Different behavior of phagocytes in young and old subjects]

Ageing is a dynamic phenomenon in which there is a physiological decay in all the functions of the individual. The consequence is an increased susceptibility to infections, autoimmune diseases and cancer. Phagocytic cells as polymorphonuclear leukocytes (PMNL) and monocytes (Mo) are of prime importance in the defence against invasive agents, PMNL and Mo seek out and destroy invading micro-organisms. Chemotaxis and phagocytosis are two mechanisms that are activated by these cells for this purpose. In this study, using "in vitro" techniques, we have verified if, at the level of such functions of cell defense, there could be variations in elderly subjects with respect to younger subjects. Our results show a chemotactic activity of PMNL in the elderly that is higher and a phagocytic activity that is lower. As regards Mo, there is a lower chemotactic activity in the elderly and only a slight difference in phagocytic activity with respect to the younger subjects. These results are in agreement with those found at the clinical level showing the elderly less protected from infection with respect to younger subjects.     

Effects of endurance training on the cardiovascular system and water compartments in elderly subjects

Pickering, Gisèle P., Nicole Fellmann, BéatriceMorio, Patrick Ritz, Aimé Amonchot, Michel Vermorel, and JeanCoudert. Effects of endurance training on the cardiovascularsystem and water compartments in elderly subjects. J. Appl. Physiol. 83(4): 1300-1306, 1997.Theeffects of endurance training on the water compartments and thecardiovascular system were determined in 10 elderly subjects [age62 ± 2 yr, pretraining maximal oxygen consumption(O_{2 max})/kg = 25 ± 2 ml · min¹ · kg¹body wt]. They trained on a cycloergometer 3 times/wk for 16 wk(50-80%O_{2 max},then 80-85%O_{2 max}). They werechecked at 8 wk, 16 wk, and 4 mo after detraining. Training improvedO_{2 max} (+16%) andinduced plasma volume expansion (+11%). No change in total body water,extracellular fluid, interstitial and intracellular fluid volumes,fat-free mass, and body weight was detected in this small sample withtraining. Body fat mass decreased (2.1 ± 2.2 kg).Echocardiography at rest showed increased fractional shortening andejection fraction and decreased left ventricular end-systolic dimension(P < 0.05). Blood volume expansioncorrelates with cardiac contractility and has an impact on cardiacfunction. These improvements are precarious, however, and arecompletely lost after 4 mo of detraining, when elderly subjects losethe constraints and the social stimulation of the imposed protocol.

     

Bone mechanical properties after exercise training in young and old rats

The effects of a 10-wk training regimen on the mechanical properties of the femur and humerus were evaluated in 2.5- and 25-mo-old Fischer 344 female rats. The rats trained on a rodent treadmill 5 days/wk for 10 wk. Duration, grade, and speed increased until the rats maintained 1 h/day at 15% grade and either 15 m/min (old rats) or 36 m/min (young rats). Excised bones were mechanically tested with a 3-point flexure test for mechanical properties of force, stress, and strain. Fat-free dry weight (FFW) and moment of inertia were also obtained. With aging, similar increases were observed in both the femur and humerus for FFW, moment of inertia, and force. Ultimate stress was reduced in the senescent femur while strain was elevated; a similar but nonsignificant trend was observed in the humerus. Irrespective of age, training increased FFW in the femur and, to a lesser degree, in the humerus. Breaking force was elevated for both bones after training. In young and old bones, the training-induced differences in bone mass and force were similar, despite differences in training intensity. In the old trained rats, femur ultimate stress was greater than that in control rat femurs and similar to that in young rat femurs. The results of the present study indicate that training effects were not limited by age.     

Growth hormone response induced by a respiratory muscle endurance training in healthy subjects

To date, the large majority of studies evaluating growth hormone (GH) response to acute physical exercise has been performed involving gross muscle groups. To the best of our knowledge, none has evaluated the effects of a respiratory muscle endurance training (RMET) on hormonal secretions, particularly on GH release, though some respiratory devices have been widely used in athletes to train respiratory muscles and to improve cardiopulmonary function and physical performance. 8 healthy men underwent an incremental progressive RMET protocol of 11 daily sessions, obtained through the use of a specifically designed respiratory device (Spiro Tiger?). The 12th session of RMET (15 min duration: 1 min at a respiration rate of 28 acts/min, 5 min at 32 acts/min, 5 min at 34 acts/min, 4 min at 36 acts/min) was associated with blood samplings for determination of GH, cortisol, ghrelin, glucose, and lactate (LA) levels. GH and cortisol responses significantly increased after a 15-minute RMET session, which, in contrast, inhibited ghrelin secretion. There was a minimal, though significant, increase in LA levels with a significant elevation in glycemia. A 15-minute RMET session, administered after a 11-days incremental progressive RMET protocol, was capable of stimulating GH and cortisol release and suppressing ghrelin secretion. Optimization of incremental progressive RMET protocols would be important to maximize the positive chronic effects of this intervention on somatotropic function and muscle performance.     

Influence of resistance training on cardiorespiratory endurance and muscle power and strength in young athletes

The purpose of this study was to investigate the influence of additional resistance training on cardiorespiratory endurance in young (15.8 ± 0.8 yrs) male basketball players. Experimental group subjects (n=23) trained twice per week for 12 weeks using a variety of general free-weight and machine exercises designed for strength acquisition, beside ongoing regular basketball training program. Control group subject (n=23) participated only in basketball training program. Oxygen uptake (VO(2max)) and related gas exchange measures were determined continuously during maximal exercise test using an automated cardiopulmonary exercise system. Muscle power of the extensors and flexors was measured by a specific computerized tensiometer. Results from the experimental group (VO(2max) 51.6 ± 5.7 ml.min(-1).kg(-1) pre vs. 50.9 ± 5.4 ml.min(-1).kg(-1) post resistance training) showed no change (p>0.05) in cardiorespiratory endurance, while muscle strength and power of main muscle groups increased significantly. These data demonstrate no negative cardiorespiratory performance effects on adding resistance training to ongoing regular training program in young athletes.     

Effect of endurance training and seasonal fluctuation on coagulation and fibrinolysis in young sedentary men

Van den Burg, P. J. M., J. E. H. Hospers, M. Van Vliet, W. L. Mosterd, B. N. Bouma, and I. A. Huisveld. Effect of endurance training and seasonal fluctuation on coagulation and fibrinolysis inyoung sedentary men. J. Appl. Physiol.82(2): 613-620, 1997.The effect of 12 wk of submaximal trainingon hemostatic variables was studied in 20 young sedentary men (Tr) and19 nontraining matched controls (Con). After training, a morepronounced increase in factor VIII coagulant activity(P < 0.01), reflected in a decrease in activated partial thromboplastin time(P < 0.01) during maximal exercise,was seen. Both basal plasminogen activator inhibitor 1 antigen (PAI-1Ag) and activity (PAI-1 Act; P < 0.05), as well as basal and exercise-induced tissue-type plasminogenactivator antigen (t-PA Ag; P < 0.05), were decreased after training. The overall effect onfibrinolysis was reflected in an increase in the t-PA Act/t-PA Ag ratioin the Tr group. In contrast, during the same period (February-June),the Con group demonstrated an increase in basal PAI-1 Ag and PAI-1 Act(P < 0.05), together with anincrease in basal and exercise-induced t-PA Ag(P < 0.05). Both basal andexercise-induced t-PA Act were unchanged, but t-PA Act/t-PA Ag wasdecreased (P < 0.05) in the Congroup. We conclude that physical training promotes both coagulation andfibrinolytic potential during exercise and may reverse unfavorableseasonal effects on fibrinolysis.

     

Norepinephrine spillover at rest and during submaximal exercise in young and old subjects

Mazzeo, Robert S., Chakravarthi Rajkumar, Garry Jennings,and Murray Esler. Norepinephrine spillover at rest and during submaximal exercise in young and old subjects. J. Appl. Physiol. 82(6): 1869-1874, 1997.Aging isassociated with elevations in plasma norepinephrineconcentrations. The purpose of this investigation was toexamine total body and regional norepinephrine spillover as anindicator of sympathetic nerve activity. Eight young (26 ± 3 yr)and seven old (69 ± 5 yr) male subjects were studied at rest andduring 20 min of submaximal cycling exercise at 50% of peak workcapacity. Norepinephrine spillover was determined by continuousintravenous infusion of[³H]norepinephrine.Arterial norepinephrine concentrations were significantly greater atrest for old vs. young subjects (280 ± 36 vs. 196 ± 27 ng/ml,respectively). Whereas total norepinephrine spillover did not differbetween groups at rest, hepatomesenteric norepinephrine spillover was50% greater in old subjects compared with their young counterparts (51 ± 7 vs. 34 ± 5 ng/min, respectively). Additionally,norepinephrine clearance rates at rest were significantly lower for theold subjects (23%). During exercise, plasmanorepinephrine concentrations increased compared with rest, with oldsubjects again demonstrating greater values than the young group.Hepatomesenteric norepinephrine spillover was significantly greater(+36%) during exercise for old subjects compared with young; however,no difference was found for whole body spillover rates between agegroups. Norepinephrine clearance rates remained depressed(30%) in the old subjects during exercise. Clearance ofepinephrine mirrored that for norepinephrine both at rest and duringexercise across age groups. It was concluded that in old subjects, areduction in norepinephrine clearance and an increase in regionalnorepinephrine spillover can account for the higher plasmanorepinephrine concentrations observed at rest. This relationship isnot exacerbated by the stress imposed during an acute bout of exercise.

     

Muscle endurance is greater for old men compared with strength-matched young men.

The purpose was to compare the time to task failure for a sustained isometric contraction performed at a submaximal intensity with the elbow flexor muscles by young and old men who were matched for strength. Eight young men (18-31 yr) and eight old men (67-76 yr) sustained an isometric contraction at 20% of maximal voluntary contraction (MVC) torque until the target torque could no longer be achieved for at least 5 s. The maximal torque exerted at the wrist was similar for the young and old men before the fatiguing task (65.9 +/- 8.0 vs. 65.4 +/- 8.7 N x m; P > 0.05), and they experienced similar reductions in MVC torque after the fatiguing contraction (31.4 +/- 10.6%; P < 0.05). The time to task failure was longer for the old men (22.6 +/- 7.4 min) compared with the strength-matched young men (13.0 +/- 5.2 min; P < 0.05), despite each group sustaining a similar torque during the fatiguing contraction (P > 0.05). The increases in torque fluctuations, electromyographic (EMG) bursting activity, and heart rate were greater for young men compared with the old men, and they were less at task failure for the old men (P < 0.05). Mean arterial pressure increased at a similar rate for both groups of men (P > 0.05), whereas the averaged EMG activity and rating of perceived exertion reached similar values at task failure for the young and old men (P > 0.05). These findings indicate that the longer time to task failure for the old men when performing the submaximal contraction was not due the absolute target torque exerted during the contraction.     

Physical work capacity and effect of endurance training in visually handicapped boys and young male adults

The purpose of the present study was to evaluate the relationship between several physical fitness parameters and eyesight divided into 3 grades in visually handicapped boys and young male adults, and to investigate the effect of mild exercise training on physical and psychic symptoms as well as cardiorespiratory fitness. Four subjects were totally blind (TB), 6 were semi-blind (SB) and 27 had amblyopia (AM). Physical fitness tests consisted of maximal oxygen uptake (Vo2max), maximal pedalling speed and power, maximal stepping rate, and isometric knee extension strength. Compared with AM and SB groups, the TB group was inferior in all physical fitness parameters. Especially, Vo2max, in TB (26 ml.kg-1.min-1) was about 56% of that in age-matched Japanese sighted subjects and was significantly low compared with the AM and SB groups. Both muscle strength and maximal pedalling power corresponded to about 50% that of the age-matched sighted group. Six SB and 4 TB students (mean = 17.7 years) were trained for 6 weeks on a bicycle ergometer at an intensity of 50% VO2max. Training was undertaken for 3 days per week and maintained for 60 min per session. After training, physical and psychic symptoms determined by the Cornell Medical Index improved significantly. These results indicate that low physical work capacity in visually handicapped boys and young male adults is due to the lack of physical activity, and that mild endurance training is effective in improving physical and psychic symptoms as well as cardiorespiratory fitness.     

Effects of endurance moderate physical training on basal metabolism of young adult rats

In order to clarify the conclusion that the change of basal metabolism affected by physical training, effect of endurance training for 8 weeks on basal metabolism of young adult rats were investigated. Results are as follows. Endurance training increased significantly running ability of rats, for instance the running time at a speed of 25 m/min on the control and training groups were 53.7 +/- 18.8 min, 232.8 +/- 32.8 min, respectively. The ratio of soleus's weight to the body weight in trained rats was high significantly (p less than 0.05). The glycogen contents of trained rats under the condition of feeding have higher than the control rats. Especially, glycogen contents of the soleus and red-gastrocnemius significant increased (p less than 0.05), and liver glycogen content under the same condition increased significantly (p less than 0.02). The oxygen consumption in trained rats increased significantly compared with control rats (p less than 0.03). The basal metabolism of trained rats showed 1.24-fold increase compared with those of control (p less than 0.02). Oxygen consumption of sliced ventricle in trained rats increased significantly (p less than 0.03), it's rate was 118% of control. However those of other tissues did not change significantly.     

Plasma metabolic profile in COPD patients: effects of exercise and endurance training

The study examines plasma metabolic profiles of patients with chronic obstructive pulmonary disease (COPD) to prove whether the disease influences metabolism at rest and after endurance training. This is based on the hypothesis that metabolome levels should reflect impaired skeletal muscle bioenergetics in COPD. The study aims to test this hypothesis by evaluating plasma metabolic profiles in COPD patients before and after 8?weeks of endurance exercise training. We studied blood samples from 18 COPD patients and 12 healthy subjects. Pre- and post-training blood plasma samples at rest and after constant-work rate exercise (CWRE) at 70% of pre-training Watts peak were analyzed by ¹H-nuclear magnetic resonance spectroscopy to assess metabolite profiles. The two groups presented training-induced physiological changes in the VO₂ peak and in blood lactate levels (P?<?0.01 each). Before training, the two groups also showed differences in metabolic profiles at rest (P?<?0.05). Levels of valine (r?=?0.51, P?<?0.01), alanine (r?=?0.45, P?<?0.05) and isoleucine (r?=?0.51, P?<?0.01) were positively associated with body composition (Fat Free Mass Index). While training showed a significant impact on the metabolic profile in healthy subjects (P?<?0.001), with changes in levels of amino acids, creatine, succinate, pyruvate, glucose and lactate (P?<?0.05 each), no equivalent training-induced effects were seen in COPD patients in whom only lactate decreased (P?<?0.05). This study shows that plasma metabolic profiling contributes to the phenotypic characterization of COPD patients.     

Paradoxical effects of endurance training and chronic hypoxia on myofibrillar ATPase activity

This study aimed to determine the changes in soleus myofibrillar ATPase (m-ATPase) activity and myosin heavy chain (MHC) isoform expression after endurance training and/or chronic hypoxic exposure. Dark Agouti rats were randomly divided into four groups: control, normoxic sedentary (N; n = 14), normoxic endurance trained (NT; n = 14), hypoxic sedentary (H; n = 10), and hypoxic endurance trained (HT; n = 14). Rats lived and trained in normoxia at 760 mmHg (N and NT) or hypobaric hypoxia at 550 mmHg (approximately 2,800 m) (H and HT). m-ATPase activity was measured by rapid flow quench technique; myosin subunits were analyzed with mono- and two-dimensional gel electrophoresis. Endurance training significantly increased m-ATPase (P < 0.01), although an increase in MHC-I content occurred (P < 0.01). In spite of slow-to-fast transitions in MHC isoform distribution in chronic hypoxia (P < 0.05) no increase in m-ATPase was observed. The rate constants of m-ATPase were 0.0350 +/- 0.0023 s(-1) and 0.047 +/- 0.0050 s(-1) for N and NT and 0.033 +/- 0.0021 s(-1) and 0.038 +/- 0.0032 s(-1) for H and HT. Thus, dissociation between variations in m-ATPase and changes in MHC isoform expression was observed. Changes in fraction of active myosin heads, in myosin light chain isoform (MLC) distribution or in MLC phosphorylation, could not explain the variations in m-ATPase. Myosin posttranslational modifications or changes in other myofibrillar proteins may therefore be responsible for the observed variations in m-ATPase activity.     

Aging and respiratory muscle metabolic plasticity: effects of endurance training.

We examined the oxidative and antioxidant enzyme activities in respiratory and locomotor muscles in response to endurance training in young and aging rats. Young adult (4-mo-old) and old (24-mo-old) female Fischer 344 rats were divided into four groups: 1) young trained (n = 12), 2) young untrained (n = 12), 3) old trained (n = 10), and 4) old untrained (n = 6). Both young and old endurance-trained animals performed the same training protocol during 10 wk of continuous treadmill exercise (60 min/day, 5 days/wk). Compared with young untrained animals, the young trained group had significantly elevated (P less than 0.05) activities of 3-hydroxyacyl-CoA dehydrogenase (HADH), glutathione peroxidase (GPX), and citrate synthase (CS) in both the costal diaphragm and the plantaris muscle. In contrast, training had no influence (P greater than 0.05) on the activity of lactate dehydrogenase within the costal diaphragm in young animals. In the aging animals, training did not alter (P greater than 0.05) activities of CS, HADH, GPX, or lactate dehydrogenase in the costal diaphragm but significantly (P less than 0.05) increased CS, HADH, and GPX activities in the plantaris muscle. Furthermore, training resulted in higher activities of CS and HADH in the intercostal muscles in the old trained than in the old untrained animals. Finally, activities of CS, HADH, and GPX were significantly (P less than 0.05) lower in the plantaris in the old untrained than in the young untrained animals; however, CS, HADH, and GPX activities were greater (P less than 0.05) in the costal diaphragm in the old sedentary than in the young untrained animals.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effects of endurance training and thiamine supplementation on anti-fatigue during exercise

The purpose of this study was to find the effect of endurance training and thiamine supplementation on anti-fatigue during the exercise. Each nine students from K Women’s University went through three cross-over treatments: placebo treatment, training treatment and thiamine treatment. Training treatment was performed with bicycle ergometer exercise for four weeks (five days per week). Each exercise was performed for an hour with intensity set at 70% (50rpm) of maximal oxygen uptake. Thiamine treatment group was given 10mg of thiamine tetrahydrofurfuryl disulfide per one kilogram for four weeks. The bicycle ergometer exercise was performed at 70% of maximal oxygen uptake in exercise intensity which 60 minutes of exercise was performed at 50rpm . Lactate concentration was significantly decreased during 15 to 30 minutes of exercise for those with training treatment and 15 to 60 minutes of exercise for those with thiamine treatment compared to placebo treatment group. Ammonia concentration was significantly decreased during 15 to 60 minutes of exercise and 15 to 30 minutes of recovery for those with training and thiamine treatment compared to placebo treatment. Resting blood thiamine concentrations of placebo treatment were significantly lower than training treatment. 60 minutes after the exercise, plasma thiamine concentration was significantly increased in all treatment group. To sum up the previous, thiamine intake during exercise positively benefits carbohydrate metabolism in a way that will decrease lactate concentration, ammonia concentration, and anti- fatigue by reducing the RPE. Therefore, we can consider thiamine intake to be utilized as similar benefits as endurance training.     

Subsarcolemmal mitochondria and capillarization of soleus muscle fibers in young rats subjected to an endurance training

Summary Rats, 6 weeks old, were subjected to a program of endurance running for 3, 6 and 12 weeks. 0.5 to 0.8 m thick sections of Epon embedded soleus muscles were studied with morphometric methods.In cross-sections the area occupied by subsarcolemmal mitochondria was independent of the age, but was 53% higher after 12 weeks of training. The mean depth of the zones with subsarcolemmal mitochondria increased only 15% to about 0.9 m. Thus, the subsarcolemmal mitochondria showed a pronounced spreading at the muscle fiber surface in trained muscles. — The number of capillaries per fiber decreased slightly in controls and increased not significantly in trained muscles.It is concluded that the subsarcolemmal mitochondria supply the energy for the active transport of metabolites through the sarcolemma in oxidative muscle fibers, and that they are the limiting factor for endurance performance of the soleus muscle fibers because the changes in the capillarization were only small. It is suggested that the subsarcolemmal and the interfibrillar mitochondria have different functions and may therefore represent different types of mitochondria which can be distinguished by their morphology as well as by their biochemical properties.