Enhanced concentrations of relevant markers of nitric oxide formation after exercise training in patients with metabolic syndrome

Metabolic syndrome (MetS) denotes a clustering of risk factors that may affect nitric oxide (NO) bioavailability and predispose to cardiovascular diseases, which are delayed by exercise training. However, no previous study has examined how MetS affects markers of NO formation, and whether exercise training increases NO formation in MetS patients. Here, we tested these two hypotheses. We studied 48 sedentary individuals: 20 healthy controls and 28 MetS patients. Eighteen MetS patients were subjected to a 3-month exercise training (E+group), while the remaining 10 MetS patients remained sedentary (E-group). The plasma concentrations of nitrite, cGMP, and ADMA (asymmetrical dimethylarginine: an endogenous nitric oxide synthase inhibitor), and the whole blood nitrite concentrations were determined at baseline and after exercise training using an ozone-based chemiluminescence assay, and commercial enzyme immunoassays. Thiobarbituric acid reactive species (TBA-RS) were measured in the plasma to assess oxidative stress using a fluorometric method. We found that, compared with healthy subjects, patients with MetS have lower concentrations of markers of NO formation, including whole blood nitrite, plasma nitrite, and plasma cGMP, and increased oxidative stress (all P < 0.05). Exercise training increased the concentrations of whole blood nitrite and cGMP, and decreased both oxidative stress and the circulating concentrations of ADMA (both P < 0.05). These findings show clinical evidence for lower endogenous NO formation in patients with MetS, and for improvements in NO formation associated with exercise training in MetS patients. (C) 2008 Elsevier Inc. All rights reserved.

Nitric oxide inhibition in paraventricular nucleus on cardiovascular and autonomic modulation after exercise training in unanesthetized rats

It is well known that regular physical exercise alter cardiac function and autonomic modulation of heart rate variability (HRV). The paraventricular nucleus of hypothalamus (PVN) is an important site of integration for autonomic and cardiovascular responses, where nitric oxide (NO) plays an important role. The aim of our study was to evaluate the cardiovascular parameters and autonomic modulation by means of spectral analysis after nitric oxide synthase (NOS) inhibition in the PVN in conscious sedentary (S) or swimming trained (ST) rats. After swimming training protocol, adult male Wistar rats, instrumented with guide cannulas to PVN and femoral artery and vein catheters were submitted to mean arterial pressure (MAP) and heart rate (HR) recording. At baseline, the physical training induced a resting bradycardia (S: 374 +/- 5, ST: 346 +/- 1 bpm) and promoted adaptations in HRV characterized by an increase in high-frequency oscillations (HF; 26.43 +/- 6.91 to 88.96 +/- 244) and a decrease in low-frequency oscillations (LF; 73.57 +/- 6.91 to 11.04 +/- 2.44) in normalized units. The microinjection of N(omega)-nitro-L-arginine methyl ester (L-NAME) in the PVN of sedentary and trained rats promoted increase in MAP and HR. L-NAME in the PVN did not significantly alter the spectral parameters of HRV of sedentary animals, however in the trained rats increased LF oscillations (11.04 +/- 2.44 to 27.62 +/- 6.97) and decreased HF oscillations (88.96 +/- 2.44 to 72.38 +/- 6.97) in normalized units compared with baseline. Our results suggest that NO in the PVN may collaborate to cardiac autonomic modulation after exercise training. (c) 2010 Elsevier B.V. All rights reserved.

Morphological comparison of different protocols of skeletal muscle remobilization in rats after hindlimb suspension

The aim of this study was to evaluate and compare the efficacy of different remobilization protocols in different skeletal muscles considering the changes induced by hindlimb suspension of the tail. Thirty-six female Wistar rats were divided into six groups: control I, control II, suspended, suspended free, suspended trained on a declined treadmill and suspended trained on a flat treadmill. Fragments of soleus and tibialis anterior (TA) muscle were frozen and processed by different histochemical methods. The suspended soleus showed a significant increase in the proportional number of intermediate/hybrid fibers and a decrease in the number of type I fibers. Some of these changes proved to be reversible after remobilization. The three remobilization programs led to the recovery of both the proportional number of fibers and their size. The TA muscle presented a significant increase in the number and size of type I fibers and a cell size reduction of type IIB fibers, which were recovered after training on a declined treadmill and free movement. Especially regarding the soleus, the present findings indicate that, among the protocols, training on a declined treadmill was found to induce changes of a more regenerative nature, seemingly indicating a better tissue restructuring after the suspension procedure.

Effects of eccentric and concentric training on capillarization and myosin heavy chain contents in rat skeletal muscles after hindlimb suspension

We studied the effects of different protocols of post-disuse rehabilitation on angiogenesis and myosin heavy chain (MHC) content in rat hindlimb muscles after caudal suspension. Thirty female Wistar rats were divided into five groups: (1) Control I, (2) Control II, (3) Suspended, (4) Suspended trained on declined treadmill, and (5) Suspended trained on flat treadmill. Fragments of the soleus and tibialis anterior (TA) muscles were frozen and processed by electrophoresis and immunohistochemistry (CD31 antibody). Hindlimb suspension caused reduction of capillary/fiber (C/F) ratios and contents of MHC type I (MHCI) in the soleus in parallel to increased capillary density. Flat treadmill protocols increased the content of the MHCI isoform. The C/F ratio was increased by concentric training after hypokinesis, but was not modified by eccentric training, which caused a greater reduction of capillary density compared to the other protocols. In the TA muscle, hindlimb suspension caused a non-significant increase in capillary density and C/F ratio with limited changes in MHC. The present data demonstrate that the different training protocols adopted and the functional performance of the muscles analyzed caused specific changes in capillarization and in the content of the various MHC types. (C) 2010 Published by Elsevier GmbH.

Exercise reduces inflammation and cell proliferation in rat colon carcinogenesis

Purposes: There is evidence that the risk of colon cancer is reduced by appropriate levels of physical exercise. Nevertheless, the mechanisms involved in this protective effect of exercise remain largely unknown. Inflammation is emerging as a unifying link between a range of environment exposures and neoplastic risk. The carcinogen dimethyl-hydrazine (DMH) induces an increase in epithelial cell proliferation and in the expression of the inflammation-related enzyme cyclooxigenase-2 (COX-2) in the colon of rats. Our aim was to verify whether these events could be attenuated by exercise. Methods: Four groups of eight Wistar rats were used in the experiment. The groups G1 and G3 were sedentary (controls), and the groups G2 and G4 were submitted to 8 wk of swimming training, 5 d wk(-1). The groups G3 and G4 were given subcutaneous injections of DMH immediately after the exercise protocols. Fifteen days after the neoplasic induction, the rats were sacrificed and the colon was processed for histological examination and immunohistochemistry staining of proliferating cell nuclear antigen (PCNA) and COX-2. Results: We found a significant increase in the PCNA-labeling index in both DMH-treated groups of rats. However, this increase was significantly attenuated in the training group G4 (P < 0.01). Similar results were observed in relation to the COX-2 expression. Conclusions: From our findings, we conclude that exercise training exerts remarkable antiproliferative and antiinflammatory effects in the rat colonic mucosa, suggesting that this may be an important mechanism to explain how exercise protects against colonic cancer.

Effect of Acute and Chronic Physical Exercise on Patients with Periodic Leg Movements

ESTEVES, A. M., M. T. DE MELLO, M. PRADELLA-HALLINAN, and S. TUFIK. Effect of Acute and Chronic Physical Exercise on Patients with Periodic Leg Movements. Med. Sci. Sports Exerc., Vol. 41, No. 1,. pp. 237-242, 2009. Purpose: Nonpharmacological interventions may lead to an improvement in sleep quality. The objective of our study was to evaluate the effects of acute intensive exercise and chronic exercise on sleep patterns in patients with periodic leg movements (PLM). Methods: The study involved acute and chronic exercise. The acute intensive exercise group consisted of 22 volunteers who underwent a maximum effort test and a polysomnography (PSG) on the same night. The chronic exercise group included. 11 patients who performed 72 physical training sessions undergoing three PSG studies on the night of sessions 1, 36, and 72. Blood samples were collected from both acute and chronic groups for beta-endorphin dosage. Results: Our results showed that both forms of physical exercise lowered PLM levels. The acute physical exercise increased sleep efficiency, rapid eye movement (REM) sleep, and reduced wake after sleep onset, whereas the chronic physical exercise increased sleep efficiency, REM sleep, and reduced sleep latency. We also found a significant negative correlation between beta-endorphin release after acute intensive exercise and PLM levels (r = -0.63). Conclusion: Physical exercise may improve sleep patterns and reduce PLM levels. The correlation between beta-endorphin release after acute intensive exercise and PLM levels might be associated with the impact physical exercise has on the opiodergic system. We suggest that physical exercise may be a useful nonpharmacological treatment for PLM.

Effects of progressive exercise during phase I cardiac rehabilitation on the heart rate variability of patients with acute myocardial infarction

Purpose. aEuro integral Heart rate variability (HRV) decreases after an acute myocardial infarction (AMI) due to changes in cardiac autonomic balance. The purpose of the present study, therefore, was to evaluate the effects of a progressive exercise protocol used in phase I cardiac rehabilitation on the HRV of patients with post-AMI. Material and methods. aEuro integral Thirty-seven patients who had been admitted to hospital with their first non-complicated AMI were studied. The treated group (TG, n == 21, age == 52 +/-+/- 12 years) performed a 5-day programme of progressive exercise during phase I cardiac rehabilitation, while the control group (CG, n == 16, age == 54 +/-+/- 11 years) performed only respiratory exercises. Instantaneous heart rate (HR) and RR interval were acquired by a HR monitor (Polar (R) A (R) S810i). HRV was analysed by frequency domain methods. Power spectral density was expressed as normalised units (nu) at low (LF) and high (HF) frequencies, and as LF/HF. Results. aEuro integral After 5 days of progressive exercise, the TG showed an increase in HFnu (35.9 +/-+/- 19.5 to 65.19 +/-+/- 25.4) and a decrease in LFnu and LF/HF (58.9 +/-+/- 21.4 to 32.5 +/-+/- 24.1; 3.12 +/-+/- 4.0 to 1.0 +/-+/- 1.5, respectively) in the resting position (p < 0.05). No changes were observed in the CG. Conclusions. aEuro integral A progressive physiotherapeutic exercise programme carried out during phase I cardiac rehabilitation, as supplement to clinical treatment increased vagal and decreased sympathetic cardiac modulation in patients with post-AMI.

Effects of Ipratropium on Exercise-Induced Bronchospasm

Exercise-induced bronchospasm (EIB) is the transient narrowing of the airways that follows vigorous exercise. Ipratropium bromide may be used to prevent EIB, but its effect varies among individuals. We hypothesized that time of administration of ipratropium interferes with its action. This was a prospective, double-blind, cross-over study carried out to evaluate the bronchoprotective and bronchodilatory effect of ipratropium at different times of day. The study consisted of 4 exercise challenge tests (2 at 7 am and 2 at 6 pm). In the morning, one of the tests was performed after placebo administration and the other one after ipratropium (80 mu g) and the two tests (placebo and ipratropium) were repeated in the evening. Twenty-one patients with severe or moderate asthma and previous confirmation of EIB were enrolled in this prospective trial. The bronchodilatory effect of ipratropium was 0.25 +/- 0.21 L or 13.11 +/- 10.99 % (p = 0.001 compared to baseline values) in the morning, and 0.14 +/- 0.25 L or 7.25 +/- 11.37 % (p > 0.05) in the evening. In the morning, EIB was 0.58 +/- 0.29 L on the placebo day and 0.38 +/- 0.22 L on the treatment day (p = 0.01). In the evening, EIB was 0.62 +/- 0.28 L on the placebo day and 0.51 +/- 0.35 L on the treatment day (p > 0.05). We suggest that the use of ipratropium for the treatment of asthma and EIB should take into consideration the time of administration.

Exercise training accelerates the removal from plasma of LDL-like nanoemulsion in moderately hypercholesterolemic subjects

Objective: Exercise training improves plasma lipid profile and diminishes risk of coronary heart disease. Previously, we showed that training increases LDL plasma clearance, as tested by an artificial LDL-like nanoemulsion method, presumably by increasing LDL receptor activity. In this study, we investigated whether training could also improve LDL clearance in hypercholesterolemic subjects (HCh) that are exposed to increased risk of cardiovascular events. Methods: Twenty sedentary HCh and 20 normolipidemic (NL) sedentary volunteers were divided into four groups: 12 HCh submitted to 4-month training program, 8 HCh with no exercise program, 12 NL submitted to 4-month training and 8 NL with no exercise program. An LDL-like nanoemulsion labeled with 14C-cholesteryl ester was injected intravenously into all subjects and plasma samples were collected during 24h after injection to determine the fractional clearance rate (FCR, in h-1) by compartmental analysis. The study was performed on the first and on the last day of the 4-month study period. Results: In both, trained HCh and NL groups, training increased nanoemulsion FCR by 36% (0.0443 +/- 0.0126; 0.0602 +/- 0.0187, p=0.0187 and 0.0503 +/- 0.0203; 0.0686 +/- 0.0216, p=0.0827, respectively). After training, LDL cholesterol diminished in both HCh and NL groups. In HCh, but not in NL group, LDL susceptibility to oxidation decreased, but oxidized LDL was unchanged. In both non-trained groups FCR was the same for the last and the 4-month previous evaluation. Conclusion: In HCh, exercise training increased the removal of LDL as tested by the nanoemulsion, and this probably accounted for decreased LDL cholesterol and diminished LDL susceptibility to oxidation. (C) 2010 Elsevier Ireland Ltd. All rights reserved.

The response of molecular isoforms of growth hormone to acute exercise in trained adult males

Circulating GH consists of multiple molecular isoforms, all derived from the one gene in nonpregnant humans. To assess the effect of a potent stimulus to pituitary secretion on GH isoforms, we studied 17 aerobically trained males (age, 26.9 +/- 1.5 yr) in a randomized, repeat measures study of rest vs. exercise. Exercise consisted of continuous cycle ergometry at approximately 80% of predetermined maximal oxygen uptake for 20 min. Serum was assayed for total, pituitary, 22-kDa, recombinant, non-22-kDa, 20-kDa, and immunofunctional GH. All isoforms increased during, peaked at the end, and declined after exercise. At peak exercise, 22-kDa GH was the predominant isoform. After exercise, the ratios of non-22 kDa/total GH and 20-kDa GH/total GH increased and those of recombinant/pituitary GH decreased. The disappearance half-times for pituitary GH and 20-kDa GH were significantly longer than those for all other isoforms. We conclude that 1) all molecular isoforms of GH measured increased with and peaked at the end of acute exercise, with 22-kBa GH constituting the major isoform in serum during exercise; and 2) the proportion of non-22-kDa isoforms increased after exercise due in part to slower disappearance rates of 20-kDa and perhaps other non-22-kDa GH isoforms. It remains to be determined whether the various biological actions of different GH isoforms impact on postexercise homeostasis.

Fluid shifts resulting from exercise in rats as detected by bioelectrical impedance

Purpose: This study was designed to investigate the immediate effect of exercise intensity and duration on body fluid volumes in rats throughout a 3-wk exercise program. Methods: Changes in the extracellular water (ECW) and total body water (TBW) volumes of rats were measured preexercise and postexercise using multiple frequency bioelectrical impedance analysis. Groups of rats were exercised at two intensities (6 m.min(-1) and 12 m.min(-1)) for two exercise times (60 min and 90 min) 5 d.wk(-1) during a 3-wk period. Changes in plasma electrolytes, glucose, and lactate resulting from the exercise were also measured on 3 d of each week. Results: Each group of animals showed significant losses in ECW and TBW as a direct result of daily exercise. The magnitude of fluid loss was directly related to the intensity of the exercise, bur not to exercise duration; although the magnitude of daily fluid loss at the higher intensity exercise (12 m.min(-1)) decreased as the study progressed, possibly indicating a training effect. Conclusion: At low-intensity exercise, there is a small bur significant loss in both TBW and ECW fluids, and the magnitude of these losses does not change throughout a 3-wk exercise program. At moderate levels of exercise intensity, there is a greater loss of both TBW and ECW fluids. However, the magnitudes of these losses decrease significantly during the 3-wk exercise program, thus demonstrating a training effect.

Too wet to exercise? Leaking urine as a barrier to physical activity in women

Leaking urine Is frequently mentioned (anecdotally) by women as a barrier to physical activity. The aim of this paper was to use results from the Australian Longitudinal Study on Women's Health (ALSWH) to explore the prevalence of leaking urine in Australian women, and to ascertain whether leaking urine might be a barrier to participation for women. More than 41,000 women participated in the baseline surveys of the ALSWH in 1996. More than one third of the mid-age (45-50 years) and older (70-75) women and 13% of the young women (18-23) reported leaking urine. There was a cross-sectional association between leaking urine and physical activity, such that women with more frequent urinary leakage were also more likely to report low levels of physical activity. More than one thousand of those who reported leaking urine at baseline participated in a follow-up study in 1999. Of these, more than 40% of the mid-age women (who were aged 48-53 in 1999), and one in seven of the younger (21-26 years) and older (73-79 years) women reported leaking urine during sport or exercise. More than one third of the mid-age women and more than one quarter of the older women, but only 7% of the younger women said they avoided sporting activities because of leaking urine. The data are highly suggestive that leaking urine may be a barrier to physical activity, especially among mid-age women. As current estimates suggest that fewer than half of all Australian women are adequately active for health benefit, health professionals could be more proactive in raising this issue with women and offering help through non-invasive strategies such as pelvic floor muscle exercises.

The influence of diet and exercise on muscle and plasma glutamine concentrations

Purpose: This study examined the relationship between muscle glutamine, muscle glycogen, and plasma glutamine concentrations over 3 d of high-intensity exercise during which dietary carbohydrate (CHO) intake varied. Methods: Five endurance-trained men completed two exercise trials in randomized order, over a 14-d period. Each trial required subjects to perform 50 min of high-intensity continuous and interval exercise on three consecutive days while consuming a diet that provided 45% of the energy as CHO or a diet in which CHO provided 70% of the total energy. Four days of inactivity and consumption of a 55% CHO diet separated the two randomized trials. Menus and food were provided for the subjects and all food and drink consumed were weighed and recorded for later analysis. Before exercise on the first day of each trial, at the start of exercise on day 3 and on completion of exercise on day 3, muscle was biopsied from the vastus lateralis for the analysis of glutamine and glycogen concentrations. Venous blood was sampled before and twice after exercise on each day for the analysis of plasma glutamine and cortisol concentrations. Results: Mean plasma glutamine concentration was significantly higher during the 70% CHO exercise trial when compared with the 45% CHO trial (P < 0.05). Glycogen decreased by the same magnitude during both trials and there was no relationship between changes in plasma glutamine and changes in muscle glycogen concentration. Muscle glutamine concentration did not change in either trial. Conclusions: These data suggest that the influence of carbohydrate intake upon the concentration of plasma glutamine is not mediated through the concentration of intramuscular glycogen.