of the alveolar concentration (Calv) of both PER and TRI were measured. A retrospective estimation of the individual intake of PER could be carried out up to 400 hours after exposure with 10-20% accuracy, irrespective of the level of exercise. The estimates of the intake of TRI are less accurate. The Calv in the 1-15 hours postexposure permits the estimation of the intake of TRI within a mean error of 25% for most subjects. For men the method may be applied up to 48 hours after exposure within 20% error. For women the intake estimates showed a poor accuracy with the use of Calv beyond the day of exposure.

Adult↗

PubMed2006

Hysteresis of electrocardiographic depolarization-repolarization intervals during dynamic physical exercise and subsequent recovery.

The post-exercise electrocardiographic QT interval is shortened relative to that at similar heart rates during exercise or pre-exercise rest. This lag in QT adaptation to the recovering heart rate is described as "hysteresis". No previous studies have quantified the influence of ECG electrode placement on hysteresis following physical exercise. Six males and six females of similar age, mass and aerobic fitness undertook progressive sub-maximal bicycle exercise. A three-channel ECG was recorded continuously during pre-exercise, exercise and recovery. Beat-to-beat NN (cardiac interval) and QT(a) interval (Q wave onset to T wave apex) data were measured for each sinus heart beat. QT(a)-NN hysteresis was calculated as the difference in QT(a) magnitude at identical heart rates during the rest/exercise and post-exercise recovery periods. There were some significant (p < 0.05) between-channel and between-gender differences in calculated hysteresis values. Hysteresis was generally greatest during the second or third minute post-exercise; ranges of means for all channels were 10.9 +/- 11.7 ms to 25.5 +/- 16.8 ms (males) and 19.1 +/- 10.3 ms to 28.4 +/- 3.0 ms (females). For males only, hysteresis values calculated using channel 1 between 1 and 3 min post-exercise were generally significantly (p < 0.05) different to those between 4 and 10 min. Similar trends were observed in females. QT(a)-NN hysteresis is significantly affected by the locations of the ECG electrodes used to record the surface ECG. These results emphasize the need for standardization of ECG electrode placement in future investigations.

Adolescent↗

PubMed1977

Effect of physical exercise on erythrocyte lipids, biliary cholesterol and bile lithogenicity in rats.

Male Wistar rats were exercised (E) by daily 1 h swimming for 24 days. Sedentry controls (S) were caged individually. Bile analysis at the end of the experiment (24 h after the last exercise) showed a decrease in bile cholesterol (CH) (P less than 0.02) and phospholipids (PL) (P less than 0.01) in the exercising animals, but no significant change in the bile acids (BA). These changes in the exercising rats resulted in a decreased CH saturation of bile: in an improvement in the (BA + PL)/CH ratio (P=0.05) and a trend to a decrease in the per cent saturation of bile CH. Exercise did not affect the bile flow or bile acid flux rate. Exercise decreased erythrocyte phospholipids (P less than 0.01). The effect of exercise on bile was associated with a trend to lower CH in the erythrocytes and in the adipose tissue and thus most likely does not represent a shift of cholesterol from the liver to the peripheral tissues. Physical exercise may be a preventive factor in cholesterol gallstone formation.

Adipose Tissue↗

PubMed1998

Evaluation of a bone's in vivo 24-hour loading history for physical exercise compared with background loading.

The present study sought to answer two research questions. First, how distinctive, as a potential osteogenic stimulus, are short-duration bouts of treadmill exercise relative to sedentary background activity? Second, how well does daily effective strain stimulus relate the loading history for one such exercise program, in comparison with other experimental loading programs, to bone formation? In vivo cortical strains were measured in the tibiotarsus of White Leghorn chickens at a late stage of skeletal growth (14-34 weeks old) under the conditions of a previous investigation of bone formation in response to an exercise program (15 min/day, treadmill gait at 60% maximum speed while carrying 20% body mass) that included sedentary background activity. These strain data were compiled into 24-hour loading histories of peak cyclic strain, demonstrating that strains were statistically different for exercise and background activities (p < 0.0001), with both the magnitude and number of cyclic strain events being greater during exercise (generally greater than 500 microstrain, 2,500 cycles/day) than during background activity (generally less than 500 microstrain, mean: 775 cycles/day). Strains during exercise accounted for more than 97% of the daily effective strain stimulus for bone adaptation, despite the fact that exercise comprised only 1% of the daily period (15 min/day). The levels of the daily effective strain stimulus were similar to those calculated for strains engendered by artificial loading of functionally isolated avian ulnae, which either maintained bone mass or resulted in a 15% increase of cortical cross-sectional area in both sets of studies. These results indicate that short-duration bouts of treadmill exercise and sedentary background activity can represent distinct osteogenic stimuli for adaptive bone modeling. They also provide experimental support for the use of a daily effective strain stimulus to quantify skeletal loading histories for differing programs of physical exercise, although the relative importance of other mechanical and nonmechanical factors requires further investigation.

Animals↗

PubMed1998

Self-management of fibromyalgia: the role of formal coping skills training and physical exercise training programs.

There has been growing interest in the use of formal self-management training programs for people with fibromyalgia (FM). In these programs, health care professionals serve as trainers and provide education about FM and guided instruction in specific self-management strategies. A review of the literature on formal self-management training programs for FM suggests that they can be divided into groups: 1) those emphasizing training in coping skills (e.g., relaxation, activity pacing, and problem-solving techniques), and 2) those emphasizing training in physical exercise (e.g., cardiovascular fitness, strength, and endurance training). In this article, we review studies that have tested the efficacy of both types of programs. In addition, we identify key individual and contextual variables that are related to outcome and highlight future directions in the research and development of self-management programs.

Adaptation, Psychological↗

PubMed2004

Chronic physical exercise reduces anxiety-like behavior in rats.

While many individuals with anxiety disorders receive drug therapy, many do not respond or adversely respond to drugs. An alternative treatment, exercise, has been shown to relieve negative feelings and induce positive shifts in mood. The purpose of this study was to establish an animal model to specifically test the effects of chronic physical exercise on anxiety-related behaviors. Thirty-two male Sprague Dawley rats were divided into two groups: runners (R) and nonrunners (NR). Runners ran on a treadmill for 45 minutes a day, five days a week, for ten weeks at a moderate intensity. Nonrunners remained in their cages in the treadmill room during the running period and were handled for an equal amount of time. After ten weeks of training, two behavioral tests were administered including the elevated plus maze and open field tests. Results comparing R and NR showed higher responses by R in percent open arm time and center square time during the elevated plus maze test, as well as in number of entries into the center, number of rears, and lower fecal boli count during the open field test, p < 0.05. In addition, there were no differences in total activity levels between groups as indicated by similar closed arm entries in the elevated plus maze test and total lines crossed in the open field test. These results indicate that treadmill training reduces anxiety-like behaviors in two animal tests of anxiety, without a significant change in total activity levels. These data are in support of treadmill training as a model to test the anxiolytic effects of exercise.

Animals↗

PubMed1978

Effect of physical exercise on the activity of GOT isozyme in human plasma.

Untrained healthy male volunteers were subjected to the study on the effects of exercise (bicycle ergometer, 920 kpm/min for 30 min) upon GOT isozyme (supernatant GOT, s-GOT and mitochondrial GOT, m-GOT) activities in plasma. Significant increases in the levels of both s-GOT and m-GOT activity were observed after the exercise (p less than 0.001). After 30 min of rest m-GOT activity almost returned to its preexercise value. However, s-GOT activity did not return to its preexercise activity. The changes in the activity of GOT isozyme after physical exercise are discussed.

Adolescent↗

PubMed2000

Effect of dietary supplements and physical exercise on sensory perception, appetite, dietary intake and body weight in frail elderly subjects.

This present study investigated the effect of a 17-week intervention programme with nutrient-dense foods (enriched with vitamins and minerals at 25-100% of the Dutch recommended dietary allowance) and/or physical exercise in 159 frail elderly subjects (forty-six men, 113 women, mean age 78.7 (SD 5.6) years). Subjects were randomized into four groups: (1) control, (2) nutrition intervention, (3) exercise or (4) both nutrition intervention and exercise. Main outcome variables were sensory perception (smell test and questionnaire), appetite (questionnaire), energy intake (3 d food record) and body weight (on a weighing scale and with dual energy X-ray absorptiometry measurements). At baseline, moderate but significant correlations were found between appetite and energy intake (r 0.30, P < 0.0001), between smell test and smell perception assessed by questionnaire (r 0.40, P < 0.0001) and between lean body weight and energy intake (r 0.50, P < 0.0001). Results after 17-weeks intervention revealed neither change in smell test scores (P = 0.19) nor in appetite (P = 0.17). A slight positive effect of exercise compared with non-exercising groups on energy intake (difference 0.5 MJ, P = 0.05) was shown next to a preserving effect of exercise on lean body mass (+0.08 kg) compared with a decrease (-0.4 kg) in non-exercisers (P < 0.02). The correlation between the change in lean body mass and change in energy intake was 0.18 (P = 0.05). In conclusion, an interesting preserving effect on lean body mass in frail elderly subjects due to 17 weeks of exercise was shown. Since a decline in lean body mass was observed in the non-exercisers, effects may be attributable to change in activity pattern. Changes in lean mass were also slightly, but significantly, correlated with changes in energy intake. In turn, energy intake was not related to a change in reported appetite or sensory perception. Nutrient-dense foods were not able to improve any of the outcome variables in this study.

Aged↗

PubMed2005

Ouabain-like compound changes rapidly on physical exercise in humans and dogs: effects of beta-blockade and angiotensin-converting enzyme inhibition.

Ouabain, an inhibitor of the sodium pump, has been identified as a constituent of bovine adrenal glands. We were interested whether the release of this cardiotonic steroid is stimulated by physical exercise. Hence, athletes and healthy dogs were subjected to ergometry. Ouabain-like compound (OLC) was measured in venous blood by enzyme-linked immunosorbent assay as well as by (86)Rb+ uptake inhibition (as ouabain equivalents). OLC increased in venous blood of athletes after 15 minutes of ergometry from 2.5+/-0.5 to 86.0+/-27.2 nmol/L (n=51; P<0.001), as did the concentration of a circulating inhibitor of the sodium pump from 7.3+/-1.7 to 129.8+/-51 nmol/L (ouabain equivalents, P<0.05). Half-maximal increase in heart rate and systolic blood pressure occurred at 5.1+/-1.2 nmol/L and at 30+/-1 nmol/L OLC, respectively. On rest, OLC decreased in humans and dogs with a half-life of 3 to 5 minutes. In beagles exposed to moderate exercise on a treadmill for 13 minutes, levels of OLC increased 46-fold (from 3.7+/-0.8 to 166.9+/-91.8 nmol/L; n=6; P<0.005). This effect was suppressed when the dogs had been treated for 3 weeks with the beta1-adrenergic receptor blocker atenolol or the angiotensin-converting enzyme inhibitor benazepril. We conclude that OLC changes rapidly during exercise and is under the control of norepinephrine and angiotensin II.

Adrenergic beta-Antagonists↗

PubMed1989

Differential effect of physical exercise routines on ventricular myosin and peripheral catecholamine stores in normotensive and spontaneously hypertensive rats.

The influence of the adrenergic system on the population of ventricular myosin isoenzymes under physiological conditions was assessed by subjection of normotensive and spontaneously hypertensive rats (SHR) to different types of physical exercise that increased the activity of the peripheral adrenergic system to varying degrees. The routines, which were 5-6 weeks in duration, involved the mild exercise of enforced swimming (2 x 90 min/day), spontaneous running (daily, about 15 km/10-12 hr) that resulted in absolute ventricular hypertrophy, and enforced running of low intensity (daily, 2 x 1.8 km/3 hr) but associated with marked stressors. Swimming and spontaneous running reduced the high blood pressure of SHR, whereas enforced running increased it. In both strains, the myosin isoenzymes were redistributed in the direction of V1 after swimming but not after running. In SHR, therefore, reduction of pressure load seems insufficient for induction of a higher proportion of V1. The unique and, until now, unexplained effect of swimming was attributed to the pronounced activation of the peripheral adrenergic system as judged from catecholamine stores of ventricles and adrenal glands. Only swimming increased the norepinephrine content of ventricles and adrenal glands in normotensive rats. Swimming also had the strongest influence in SHR. Further evidence for the influence of the adrenergic system came from the effect of selective cardiac beta-blockade with atenolol (50 mg/kg/day). The diminished adrenergic drive of the heart reduced the proportion of V1 to a greater extent in the swimming rats than in the sedentary rats. Taken together, the data demonstrate that substantial changes in adrenergic activity occur under physiological conditions associated with an altered myosin heavy-chain expression.

Animals↗