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PubMed1998

Long-term physical exercise and quantitatively assessed human coronary collateral circulation.

OBJECTIVES: This prospective, cross-sectional study sought to determine an association between the level of long-term physical activity as well as other clinical and angiographic variables and an index of collateral flow to the vascular region undergoing percutaneous transluminal coronary angioplasty (PTCA). BACKGROUND: There is limited and conflicting information about the effect of physical exercise on the coronary collateral circulation in humans, partly because previous studies lacked a quantitative means of assessing collateral channels. METHODS: In 79 patients (mean [+/-SD] age 58 +/- 10 years) with coronary artery disease undergoing PTCA (no transmural myocardial infarction), a coronary collateral flow index was determined as the ratio between the intracoronary (IC) distal flow velocity time integral during (Vi(occl)[cm]) and after (Vi(occl) [cm]) PTCA of the stenosis. Vi(occl)/Vi(occl) was measured by a 0.014-in. Doppler guide wire, from which an IC electrocardiogram (ECG) was also recorded. Patients without ECG ST-T wave changes during PTCA were considered to have sufficient collateral channels (n = 29); those with ST-T wave changes were considered to have insufficient collateral channels (n = 50). The level of long-term physical activity was determined by a structured interview (score from 1 to 4). Univariate and multivariate analyses were used to find associations between physical activity as well as 30 other clinical and angiographic variables and the collateral flow index. RESULTS: Long-term physical activity during leisure time, but not during work hours, and the severity of the stenosis undergoing PTCA were found to be independently and directly associated with sufficient versus insufficient collateral channels and with Vi(occl) Vi(occl) (leisure time physical activity [LTPA] score 3.3 +/- 0.9 vs. 2.4 +/- 1.0, p = 0.0002; percent diameter stenosis 88 +/- 12% vs. 80 +/- 14%, p = 0.001; Vi(occl)/Vi(occl) = 0.1 +/- 0.1 LTPA score, p = 0.0002 for trend). CONCLUSIONS: In patients with coronary artery disease, the level of long-term physical activity during leisure time and the severity of the stenosis undergoing PTCA are directly associated with the quantitative degree of collateral flow.

Adult↗

PubMed1998

[Rehabilitation by physical exercise in chronic heart failure].

The aim of rehabilitation is to improve exercise capacity and, thereby, the autonomy of patients with cardiac failure. For many years, these patients were considered inapt to perform physical exercise and they are in the same situation at the dawn of the year 2000 as patients with myocardial infarction forty years ago. The symptoms of cardiac failure (dyspnoea of effort and muscular fatigue) are not only the consequence of pulmonary hypertension and decreased muscular perfusion. Prolonged interruption of exercise and long stays in bed or in a chair lead to anatomical and functional amyotrophy, which, in turns, incites to further inactivity. Deconditioned respiratory muscles cannot tolerate the increased load of hyperventilation. Neurohormonal changes cause vasoconstriction which reduces muscular perfusion. Physical training can significantly improve these abnormalities, though it does not seem to have a measurable effect on cardiac function; based on segmental work which enables performance of substantial efforts with a minimum of haemodynamic changes, it provides a 20 to 30% gain in capacity, mainly increasing the duration of submaximal exercise rather than maximum performance. Muscular fatigue is the symptom which is the most improved. Unfortunately the organisation, which is more difficult than in the post-infarction period, and the generalisation of the practice of long-term, well adapted physical training remains marginal although hundreds of thousands of patients could benefit; more than the inertia of the official instances concerning anything related to cardiac rehabilitation, it is the lack of interest shown by cardiologists and the absence of flexible structures within the health care organisation for elderly people which are responsible.

Aged↗

PubMed1990

Does physical exercise influence the frequency of postmenopausal hot flushes?

The frequency of moderate and severe hot flushes was investigated in a group of women (n = 142) who took part in organized physical exercise on a regular basis, and a control group of all women 52 and 54 years old in the city of Linköping, Sweden (n = 1,246). Only women with natural menopause and without a history of hormonal replacement treatment were statistically compared in the study. It appeared that moderate and severe vegetative symptoms with hot flushes and sweatings were only half as common among the physically active postmenopausal women (21.5%) as in the control group (43.8%). Although this could be due to a positive selection of these physically active women, it might also be due to the fact that exercise may affect the mechanisms that elicit hot flushes in peri- and postmenopausal women.

Climacteric↗

PubMed1995

Impact of intensive physical exercise and low-fat diet on collateral vessel formation in stable angina pectoris and angiographically confirmed coronary artery disease.

This randomized study was performed to assess the effects of > 3 hours of physical exercise per week and low-fat diet on collateral formation in nonselected patients with coronary artery disease (intervention group, n = 56). Results were compared with those of patients in a control group (n = 57), who received usual care by their private physicians. Coronary lesions were assessed by quantitative coronary angiography at the beginning and after 1 year of study (n = 92). As previously reported, after 1 year there was a significant retardation of progression of coronary artery disease in the intervention group as compared with the control group. In this study, evaluation of collateral formation revealed no significant difference between both groups, and changes in hemodynamic and metabolic variables or leisure time physical activity were not related to changes in collateral formation. Although progression of the disease was significantly related to an increase in collateral formation, regression was significantly related to a decrease in collateral formation (p < 0.00001). Because patients in the intervention group exercised for > 3 hours/week, and patients with regression of coronary artery disease even dedicated 5 to 6 hours to leisure time physical activity per week, these findings question whether an exercise program within the safety tolerance of patients will be able to induce coronary collateralization in the presence of regression of coronary artery disease.

Activities of Daily Living↗

PubMedDate not supplied

[Androgen regulation of the level of tissue-specific proteins in skeletal muscles during physical exercise].

Administration of testosterone after exercises led to suppression of the hormone production during the anabolic phase within 72-120 hrs of muscles adaptation to physical loading. Content of the androgen receptors was also altered. The supercompensatory phase in content of proteins (myoglobin and aspartate aminotransferase as index) was absent due to an impairing effect of testosterone on muscle adaptation. These data suggest that administration of testosterone could not serve as an adequate model of a body androgenization which was observed in anabolic phase of muscle adaptation to physical exercises.

Androgens↗

PubMed1989

Trait anxiety, submaximal physical exercise and blood androgens.

This study evaluates the relationship between trait anxiety and both androgen and gonadotrophic hormone levels at rest and during severe physical exercise. Twelve volunteers were selected among 160 untrained male collegial students and classified as anxious (N = 6) or non-anxious (N = 6) subjects according to their scores on three trait-anxiety tests (STAI, IPAT, 16 PF). Serum delta 4-androgen (testosterone and delta 4-androstenedione), delta 5-androgen (DHEA and DHEA-SO4) and gonadotrophin (LH and FSH) concentrations were measured by radioimmunoassay before, during and after 20 minutes of intensive bicycle exercise (80% of maximal heart rate). Results indicate significantly lower serum delta 4-androgens in anxious subjects before exercise. However, for each subject and irrespective of his anxiety level, all measured serum androgen concentrations increased significantly during exercise, although delta 4-androstene-dione remained lower in anxious subjects than in non-anxious ones. Serum LH concentrations (but not FSH) were significantly higher in anxious subjects throughout the observation periods. However, exercise induced in each subject a significant decrease in the serum level of both gonadotrophic hormones. The results suggest that trait anxiety level may constitute an important factor that affects both pre-exercise and exercise serum androgen concentrations in untrained subjects.

Adult↗

PubMed1997

Does physical exercise influence the occurrence of epileptiform EEG discharges in children?

PURPOSE: To determine if, and how, epileptiform EEG discharges in children were influenced by physical exercise. METHODS: Twenty-six children with intractable partial and generalized epilepsy exercised during video-telemetry recording, aiming at exhaustion after approximately 10 min. RESULTS: During the exercise, epileptiform discharges decreased in 20 of 26 children (17 children had at least 25% reduction) and showed a rebound increase after the exercise (17 of 26 children) compared to baseline conditions. This exercise-induced reduction in epileptiform discharges reached statistical significance only in the 16 patients with localization-related epilepsy. Five patients showed an atypical EEG response to exercise with either unchanged or increased epileptiform activity while exercising. As compared to the other patients, these 5 children had experienced frequent clinical seizures during or immediately after exercise in their leisure time. CONCLUSIONS: In the majority of the tested children, epileptiform EEG discharges decreased during exercise. "Exercise-EEG" may be a helpful diagnostic tool to identify patients who are disposed to have exercise-induced seizures.

Adolescent↗

PubMed1991

Respiratory muscle fatigue limiting physical exercise?

Inspiratory muscle fatigue has been documented during loaded breathing or acute respiratory failure, but its role in exercise limitation is still undetermined. Electromyographic (EMG) signs of diaphragmatic fatigue develop in normal subjects hyperventilating above 70% of maximal voluntary ventilation (MVV), a ventilatory level commonly attained at peak exercise. EMG signs of diaphragmatic fatigue also occur during high power cycling exercise in normal subjects and chronic obstructive pulmonary disease (COPD) patients. However, a loss of respiratory muscle strength has rarely been documented following strenuous physical exercise with techniques independent of the subjects' collaboration. Prior inspiratory muscle fatigue decreases exercise tolerance in normal subjects but its effect is largely unknown in COPD patients. Respiratory muscle rest by negative pressure ventilation was reported to improve exercise tolerance in COPD, but this beneficial effect was not confirmed by controlled studies. The effect of inspiratory muscle training on exercise tolerance is still undefined by existing data, in part because of differences in methods and selection criteria between studies. Although respiratory muscle fatigue may occur during exercise, it is not clearly established whether interventions directed at respiratory muscles may improve exercise tolerance in COPD.

Electromyography↗

PubMed1999

Performance of the [13C]-acetate gastric emptying breath test during physical exercise.

BACKGROUND: The gastric emptying rate of liquids can be determined non-invasively using the [13C]-acetate breath test at rest. The aims of our study were to validate this test during physical exercise against the double-sampling method and to evaluate the time needed for intestinal absorption and the delay between absorption and appearance of 13CO2 in breath, both at rest and during exercise. DESIGN: Fifteen well-trained male subjects were investigated. Gastric emptying was determined simultaneously measuring the 13CO2 breath enrichment after intragastric administration of 0.5 L of carbohydrate solution with 150 mg of [13C]-acetate added and by the double-sampling technique (n = 9). In separate tests, 150 mg of [13C]-acetate was also applied intraduodenally and intravenously (n = 6), both at rest and during exercise. Time-to-peak (TTP) 13CO2 enrichment was determined using a curve fit and was considered as the parameter for gastric emptying. RESULTS: TTP enrichment derived from the breath test significantly correlated with the gastric emptying half-time obtained from the gastric aspirates. During exercise, median TTP enrichment values after intragastric, intraduodenal (i.d.) and intravenous (i.v.) administration of [13C]-acetate were 22.3, 10.3 and 5.4 min respectively. During exercise, i.d. and i.v. values were reached significantly earlier than at rest. CONCLUSION: The [13C]-acetate breath test can be used as a non-invasive method to determine relative gastric emptying rates of liquids during exercise, but the results are influenced by the rate of absorption and the time needed for subsequent oxidation of [13C]-acetate and exhalation of 13CO2.

Acetates↗

PubMed1992

[Testing of arterial hypertension with physical exercise PWCx ].

The relation of physical fitness (PF) to blood pressure (BP) and arterial hypertension risk factors was studied in a representative sample by PWCX exercise testing. The relations were studied at the initial stage, during exercise and recovery by using the multivariance stepwise regression analysis. This complex approach allowed the independent relation of PF to BP to be found. In normotensive males, systolic BP determined 4% PF variability after the first exercise, while in hypertensive males, the second exercise heart rate and age determined 27 and 9% PF variability, respectively. In normotensive females, the first exercise heart rate determined 62% PF variability, in hypertensive females, the second exercise systolic BP and age determined 4 and 2% PF variability, respectively. The value x shows the relation of PF to heart rate and BP in the restorative period and is an additional significant parameter of PF and the functional status of the cardiovascular system.

Adult↗

PubMed1990

Physical exercise and menstrual cycle alterations. What are the mechanisms?

The prevalence of menstrual cycle alterations in athletes is considerably higher than in sedentary controls. There appears to be a multicausal aetiology, which makes it extremely difficult to dissociate the effects of physical exercise on the menstrual cycle from the other predisposing factors. From cross-sectional studies it appeared that physical training eventually might lead to shortening of the luteal phase and secondary amenorrhoea. Prospective studies in both trained and previously untrained women have shown that the amount and/or the intensity of exercise has to exceed a certain limit in order to elicit this phenomenon. We hypothesise, therefore, that apart from a certain predisposition, athletes with a training-induced altered menstrual cycle are overreached (short term overtraining, which is reversible in days to weeks after training reduction). Menstrual cycle alterations are most likely caused by subtle changes in the episodic secretion pattern of luteinising hormone (LH) as have been found in sedentary women with hypothalamic amenorrhoea as well as in athletes after very demanding training. The altered LH secretion then, might be caused by an increased corticotrophin-releasing hormone (CRH) secretion which inhibits the gonadotrophin-releasing hormone (GnRH) release. In addition, increased CRH tone will lead to increased beta-endorphin levels which will also inhibit the GnRH signaller. Finally, the continuous activation of the adrenals will result in a higher catecholamine production, which may be converted to catecholestrogens. These compounds are known to be potent inhibitors of GnRH secretion. In conclusion, menstrual cycle alterations are likely to occur after very demanding training, which causes an increase secretion of antireproductive hormones. These hormones can inhibit the normal pulsatile secretion pattern of the gonadotrophins.

Amenorrhea↗

PubMed2002

['Survival of the fittest': effect of regular physical exercise on health and life expectancy].

According to the 'Australian burden of disease study', physical inactivity appears to be a leading risk factor in the population at large, accounting for no less than 6.7% of the total loss of disability-adjusted life years. In women it is even the most important risk factor. Regular physical mobility and exercise can reduce this negative influence. The effects are: improvement of cardiovascular fitness, prevention of coronary events, and the reduction of excess mortality. The mortality risk may be reduced by 47% by physical activity, depending on the energy expenditure. Especially the studies of the last two years have so convincingly proven a robust effect of daily physical exercise that on this point permissiveness is no longer acceptable in the advice to the population at large.

Cardiovascular Diseases↗

PubMed1991

Evidence that the effect of physical exercise on NK cell activity is mediated by epinephrine.

The present study was designed to test the hypothesis that the changes in natural killer (NK) cell activity in response to physical exercise were mediated by increased epinephrine concentrations. Eight healthy volunteers 1) exercised on a bicycle ergometer (60 min, 75% of maximal O2 uptake) and 2) on a later day were given epinephrine as an intravenous infusion to obtain plasma epinephrine concentrations comparable with those seen during exercise. Blood samples were collected in the basal state, during the last minutes of exercise or epinephrine infusion, and 2 h later. The NK cell activity (lysis/fixed number of mononuclear cells) increased during exercise and epinephrine infusion and dropped below basal levels 2 h afterward. The increased NK cell activity during exercise and the epinephrine infusion resulted from an increased concentration of NK (CD16+) cells in the peripheral blood. On the other hand, the decreased NK cell activity demonstrated 2 h after exercise and epinephrine infusion did not simply reflect preferential removal of NK cells from the blood, because the proportion of CD16+ cells was normalized. On the basis of the finding that indomethacin abolished the suppressed NK cell activity in vitro and the demonstration of a twofold increase in the proportion of monocytes (CD14+ cells) 2 h after exercise and epinephrine infusion, we suggest that, after stress, prostaglandins released by monocytes are responsible for downregulation of NK cell function. Our findings support the hypothesis that increased plasma epinephrine during physical stress causes a redistribution of mononuclear subpopulations that results in altered function of NK cells.

Adult↗

PubMed1991

Altered sympathetic control of nutrient mobilization during physical exercise after lesions in the VMH.

To study the impact of obesity on sympathetic nervous regulation of nutrient mobilization, obese rats and lean controls were subjected to physical exercise. Male Wistar rats, rendered obese by bilateral electrolytic lesions of the ventromedial hypothalamus (VMH) were subjected to 15 min swimming. Permanent cardiac catheters allowed frequent blood sampling. At rest, glucose, free fatty acids (FFA), and insulin concentrations were elevated in the obese animals, whereas catecholamine levels were similar in both groups. During exercise, glucose concentrations reached higher values in the lesioned rats, whereas these animals did not display the normal FFA increment. Plasma insulin concentrations were suppressed in both groups, and the rate of suppression was very similar when expressed as percentage change from resting levels. There was no difference in plasma epinephrine responses during swimming, but the increase in norepinephrine was diminished in the obese animals. The results suggest that obesity after VMH lesion leads to reduced stimulation of lipolysis by norepinephrine and a predominant mobilization of glucose during exercise, both favoring glucose utilization and the accumulation of fat.

Animals↗

PubMed2000

The effects of physical exercise on the concentrations of ferritin and transferrin receptor in plasma of female judoists.

The aim of the study was to assess the effect of physical exercise on the changes in concentrations of ferritin and soluble transferrin receptor (sTfR) in plasma in course of 10 consecutive days of a training camp. Ten female elite judoists, aged 17-23 years, participated in the study. Mean concentration of ferritin for the 10 day period was 62.8 x 1.633(+/-1) microg/l, the within-subject, day-to-day variability being very high (13-75%). Ferritin concentrations were significantly correlated with the training load on the preceding day (r = 0.397; p < 0.001). Mean level of sTfR was 2.56 x 1.291(+/-1) mg/l and its within-subject variability was much lower (4-16%). Although the training loads had an effect on the intravascular hemolysis as indicated by a significant, negative correlation between load scores and haptoglobin concentration (r = -0.282; p < 0.01), the latter was not correlated significantly with sTfR levels. It was concluded that the soluble transferrin receptor is a more stable indicator of iron status under high training loads since, unlike ferritin, it does not respond to the workload on the preceding day. Moreover, the intravascular hemolysis observed in athletes does not affect the sTfR levels in plasma.

Adolescent↗

PubMed1993

Autonomic control of heart rate during physical exercise and fractal dimension of heart rate variability.

The objectives of the present study were to investigate autonomic nervous system influence on heart rate during physical exercise and to examine the relationship between the fractal component in heart rate variability (HRV) and the system's response. Ten subjects performed incremental exercise on a cycle ergometer, consisting of a 5-min warm-up period followed by a ramp protocol, with work rate increasing at a rate of 2.0 W/min until exhaustion. During exercise, alveolar gas exchange, plasma norepinephrine (NE) and epinephrine (E) responses, and beat-to-beat HRV were monitored. HRV data were analyzed by "coarse-graining spectral analysis" (Y. Yamamoto and R. L. Hughson. J. Appl. Physiol. 71: 1143-1150, 1991) to break down their total power (Pt) into harmonic and nonharmonic (fractal) components. The harmonic component was further divided into low-frequency (0.0-0.15 Hz) and high-frequency (0.15-0.8 Hz) components, from which low-frequency and high-frequency power (Pl and Ph, respectively) were calculated. Parasympathetic (PNS) and sympathetic (SNS) nervous system activity indicators were evaluated by Ph/Pt and Pl/Ph, respectively. From the fractal component, the fractal dimension (DF) and the spectral exponent (beta) were calculated. The PNS indicator decreased significantly (P < 0.05) when exercise intensity exceeded 50% of peak oxygen uptake (VO2 peak). Conversely, the SNS indicator initially increased at 50-60% VO2peak (P < 0.05) and further increased significantly (P < 0.05) at > 60% VO2peak when there were also more pronounced increases in NE and E.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1996

Effects of physical exercise on some parameters of bone metabolism in postmenopausal women.

This study was performed on 19 postmenopausal female volunteers in a period of five months of moderate physical exercise in order to examine beneficial changes in muscle strength and flexibility as well as changes in sex hormone binding globulin (SHBG) and other parameters related to bone metabolism. While SHBG decreased significantly (from 56.0 +/- 20.0 to 43.9 +/- 16.1 nM, P = 0.009) phosphorus and urea increased (from 2.8 +/- 0.4 to 4.0 +/- 0.5 mg/dl, P = 0.00006 and from 32.1 +/- 9.4 to 42.3 +/- 11.0 mg/dl, P = 0.03, respectively). These changes were accompanied by significant increases in muscle strength and flexibility. Other parameters such as alkaline phosphatase and calcium did not change significantly during the study. Plasma levels of SHBG were negatively correlated with phosphorus. As higher SHBG has been related to increased bone loss in older women, we conclude that moderate physical activity is an effective means to preserve bone loss in postmenopausal women.

Alkaline Phosphatase↗

PubMed1999

Caffeine improves cognitive performance after strenuous physical exercise.

The effects of three carbohydrate electrolyte solutions (CES) containing different amounts of caffeine on cognitive function and the combined effects of these drinks and exercise on cognitive functions were investigated in a double-blind, cross-over study. On five separate occasions, fifteen endurance trained male athletes (23.3 years) received water placebo, CES placebo (68.8 g/l), and three CES drinks containing low, medium and high dosages of caffeine (150, 225 and 320 mg/l). Each occasion, 8 ml/kg of the drink was consumed before -- and 6 ml/kg of the drink was consumed during an all-out 1 hour time trial on a bicycle ergometer. Cognitive (attentional, psychomotor, and memory) tests were carried out immediately before and immediately after exercise. Before exercise, long term memory was improved by CES plus low dose caffeine compared to both placebos. Immediately after exercise, all cognitive functions were improved by CES plus low- and medium-dose caffeine compared to placebo. These results comprise the first practical demonstration of the cognition improving effects of low amounts of caffeine in CES after strenuous physical exercise.

Adult↗