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At least 433 records · Page 24Linked to original sources

PubMed2001

Leukocyte activation, erythrocyte damage, lipid profile and oxidative stress imposed by high competition physical exercise in adolescents.

BACKGROUND: The aim of this study was to evaluate and to compare the lipid profile and the levels of leukocyte activation, red blood cell (RBC) damage and of oxidative stress in two groups of adolescents, with similar body mass index: high competition swimmers and adolescents practising moderate regular physical exercise. METHODS: As markers of leukocyte activation, we measured plasma lactoferrin, elastase and granulocyte-monocyte colony stimulating factor. We studied RBC membrane band 3 profile and membrane-bound hemoglobin, as markers of RBC damage and aging; total and differential leukocyte count and RBC count, hematocrit, hemoglobin concentration and hematimetric indexes were also measured. Lipid profile included the evaluation of triglycerides (TG), total cholesterol (Chol), high-density lipoprotein cholesterol (HDLc), low-density lipoprotein cholesterol (LDLc), apolipoproteins AI and B (Apo AI and B), and lipoprotein (a) (Lp(a)). To evaluate oxidative stress, lipoperoxidation products and total antioxidant capacity were measured. RESULTS: We found that high competition adolescents presented increased plasma levels of leukocyte activation products, increased RBC damage suggesting aging and premature removal, and higher oxidative stress. Lipid profile showed some risk and some protective changes. CONCLUSIONS: Our data suggest that high competition exercise, by imposing a higher and sustained oxidative and proteolytic stress, may contribute in the future to a higher risk of cardiovascular disease. We believe these findings warrant a reevaluation of current views in the intensity, duration and regularity of physical exercise, and that the evaluation of leukocyte activation products, RBC damage, oxidative stress and lipid profile may represent good markers to establish putative protective thresholds.

Adolescent↗

PubMed1998

Effect of physical exercise on cartilage volume and thickness in vivo: MR imaging study.

PURPOSE: To quantify, with magnetic resonance (MR) imaging, the in vivo changes in cartilage volume and thickness after physical exercise. MATERIALS AND METHODS: The patellae of eight volunteers were imaged six times at physical test by using a spoiled fat-suppressed gradient-echo sequence with an acquisition time of 4.10 minutes. The volunteers then performed 50 knee bends, and two more data sets were acquired 3-7 minutes and 8-12 minutes after exercise. The patellar cartilage volume was determined after three-dimensional reconstruction, and the thickness was assessed with a three-dimensional minimal-distance algorithm. RESULTS: Whereas repositioning had a small effect on the measurements (mean coefficient of variation, 1.4%), a statistically significant decrease in cartilage volume was observed 3-7 minutes (mean decrease, 6.0%; P < .05) and 8-12 minutes (mean decrease, 5.2%; P < .05) after exercise. The deformation was homogeneous throughout the joint surface. In one asymptomatic volunteer, a cartilage lesion became more pronounced after exercise. CONCLUSIONS: MR imaging can be used to investigate the response of articular cartilage to physical exercise in vivo. Patients or volunteers should be allowed a sufficient period of physical rest if quantitative measurements of cartilage volume and thickness are to be undertaken in longitudinal studies.

Adult↗

PubMed1991

Effects of physical exercise on colonic motor activity.

We investigated the effect of physical exercise on colonic motor activity in the fasted and fed states in six conscious dogs. Each dog was implanted with nine strain gauge transducers: three on the proximal, three on the middle, and three on the distal colon. The dogs ran for 1 h on a treadmill at 5 km/h (slope 5%). In the fasted state, the dogs exercised during the 5th h of recording after an overnight fast, and in the fed state during the 1st, 3rd, and 5th postprandial hour. In the fasted state, exercise significantly decreased the frequency of colonic migrating motor complexes (MMCs) but had no effect on the total or the mean duration of contractile states in the proximal, middle, and distal colon. Postprandially, exercise disrupted colonic MMCs and replaced them with nonmigrating motor complexes in all three periods of exercise (1st, 3rd, and 6th h). Exercise also increased the total duration per hour of contractile activity throughout the colon during the 1st and 3rd h and only in the distal colon during the 6th h after the meal. The dogs never defecated during rest in the fasted or the fed state. Shortly after the start of exercise in the fasted and fed states, giant migrating contractions (GMCs) occurred, and they were followed by defecation. In approximately 40% of the experiments, another GMC originated in the proximal colon, approximately 10 min after the first defecation, and migrated caudad up to the middle colon. These GMCs were not associated with defecation but caused mass movements.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1988

Lack of desensitization of catecholamine-induced lipolysis in fat cells from trained and sedentary women after physical exercise.

A study was designed to assess whether a period of physical exercise (100 min; 60% of maximal aerobic power), known to promote sympathetic nervous system activation, had a functional impact on human fat cell responsiveness to catecholamines and beta-agonists. The lipolytic activity of isolated sc fat cells was measured before and after a period of exercise in trained and sedentary women with a similar body mass index values [20.4 +/- 0.5 (+/- SE) and 21.3 +/- 0.5 kg/m2] and an equivalent mean fat cell volume (0.216 +/- 0.022 vs. 0.278 pm 0.026 nL). Before exercise, compared with those of sedentary women, the adipocytes of trained women had greater lipolytic responsiveness to catecholamines and beta-agonists; moreover, dibutyryl cAMP had greater lipolytic efficiency on the adipocytes of the trained women. These results suggest that the differences in responsiveness of the adipocytes from sedentary and trained women are due to functional differences at a postreceptor level of the lipolytic cascade. The lipolytic (beta-adrenergic) and antilipolytic (alpha 2-adrenergic) responses of the adipocytes from both groups did not change after the period of physical activity. These results demonstrate, whatever the physical condition of the subjects, that desensitization of beta- and alpha 2-adrenergic responsiveness does not occur after a period of intense physical activity which promotes physiological activation of the sympathetic nervous system.

Adipose Tissue↗

PubMed1980

Influence of propranolol on catecholamine concentration in blood of normotensive man during physical exercise and dependence of the drug effect on dosage intervals.

Physical exercise on a bicycle ergometer caused in normotensive subjects an overshooting increase of plasma noradrenaline and adrenaline concentration, when exercise test was performed during acute or chronic treatment with propranolol both 2 hours after the last intake of the beta receptor blocking agent. At the same time heart rate and blood pressure during exercise were significantly reduced by the drug. But 8 hours after intake of the drug there was a dissociation between the drug effect on plasma catecholamine concentration and its effect on heart rate and blood pressure. While heart rate and blood pressure still were effectively lowered, the influence on plasma catecholamine concentration had already disappeared. The results demonstrate that an increase of plasma catecholamine concentration caused by the adrenergic beta receptor blocking agent propranolol, is strongly dependent on the time interval between measurement of drug effect and the last intake of the drug.

Adult↗

PubMed1983

[Ergospirometric evaluation of 53 physical exercises used in cardiological rehabilitation].

Fifty-three calisthenics used in a cardiac rehabilitation program were evaluated in a group of patients who, 30-60 days after myocardial infarction, had undergone a multistage symptom-limited bicycle exercise test without S-T segment modifications or arrhythmias. The following measurements were made oxygen uptake (VO2), oxygen uptake/Kg (VO2/Kg), ventilation/m' (VE), heart rate/m' (HR), systolic blood pressure (sBP) and METS. A good correlation was observed during the physical exercises between HR and VO2 (r = 0.59; p less than 0.001) and between HR and VO2/Kg (r = 0.64; p less than 0.001). Such correlation was similar to that observed during bicycle ergometric test. Lower values were obtained for the correlations between sBP and both VO2 and VO2/Kg, but they were still statistically significant (p less than 0.001). Heart rate and sBP were lower during calisthenics than during bicycle exercise from a VO2 level of 600-800 ml up. It is therefore possible to tailor a safe training program based on calisthenics whose level of energy expenditure is known: HRxsBP reached during such physical exercises will be lower than during bicycle ergometric test, VO2 being equal.

Adult↗

PubMed2005

Effects of L-carnitine on thyroid hormone metabolism and on physical exercise tolerance.

L-carnitine (CARN) is a water-soluble, naturally occurring quaternary amine ubiquitous in biological fluids and animal tissues; in these tissues, CARN plays an important role in energy metabolism. Skeletal muscles store about 95 % of a total of 20 g CARN contained in the adult human body, but high-intensity physical exercise decreases the CARN muscle content. The daily allowance of CARN is mainly satisfied by diet. Keeping in mind important interstudy differences, the general conclusion is that CARN supplementation may enhance athletic performance when coupled to physical exercise itself. Healthy, essentially sedentary persons and untrained individuals do not benefit from supplementation, and certainly not if CARN is administered for a few days. CARN was also shown to modulate thyroid hormone action in peripheral tissues, the most frequent modulation observed being inhibition.

Animals↗

PubMed1982

Effects of prolonged physical exercise and fasting upon plasma testosterone level in rats.

Prolonged physical exercise and fasting in male rats were studied to determine the effect of these two treatments on plasma testosterone level. Blood and tissue samples were drawn after 1 h, 3 h, 5 h, and 7 h treadmill running, and after 24 h, 48 h, and 72 h of fasting. Both treatments resulted in a significant fall in plasma testosterone, plasma luteinizing hormone (LH), plasma Insulin (IRI) and in liver and muscle glycogen stores. In the course of these two treatments the injection of a supra maximal dose of Human Chorionic Gonadotropin (HCG) produced a rise in plasma testosterone similar to that in control rats. This indicates that the decrease of plasma LH may be responsible for the decrease in plasma testosterone, which is time-related with the decrease in glycogen stores. The possible metabolic role of the decrease in plasma testosterone is discussed.

Animals↗

PubMed1996

The effect of erythropoietin on lactate, pyruvate and excess lactate under physical exercise in dialysis patients.

To investigate EPO-induced increase of hemoglobin on energy metabolism plasma concentrations of lactate (L), pyruvate (P) and excess lactate (XL) were determined in ten dialysis patients at rest, immediately after 6 minutes of ergometric exercise as well as after recovery for 15 and 30 min. The investigations were performed before EPO-therapy at a mean Hb = 7.5 +/- 0.9 g/dl and under EPO-therapy at a mean Hb = 10.0 +/- 0.6 g/dl and at a mean Hb = 11.9 +/- 0.8 g/dl. Ten healthy subjects were subjected to the same investigation at Hb = 14.7 +/- 1.1 g/dl. There was a significant rise of L and XL in all patient groups under ergometric exercise. The increase of hemoglobin from 7.5 g/dl to 10.0 g/dl led to significantly (p < 0.01) lower L and XL concentrations immediately after exercise (L = 4.62 vs 3.23 mmol/l, XL = 2.37 vs 1.38 mmol/l). The further decrease of the mean L and XL values (L = 2.88 mmol/l, XL = 1.05 mmol/l) associated with the rise of hemoglobin to 11.9 g/dl could not be confirmed statistically. In contrast to all patient groups, there was no significant rise in XL in the healthy control subjects under physical exercise. The present results make it evident that patients with renal anemia react even to light physical exercise with pronounced tissue hypoxia in contrast to healthy subjects. The increase of the hemoglobin content under the EPO-therapy leads to a marked reduction of the tissue hypoxia and consequently of anaerobic energy production. A further rise of the hemoglobin content above and beyond 10.5 g/dl will have an additional positive effect on oxygen supply only in occasional cases. The comparison with healthy subjects shows that despite a very large degree of normalization of the hemoglobin content, no normalization of energy metabolism can be attained.

Anaerobic Threshold↗

PubMed1991

Influence of aging, training and acute physical exercise on plasma glutathione and lipid peroxides in man.

In trained (long-distance runners) and untrained volunteers aged 22 to 57 years, basal plasma glutathione (GSH) concentration decreased significantly with increasing age. In most age groups basal GSH concentration of oxidized glutathione (GSSG) and lipid peroxides (LPO) was not influenced either by age or by training. Following acute physical exercise (bicycle ergometric test), which was maximal for each person and thus different in trained and untrained persons, plasma GSH, GSSG, and LPO concentrations were not changed at all in untrained volunteers. In trained persons, however, GSH concentration was significantly decreased by about 30%. Surprisingly, we observed a decrease in plasma LPO content by about 40%. GSSG content was not altered. The comparison with some physical-physiological parameters indicates that the changes in GSH and LPO concentrations depend on the extent of acute physical exercise rather than on previous training. Alterations of GSH and LPO in plasma could be of physiologic significance.

Adult↗

PubMed1998

Randomized trial of physical exercise alone or combined with bright light on mood and health-related quality of life.

BACKGROUND: So-called atypical depressive symptoms (carbohydrate craving, prolonged sleep, weight gain, increased appetite) frequently emerge in association with low illumination to which people are ordinarily exposed indoors, or even outdoors at extreme latitudes in wintertime. Our objective was to analyse the effect of physical exercise alone or combined with bright light on mood and the health-related quality of life during winter. METHODS: We carried out a randomized controlled trial on 120 indoor employees in southern Finland between November and January. The subjects were allocated to supervised fitness training under bright (2500-4000 lx) or ordinary (400-600 lx) light conditions in a gym 2-3 times weekly for 8 weeks, or supervised relaxation training once a week over the same period as active placebo. We collected questionnaire data on the changes in mood and health-related quality of life after 4 and 8 weeks of training, and after 4 months follow-up. RESULTS: Fitness training in bright light resulted in greater relief from atypical depressive symptoms and more vitality than in ordinary room light. Compared with relaxation alone, the former regime improved general mental health and social functioning in addition to the improvement in depressive symptoms and vitality, whereas the latter only increased vitality. CONCLUSIONS: Supervised physical exercise combined with exposure to bright light appears to be an effective intervention for improving mood and certain aspects of the health-related quality of life in wintertime. This effect appears unrelated to the history of season-dependent symptoms, being noticeable among healthy individuals.

Adult↗

PubMed1993

Noradrenergic and hormonal responses to physical exercise in adolescents. Relationship to anxiety and tolerance to frustration.

Seventy physically healthy 14-year-old adolescents, 40 boys and 30 girls, were evaluated psychologically and endocrinologically. After the psychological tests (Anxiety Score Test for Adolescents, Rosenzweig, Pictures Frustration Test for Children), subjects were divided into group A, with low anxiety/sense of guilt and high self-esteem/tolerance to frustration and group B with the opposite. In both groups, we measured basal plasma levels of noradrenaline (NE), growth hormone (GH), prolactin (PRL), melatonin (MT) and luteinizing hormone (LH) and their response to physical exercise (the Harvard step test). Basal levels of the hormones and of NE were not different in the two groups. After the physical stimulus, NE levels rose significantly more in B girls than in A and significantly less in B than in A boys. GH and PRL levels increased only in A girls and MT in B boys, while LH levels decreased in A boys and girls but not in B subjects.

Adolescent↗

PubMed1997

Heavy physical exercise decreases nitric oxide levels in the nasal airways in humans.

A continuous production of nitric oxide (NO) takes place in human nasal airways. NO in the nasal airways is mainly derived from the paranasal sinuses. The factors that regulate NO synthesis in the upper airways are presently not known. We have investigated the effects of physical exercise on NO levels in the nasal airways. Nasal cavity NO levels were measured by chemiluminescence technique in five healthy non-smoking male subjects before, during and after 5 min of maximal exercise (245 W) on an ergometer cycle. In addition, in one subject NO levels were measured directly in the maxillary sinus during exercise. Nasal cavity NO levels were decreased by 47% after only 1 min of exercise compared with the control situation. A maxima 76% reduction was found at the end of the exercise period and thereafter NO levels slowly increased, reaching basal levels again in about 15-20 min. NO levels in the sinus decreased in a similar manner during exercise. The decrease in nasal cavity NO levels cannot be explained merely by dilution of nasal air due to changes in nasal cavity volume or increased ventilation. We conclude that the excretion of NO in the nasal airways is decreased acutely during heavy short term physical exercise.

Adult↗

PubMed2003

A 3 year follow-up study of health care students' sense of coherence and related smoking, drinking and physical exercise factors.

The purpose of the study was to describe the sense of coherence (SOC) of three groups of Finnish polytechnic students (n=287) at the beginning of their studies and to follow it during a period of 3 year amongst the health care students (n=63) of this group. The associations between SOC and smoking, drinking and physical exercise were also studied. The data were collected with a questionnaire which included Antonovsky's (Adv. Nurs. Sci. 1(1983)37) SOC scale. Data analysis was with SPSS statistical software. The students showed a strong sense of coherence at the beginning of their studies. Physical activity was related to the strength of SOC, but no association was found with smoking and drinking. Health care students showed a stronger SOC at the beginning of their studies than the two other groups. During the follow-up focused on the health care students, SOC weakened in 6%, remained unchanged in 65% and strengthened in 32% of the participants. Smoking, drinking and physical exercise showed no association with these changes. Future research should be focused on identifying factors that are related to SOC during education.

Adolescent↗

PubMed1984

Cholinergic mediation of growth hormone secretion elicited by arginine, clonidine, and physical exercise in man.

The role of acetylcholine in human GH secretion was studied with atropine, which selectively blocks cholinergic muscarinic receptors and crosses the blood-brain barrier. Paired tests were performed in 22 normal subjects divided into 4 groups. The stimuli employed were arginine (30 g/30 min, iv), clonidine (300 micrograms, orally), physical exercise for 20 min, and saline. In the second test, atropine (1 mg, im) was administered before GH stimulation. Arginine elicited a GH secretory peak of 16.6 +/- 5 ng/ml (mean +/- SEM), which was completely blocked when atropine was administered with arginine (0.9 +/- 0.1 ng/ml). Atropine did not, however, modify the PRL secretory response; peak levels after arginine and atropine plus arginine were 16.3 +/- 3.1 and 16.8 +/- 2.5 ng/ml, respectively. Clonidine elicited a GH secretory peak (11.8 +/- 2.7 ng/ml) which also was blocked by pretreatment with atropine (1.2 +/- 0.2 ng/ml). Neither clonidine nor clonidine plus atropine altered PRL secretion. GH levels also were sharply increased after physical exercise, with a peak level of 19.4 +/- 4.9 ng/ml. Atropine completely blocked exercise-induced GH secretion (2 +/- 0.9 ng/ml). Atropine alone did not modify GH or PRL values compared with saline administration. The potency of the atropine-induced suppression of GH secretion by three different stimuli, each with presumably different mechanisms of action, suggests that acetylcholine plays an important role in the regulation of GH secretion.

Acetylcholine↗

PubMed1987

Physical exercise and antihypertensive drugs.

Interactions and interrelations between antihypertensive drugs (AHD) and physical exercise are discussed on the basis of experimental results and of literature data. In physically active subjects AHD should lower the arterial pressure not only at rest, but also during physical stress. On the other hand, antihypertensive treatment should not influence physical performance. The main groups of AHD which could by applied in predominantly young and otherwise healthy subjects are: Beta-receptor blockers are recommended as first choice since they have a marked lowering effect on exercise blood pressure, conversely they impair by the same mechanism sympathetic stress adaptation. The effect of diuretics and calcium antagonists on exercise pressure is generally small; however, it may vary greatly in individual cases. As an interesting new category ACE-inhibitors should be studied further. Most AHD may impair the performance capacity of competitive athletes; however, sometimes they are also used illicitly to improve performance. In contrast, the symptom-limited performance of hypertensives is generally improved by therapy.

Antihypertensive Agents↗

PubMed2004

Women's behaviour, beliefs and information sources about physical exercise in pregnancy.

OBJECTIVE: To examine the potential effect of low-risk pregnancy on women's recreational activity patterns and to explore pregnant women's beliefs and information sources regarding physical exercise participation. DESIGN: Preliminary, prospective survey SETTING: Participants' homes in the East Midlands, UK. PARTICIPANTS: Fifty-seven nulliparous, pregnant women. MEASUREMENTS: Levels of maternal physical activity participation were assessed by semi-structured interview at 16, 25, 34 and 38 weeks gestation. The modified Baecke questionnaire provided a measure of women's habitual sport and leisure activities in the 12 months prior to pregnancy. A 10-item scale assessed maternal beliefs regarding the importance of physical activity in pregnancy. The fetal health locus of control scale measured the extent to which women believed their own behaviour, the behaviour of others and/or chance would influence fetal health. Open-ended questions assessed women's information sources. FINDINGS: Fourteen of the 36 (39%) women who reported participating in some form of weekly exercise before pregnancy did not report pursuing any similar activities during pregnancy. Rest and relaxation were perceived as being significantly more important during pregnancy than was regular exercise or the maintenance of an active lifestyle. Fifty-five respondents (96%) indicated that they had received advice about physical activity at least once during pregnancy. At 16 weeks gestation, women obtained most of their information from books and magazines. Between 25 and 38 weeks gestation, most advice came from family and friends. Participants who reported receiving this advice were significantly older, more educated and of a higher activity level pre-pregnancy. KEY CONCLUSIONS: Levels of maternal exercise may decline during pregnancy both as a result of the physical changes of pregnancy and from a combination of social and psychological factors. Present health education may be failing to correct inaccurate perceptions of the risks associated with physical exercise in pregnancy. IMPLICATIONS FOR PRACTICE: Improving the quantity and quality of information related to physical exercise has the potential to correct inaccurate perceptions and confer several benefits on maternal and fetal health. Effective intervention strategies should focus not only on the pregnant woman but also extend to her family, friends and exercise provider.

Adaptation, Psychological↗

PubMed2002

Physical exercise, sports, and lung function in smoking versus nonsmoking adolescents.

Associations between adolescent smoking habits and exercise, particularly participation in sports and lung function were studied. All students aged 13-19 yrs in Nord-Trøndelag County, Norway, 1995-1997, were invited to join a cross-sectional study. Information on smoking habits and exercise was obtained by self-administered questionnaire. Spirometry was performed in accordance with American Thoracic Society standards. Of the 6,811 students (aged 13-18 yrs, without asthma), 2,993 (44%) reported never-smoking, and 1,342 (20%) reported current smoking (90% daily). Frequency of physical exercise was inversely associated with smoking, but participants in individual sports with lesser endurance, especially body-building and fighting sports, were more likely to be daily smokers than nonparticipants. Both daily (53%) and occasional smokers (43%) were more likely to have quit sports than never-smokers (26%)). Never-smokers showed a positive dose-response between physical exercise and lung function (forced vital capacity and forced expiratory volume in one second, adjusted for age and height). No similar significant association was observed in daily smokers. These data suggest that smoking habits in different sports should be considered when promoting physical activity as smoking prevention, and sports organizations should include smoking prevention programmes. Adolescents with better lung function may self-select into sports; this possibility needs to be studied in a longitudinal design.

Adolescent↗