Serum cortisol reduction and abnormal prolactin and CD4+/CD8+ T-cell response as a result of controlled exercise in patients with rheumatoid arthritis and systemic lupus erythematosus despite unaltered muscle energetics.
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OBJECTIVE: To investigate muscle energetics in patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) and measure serum cortisol, prolactin and CD4+/CD8+ T-cell levels during and after controlled exhaustive exercise. METHODS: Patients with RA (n = 7), patients with SLE (n = 6) and healthy individuals (HI) (n = 10) performed incremental cycle ergometry to the limit of tolerance. Ventilation, oxygen uptake (VO2) and carbon dioxide output were measured and the lactate threshold (LT) was estimated. Serum cortisol, prolactin, CD4+ and CD8+ lymphocyte subset levels were determined at baseline, peak exercise and 1 h after exercise. RESULTS: Exercise tolerance was reduced in patients with RA and patients with SLE, as reflected by peak VO2 and LT, but muscle energetics were not altered. In RA and SLE, there was significant reduction in cortisol levels at peak (-10%; P = 0.03) and post-exercise times (-36%; P = 0.05). Prolactin varied significantly at peak exercise in HI only (+60%; P = 0.05). There was a significant reduction in CD4+ T cells at peak exercise in RA (-15%; P = 0.02) and SLE patients (-8%; P = 0.04) and an increase after exercise in SLE patients (+11%; P = 0.03). In HI, CD8+ T cells increased significantly (+47%; P = 0.01) at peak exercise, but this was not found in RA and SLE patients. A significant reduction in CD8+ T cells was noted after exercise in SLE patients (-6%; P = 0.05). CONCLUSION: RA and lupus patients do not have significantly altered muscle energetics, but have abnormal cortisol, prolactin and CD4+/CD8+ T-cell responses to exercise. Further studies need to be carried out to evaluate whether short bouts of strenuous exercise have detrimental clinical effects. (+info)
Enhanced carotid-cardiac baroreflex response and elimination of orthostatic hypotension 24 hours after acute exercise in paraplegics.
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To test the hypothesis that an acute bout of maximal exercise can ameliorate orthostatic hypotension consequent to prolonged wheelchair confinement, we evaluated heart rate (HR), systolic (SBP) and diastolic (DBP) blood pressure responses during 15 minutes of 70 degrees head-up tilt (HUT) in 10 paraplegic subjects 24 hours after arm crank exercise designed to elicit maximal effort, and during a control (no exercise) conditions. Additionally, the carotid baroreceptor stimulus-cardiac response relationship was determined by measurement of R-R interval during external application of graded pressures to the carotid sinuses. One week separated the treatment conditions. The maximum slope of the carotid-cardiac baroreflex response was increased (p = 0.049) by exercise (6.2 +/- 1.7 msec/mmHg) compared to control (3.3 +/- 0.6). During control HUT, HR increased from 61 +/- 1 to 90 +/- 7 bpm (p = 0.001) while SBP decreased from 118 +/- 5 to 106 +/- 9 mmHg (p = 0.025). During HUT 24 hours after exercise, HR increased from 60 +/- 2 to 90 +/- 4 bpm (p = 0.001), but the reduction in SBP was essentially eliminated (116 +/- 5 to 113 +/- 5 mmHg). The reduction in SBP during control HUT (-12.0 +/- 4.6 mmHg) was four-fold larger (p = 0.017) than during HUT following exercise (-3.1 +/- 3.9 mmHg). DBP during HUT was not altered in either condition. A single bout of intense, dynamic arm crank exercise eliminated orthostatic hypotension in paraplegics. Equal HR response with smaller reduction in SBP during HUT after exercise was consistent with a measured increased sensitivity of the carotid-cardiac baroreflex.(ABSTRACT TRUNCATED AT 250 WORDS) (+info)
Whole body muscle hypertrophy from resistance training: distribution and total mass.
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OBJECTIVE: To examine the absolute and relative changes in skeletal muscle (SM) size using whole body magnetic resonance imaging (MRI) in response to heavy resistance training (RT). METHOD: Three young men trained three days a week for 16 weeks. RESULTS: MRI measured total SM mass and fat free mass (FFM) had increased by 4.2 kg and 2.6 kg respectively after resistance training. CONCLUSIONS: RT induces larger increases in SM mass than in FFM. RT induced muscle hypertrophy does not occur uniformly throughout each individual muscle or region of the body. Therefore the distribution of muscle hypertrophy and total SM mass are important for evaluating the effects of total body RT on muscle size. (+info)
Work related upper limb disorder: the relationship between pain, cumulative load, disability, and psychological factors.
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Repetitive strain injury, or work related upper limb disorder, provides an interesting paradigm for the study of the relative contribution of physical and psychological factors to the resulting pain and disability. Sixty three subjects were studied, comprising the work-force of a subsection of a large local industrial company, in whom pain in the arm related to work was known to be common. Ergonomic data were obtained by estimating the cumulative daily load on the wrist joint for each of four identified tasks. Data on the occurrence of pain, treatment sought, and disability were obtained by a structured self administered questionnaire. Psychological data were obtained by administering the Hospital Anxiety and Depression (HAD) scale, a self reported measure of anxiety and depression, and the Bradford Somatic Inventory (BSI), an inventory of somatic symptoms associated with anxiety and depression. The employment specific period prevalence of work related upper limb disorder was 81%, with 30% of the subjects having pain at the time of the study. Domestic disability was minimal in all but two subjects, though the use of devices such as jar openers at home was common (12 of 51 subjects). Medical advice was seldom sought. Twenty per cent of subjects had received anti-inflammatory drugs, 10% had received physiotherapy, and 47% had wrist splints. Pain was related to the tasks with the highest estimated daily loads, but a history of pain and current pain were associated with higher scores on the HAD and BSI scales, suggesting an interaction between physical and psychological factors. (+info)
Effects of body mass index on maximal work production capacity and aerobic fitness during incremental exercise.
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The aim of this study was to investigate the relationship between cardiopulmonary fitness as indicated by maximal work rate (Wmax) production and aerobic capacities (WAT), body mass index (BMI) and heart rate reserve. A total of 60 sedentary subjects (30 males, 30 females, aged 18-25 years) were enrolled in the study. Each subject performed an incremental exercise test (15 W/min) to the limit of tolerance on an electromagnetically-braked cycle ergometer. There was a negative correlation between increased BMI to Wmax capacity per kilogram body weight in male (r=-0.846, P=0.0001) and in female (r=-0.896, P=0.0001) subjects. In addition, W(AT) for each kilogram body weight also negatively correlated with increased BMI in male (r=-0.870, P=0.0001) and in females (r=-0.807, P=0.0001). The heart rate reserve correlated negatively with increasing BMI: r=-0.699, P=0.0001 (males) and r=-0.655, P=0.0001 (females). The results of the present study have suggested that, due to the inverse correlation between BMI, Wmax capacity, aerobic fitness and heart rate reserve, it may be useful to consider BMI in establishing cardiopulmonary fitness in various subjects. (+info)
Skeletal myocytes are a source of interleukin-6 mRNA expression and protein release during contraction: evidence of fiber type specificity.
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In this study, we aimed to determine whether skeletal muscle cells per se are a source of interleukin (IL)-6 during contraction and whether IL-6 production is fiber type specific. Muscle biopsy samples were collected from seven males before (PRE) and after (POST) completing 120 min of continuous bicycle ergometry. Biopsies were sectioned and analyzed for the following: IL-6 protein detected by immunohistochemistry (IHC), IL-6 mRNA content detected by in situ hybridization, fiber type measured by either IHC or myofibrillar ATPase activity stain, and glycogen content measured by periodic acid schiff (PAS) assay. Fibers were qualitatively categorized according to glycogen content to one of five groups (1-5), with 1 being very low (LOW) and 5 being very high (HIGH) glycogen. Total fluorescence (PRE vs. POST) and glycogen-dependent fluorescence (LOW vs. HIGH) of IL-6 protein were quantitated using Metamorph software. Total IL-6 protein was elevated from PRE to POST exercise (P<0.05). At PRE, IL-6 protein was evenly distributed across all fibers at low levels, consistent with glycogen distribution. At POST, IL-6 protein was greater (P<0.05) in HIGH compared with LOW glycogen fibers, which coincided with type 2 fibers. IL-6 mRNA was distributed peripherally in all fibers at PRE. At POST, however, IL-6 mRNA appeared predominantly in type 2 fibers, which also had higher glycogen content (P<0.05). These data demonstrate that myocytes per se are a source of IL-6 produced during contraction. Our data also suggest that type 2 fibers predominantly produce IL-6 during muscle contractile activity. (+info)
Is the Stresst'er a reliable stress test to detect mild to moderate peripheral arterial disease?
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BACKGROUND: A stress test is required in patients with a resting ankle brachial pressure index (ABPI) of >0.9 in whom peripheral arterial disease (PAD) is suspected. OBJECTIVE: To see if the Stresst'er Ergometer could mimic a standard 1 min treadmill exercise test and successfully diagnose the presence of significant PAD. METHODS: Legs with a resting ABPI >0.9, a positive exercise test and PAD confirmed on Duplex ultrasound, underwent various protocols on the Stresst'er Ergometer. The results were compared to control legs with no PAD (normal stress test). RESULTS: By making various adjustments to the rate and duration of the exercise, the resistance provided by the Stresst'er to the exercise and the timing of the post exercise ABPI measurement it was possible to accurately diagnose significant PAD. CONCLUSION: Using an appropriate protocol it is possible to use the Stresst'er Ergometer to assist in the diagnosis of significant PAD. Being a portable, space saving device, the Stresst'er offers the opportunity of diagnosis outside the vascular laboratory. This would facilitate medical therapy to at risk patients. (+info)
Differential expression of nitric oxide synthases (NOS 1-3) in human skeletal muscle following exercise countermeasure during 12 weeks of bed rest.
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Adaptive changes of major body systems in astronauts during spaceflight can be simulated by strict anti-orthostatic head-down tilt (HDT) bed rest (BR), a ground-based microgravity (microG) model that provides a meaningful opportunity to study atrophy mechanisms and possible countermeasures under controlled experimental conditions. As nitric oxide (NO) signaling is linked to muscle activity, we investigated altered expression of the three major isoforms of nitric oxide synthase (NOS 1-3) at cellular compartments during prolonged HDT BR without (control group) and with resistance exercise interventions (exercise group) using a flywheel ergometer (FWE). Atrophy detected in mixed (fast-slow) m. vastus lateralis (VL) and slow-type m. soleus (SOL) myofiber Types I and II (minus 35-40% of myofiber cross-sectional area) was prevented by FWE training. Concomitant to muscle atrophy, reduced NOS 1 protein and immunostaining was found in VL not in SOL biopsies. In trained VL, NOS 1 protein and immunostaining at myofibers II were significantly increased at the end of BR. Exercise altered NOS 2/caveolin 3 co-immunostaining patterns of subsarcolemmal focal accumulations in VL or SOL myofibers, which suggests reorganization of sarcolemmal microdomains. In trained VL, increased capillary-to-fiber (C/F) ratio and NOS 3 protein content were documented. Activity-linked NO signaling may be widespread in skeletal muscle cellular compartments that may be directly or indirectly impacted by adequate exercise countermeasure protocols to offset the negative effects induced by disuse, immobilization, or extended exposure to microgravity. (+info)