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At least 775 records · Page 43Linked to original sources
PubMed1984

Variations of serum testosterone concentrations after physical exercises of different duration.

Serum testosterone concentration was determined before and after physical activities of different duration. The subjects under study were: (1) 7 competitive walkers before and after a 20-km race (average race time 1 h 30 min); (2) 9 middle-distance runners before and after 1-h training; (3) 16 marathon runners before and after a marathon run (average running time 2 h 33 min); (4) 30 ultramarathon runners before and after a 107-km race (average running time 14 h). Serum testosterone increased by 51.8% (NS) in competitive walkers, by 38.2% (P less than 0.05) in middle-distance runners, and by 44.9% (P less than 0.01) in marathon runners; it decreased by 31.9% (P less than 0.001) in the ultramarathon runners. These findings, and similar variations of serum testosterone observed in an ultramarathon runner during a 6-h training session, suggest that serum testosterone increases during physical activities lasting up to 3 h and decreases to or even below the pre-exercise values for longer physical efforts. The possible mechanisms responsible for these differences are discussed.

Adolescent↗
PubMed1995

Effects of physical exercise and aging on ascorbic acid and superoxide anion levels in peritoneal macrophages from mice and guinea pigs.

The relationship of physical activity and aging, two processes with a high production of oxygen-free radicals to the ascorbate and superoxide anion (O2-) contents of peritoneal macrophages was studied in two animals species: guinea-pig (in which ascorbic acid is a vitamin) and mouse (in which ascorbic acid is not a vitamin). The effects of exhaustive exercise were examined in young and old animals. The results show that macrophages from old animals have a lower ascorbate content than those from young ones, whereas with exercise the ascorbate content increased in both old and young animals. This increase was higher in young than in old animals, and more evident in mice than in guinea-pigs. Aging also resulted in an increase in the O2- levels of macrophages. With exercise these levels decreased in young mice but increased in young guinea-pigs. In old animals the exhaustive exercise did not change the O2- levels. The results suggest in general a lack of correlation between the intracellular ascorbate and O2- levels in relation to both physical exercise and aging.

Aging↗
PubMedDate not supplied

[Vibration, back pain and physical exercise in high-risk professionals: a cross-sectional study].

Repeated loads and vibration stress in professional settings are relevant risk factors for back pain. Aim of this cross-sectional study was to estimate: a) the prevalence of back pain in two high-risk professional samples (helicopter pilots and bus drivers); b) the association between physical/sports exercise and back pain subjective perception across age. Prevalence of back pain is 94% in helicopter pilots and 74% in bus drivers; prevalence of back pain significantly increases with age. The positive effect of regular physical/sports exercise on subjective back pain significantly decreases with age. Physical or sports exercise adapted to structural characteristic of patients can result effective in diminishing personal impairment in subjects at professional risk.

Adolescent↗
PubMed1978

Carbohydrate, lipid and amino acid metabolism following physical exercise in man.

To elucidate early metabolic adaptations of physical training obese and nonobese subjects were studied before and at different intervals after 1 h of bicycle exercise at 70% of maximal working capacity. Four h after exercise intravenous glucose tolerance (IVGT) and plasma level of alanine were decreased. Compared to the diurnal variation plasma concentration of cortisol was increased. Twenty-four hours after exercise plasma concentrations of cortisol and trihlycerides were decreased. Furthermore, plasma insulin during IVGT test was decreased and blood glycerol increased in the obese subjects. There were no changes in basal insulin, IVGT, or plasma levels of amino acids which were elevated in the obese subjects (valine, isoleucine, leucine, tyrosine, phenylalanine). Forty-eight hours after exercise plasma insulin during IVGT test and plasma triglycerides remained decreased in the obese subjects. Low cortisol levels 24 h after exercise might result in increased insulin effect leading to low plasma insulin levels seen in physically trained subjects. Elevated glycerol levels in the obese subjects might be the first sign of diminishing fat stores secondary to increased lipolysis.

Adult↗
PubMed2002

[Effect of physical exercise on bone mass in the elderly].

Reduced physical activity or immobilisation have several negative effects on the skeleton. Significant reductions in bone mass have been observed after prolonged bed rest, in patients with injury to the spinal cord and hemiplegia, and after transitory immobilisation of the extremities, for instance after fractures. The aim of this literature review was to evaluate the effect of exercise on bone mass in elderly people and to determine whether exercise programmes could be appropriate in the prevention of fractures in this segment of the population. We identified four randomised and two non-randomised, prospective studies for the analysis of the effect of exercise on bone mass. Four studies reported a statistically significant difference in the intervention group, as compared to the control group, whereas two studies failed to find any significant differences in bone mass. We conclude that exercise has a beneficial and measurable effect on bone mass in the elderly, which may lead to a decline in the rate of fractures.

Aged↗
PubMed2001

Biventricular response to supine physical exercise in young adults assessed with ultrafast magnetic resonance imaging.

Simultaneous assessment of left ventricular (LV) and right ventricular (RV) response to exercise is limited with the current imaging modalities. Magnetic resonance imaging (MRI) techniques are now under development that allow near real-time evaluation of biventricular function under physical stress. This approach may open new avenues to study heart function in response to exercise in health and disease. The aim of this study was to evaluate biventricular response to supine physical exercise using ultrafast MRI. Biventricular volumes and function were examined in 16 healthy volunteers (mean age 18 +/- 2 years) using an ultrafast MRI sequence at rest and during an exercise protocol on a MRI compatible bicycle ergometer. Exercise level was individualized at the workload corresponding to 60% of the maximal oxygen uptake. All subjects completed the exercise MRI examination, allowing functional evaluation. Stroke volume of both ventricles increased from rest to exercise (left ventricle, 89 +/- 14 ml vs 102 +/- 19 ml, p < 0.05; right ventricle, 88 +/- 14 ml vs 101 +/- 16 ml, p < 0.05). Ejection fraction also increased in both ventricles from rest to exercise (left ventricle, 63 +/- 6% vs 74 +/- 6%, p < 0.05; right ventricle, 61 +/- 6% vs 70 +/- 6%, p < 0.05). End-systolic volume of the left and right ventricles decreased from rest to exercise (left ventricle, -33 +/- 12%, p < 0.05; right ventricle, -25 +/- 12%, p < 0.05), whereas LV and RV end-diastolic volumes remained unchanged. The results fit well with current concepts of cardiac physiology, and therefore we conclude that ergometer-induced exercise MRI is a valid approach to assess physiologic changes in LV and RV function simultaneously.

Adolescent↗
PubMed2006

Effects of physical exercise on quality of life, exercise capacity and pulmonary function in children with asthma.

OBJECTIVE: To investigate the effects of regular submaximal exercise on quality of life, exercise capacity and pulmonary function in asthmatic children. PATIENTS AND METHODS: Sixty-two children with mild-moderate asthma (mean age 10.4 (SD 2.1) years) were randomly allocated into exercise and control groups. The exercise group underwent a moderately intensive basketball training program for 8 weeks. A home respiratory exercise program was advised to both groups. Pediatric Asthma Quality of Life Questionnaire (PAQLQ) was used for the evaluation of activity limitation, symptoms and emotional functions. Exercise capacity was evaluated through the physical work capacity (PWC 170 test) on a cycle ergometer and 6-minute walk test. Spirometric tests were also performed and medication and symptom scores were recorded. RESULTS: Although PAQLQ scores improved in both groups, the improvement in the exercise group was significantly higher. The exercise group performed better in the PWC 170 and 6-minute walk tests, whereas no improvement was detected in the control group at the end of the trial. Medication scores improved in both groups, but symptom scores improved only in the exercise group. No significant changes were detected in pulmonary function in either group, except for peak expiratory flow values in the exercise group. CONCLUSION: Eight weeks of regular submaximal exercise has beneficial effects on quality of life and exercise capacity in children with asthma. Submaximal basketball training is an effective alternative exercise program for asthmatic children.

Adolescent↗
PubMed2005

Physical exercise prevents age-related decline in precursor cell activity in the mouse dentate gyrus.

Physical activity induces adult hippocampal neurogenesis. We here show that the acute up-regulating effect of voluntary wheel running on precursor cell proliferation decreases with continued exercise, but that continued exercise reduces the age-dependent decline in adult neurogenesis. Cell proliferation peaked at 3 days of running. After 32 days of exercise this response returned to baseline. Running-induced proliferation of transiently amplifying progenitor cells led to a consecutive increase in the number of more mature cells. Increasing age reduced adult neurogenesis at 9 months to 50% of the value at 6 weeks and to 17% at the age of 2 years. At both 1 and 2 years, precursor cell divisions remained inducible by physical activity. Exercise from 3 to 9 months of age significantly reduced the age-dependent decline in cell proliferation but (presumably in the absence of additional stimuli) did not maintain net neurogenesis at levels corresponding to a younger age. We propose that physical activity might contribute to successful aging by increasing the potential for neurogenesis represented by the pool of proliferating precursor cells.

Aging↗
PubMedDate not supplied

[Physical exercise during hemodialysis session: effect on quality of life].

There are many studies showing beneficial psychophysical effects of exercise in dialyzed patients. Moreover, it has been suggested that exercise positively correlates with better metabolism, better blood pressure control and with total hemoglobin. In our dialysis unit eight dialyzed patients (average age = 66.7 years), for eight weeks participated in physical training with bike (Reck Moto Med Letto) during dialysis treatment. Controls of glucose metabolism, blood pressure and dialysis efficiency index (Kt/V and URR) at rest and during exercise was performed. All patients responded well to exercise and expressed better muscular performance during and after exercise time. Our study showed in all patients improvement of Kt/V and URR index after physical exercise period, compared to exercise free time (p < 0.005). We suggest that exercise during dialysis treatment is safe and consents either better psychophysical performance or better dialytic efficiency.

Aged↗
PubMed2005

The in vivo effect of melatonin on cellular activation processes in human blood during strenuous physical exercise.

Melatonin has been reported to have anti- as well as pro-inflammatory properties. Because physical stress is associated with the activation of blood cells, the present study examines melatonin's role in exercise-induced cell activation processes. Eight healthy volunteers (aged 20-62 yr, mean = 31), exercised on an 'Ergometric' bike for 30 min at 80% of their calculated maximum pulse rate. Blood samples were taken just before melatonin administration, directly after exercise, and 2 hr after exercise completion. Cytokine and eicosanoid parameters were measured in plasma from blood stimulated with lipopolysaccharide (LPS) for 2 hr whereas tissue factor (TF) activity was measured in isolated monocytes. Melatonin significantly decreased LPS-induced TF activity by 48% (P < 0.01) directly after exercise, and a 44% reduction was seen 2 hr later (P < 0.02). Furthermore, melatonin significantly reduced the lymphocyte count rise produced directly after exercising by more than 30% (P < 0.01). A trend was also seen for melatonin suppressing the increase of WBC by around 10% and to strengthen the platelet increase by about 8% after physical stress. Melatonin also significantly lowered RBC and hemoglobin counts by 5 and 3-4% during exercise (P < 0.005 and <0.02 respectively). Two hours after exercise, melatonin tended to lower leukotriene B4 levels by 30%. Interleukin-8 and tumor necrosis factor-alpha levels tended to be lower in individuals who had taken melatonin following hard physical activity and a larger sample size may show significance. Thromboxane B2 production seemed unaffected by melatonin during exercise. In conclusion, in vivo intake of melatonin appears to suppress LPS-induced activation of monocytes in whole blood reactions associated with physical exercise and facilitates the down-regulation of inflammatory mediators.

Adult↗