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Exercise Protocol (exercise + protocol)
Selected AbstractsImmediate Benefits of a Brief 10-Minute Exercise Protocol in a Chronic Pain Population: A Pilot StudyPAIN MEDICINE, Issue 4 2010Amy Burleson Sullivan PsyD Abstract Objective., Determining the acute effects of a brief, 10-minute exercise protocol on pain, mood, and perceived exertion. Patients., Twenty-eight subjects who were admitted to the Cleveland Clinic Chronic Pain Rehabilitation Program (CPRP), and who were capable of completing an experimenter-designed and controlled treadmill protocol were included in this pilot study. Methods., A within-group repeated measure analysis was used to compare 28 subjects admitted to the Cleveland Clinic CPRP. Measures of heart rate were obtained using the Nellcor Oximax, pulse oximeter; measures of mood and pain were obtained using a 0,10 Likert scale, and perceived exertion measured with a visual analog scale. Each measure was taken pre- and post-10-minute exercise protocol. Results., The brief exercise protocol was associated with self-report of immediate antidepressant and anxiolytic effects. Additionally, after the 3-week CPRP, self-reports in perceived exertion decreased. Brief exercise was not found to have an acute analgesic effect. Conclusion., This preliminary research revealed a temporal association of improvement in self-rated anxiety and depression, following a brief exercise protocol, and over the course of 3 weeks leads to decreased perceived exertion. Therefore suggesting that brief exercise is a safe, nonpharmacologic strategy for immediately improving mood, and has further implications for mortality risk. [source] Economy of locomotion in high-altitude Tibetan migrants exposed to normoxiaTHE JOURNAL OF PHYSIOLOGY, Issue 2 2005Claudio Marconi High-altitude Tibetans undergo a pattern of adaptations to chronic hypoxia characterized, among others, by a more efficient aerobic performance compared with acclimatized lowlanders. To test whether such changes may persist upon descent to moderate altitude, oxygen uptake of 17 male Tibetan natives lifelong residents at 3500,4500 m was assessed within 1 month upon migration to 1300 m. Exercise protocols were: 5 min treadmill walking at 6 km h,1 on increasing inclines from +5 to +15% and 5 min running at 10 km h,1 on a +5% grade. The data (mean ±s.e.m.) were compared with those obtained on Nepali lowlanders. When walking on +10, +12.5 and +15% inclines, net of Tibetans was 25.2 ± 0.7, 29.1 ± 1.1 and 31.3 ± 0.9 ml kg,1 min,1, respectively, i.e. 8, 10 and 13% less (P < 0.05) than that of Nepali. At the end of the heaviest load, blood lactate concentration was lower in Tibetans than in Nepali (6.0 ± 0.9 versus 8.9 ± 0.6 mm; P < 0.05). During running, of Tibetans was 35.1 ± 0.8 versus 39.3 ± 0.7 ml kg,1 min,1 (i.e. 11% less; P < 0.01). In conclusion, during submaximal walking and running at 1300 m, Tibetans are still characterized by lower aerobic energy expenditure than control subjects that is not accounted for by differences in mechanical power output and/or compensated for by anaerobic glycolysis. These findings indicate that chronic hypoxia induces metabolic adaptations whose underlying mechanisms still need to be elucidated, that persist for at least 1 month upon descent to moderate altitude. [source] Acute exercise reverses TRB3 expression in the skeletal muscle and ameliorates whole body insulin sensitivity in diabetic miceACTA PHYSIOLOGICA, Issue 1 2010A. Matos Abstract Aim:, TRB3 became of major interest in diabetes research when it was shown to interact with and inhibit the activity of Akt. Conversely, physical exercise has been linked to improved glucose homeostasis. Thus, the current study was designed to investigate the effects of acute exercise on TRB3 expression and whole body insulin sensitivity in obese diabetic mice. Methods:, Male leptin-deficient (ob/ob) mice swam for two 3-h-long bouts, separated by a 45-min rest period. After the second bout of exercise, food was withdrawn 6 h before antibody analysis. Eight hours after the exercise protocol, the mice were submitted to an insulin tolerance test (ITT). Gastrocnemius muscle samples were evaluated for insulin receptor (IR) and IRS-1 tyrosine phosphorylation, Akt serine phosphorylation, TRB3/Akt association and membrane GLUT4 expression. Results:, Western blot analysis showed that TRB3 expression was reduced in the gastrocnemius of leptin-deficient (ob/ob) mice submitted to exercise when compared with respective ob/ob mice at rest. In parallel, there was an increase in the insulin-signalling pathway in skeletal muscle from leptin-deficient mice after exercise. Furthermore, the GLUT4 membrane expression was increased in the muscle after the exercise protocol. Finally, a single session of exercise improved the glucose disappearance (KITT) rate in ob/ob mice. Conclusion:, Our results demonstrate that acute exercise reverses TRB3 expression and insulin signalling restoration in muscle. Thus, these results provide new insights into the mechanism by which physical activity ameliorates whole body insulin sensitivity in type 2 diabetes. [source] Influence of concurrent exercise or nutrition countermeasures on thigh and calf muscle size and function during 60 days of bed rest in womenACTA PHYSIOLOGICA, Issue 2 2007T. A. Trappe Abstract Aim:, The goal of this investigation was to test specific exercise and nutrition countermeasures to lower limb skeletal muscle volume and strength losses during 60 days of simulated weightlessness (6° head-down-tilt bed rest). Methods:, Twenty-four women underwent bed rest only (BR, n = 8), bed rest and a concurrent exercise training countermeasure (thigh and calf resistance training and aerobic treadmill training; BRE, n = 8), or bed rest and a nutrition countermeasure (a leucine-enriched high protein diet; BRN, n = 8). Results:, Thigh (quadriceps femoris) muscle volume was decreased (P < 0.05) in BR (,21 ± 1%) and BRN (,24 ± 2%), with BRN losing more (P < 0.05) than BR. BRE maintained (P > 0.05) thigh muscle volume. Calf (triceps surae) muscle volume was decreased (P < 0.05) to a similar extent (P > 0.05) in BR (,29 ± 1%) and BRN (,28 ± 1%), and this decrease was attenuated (P < 0.05) in BRE (,8 ± 2%). BR and BRN experienced large (P < 0.05) and similar (P > 0.05) decreases in isometric and dynamic (concentric force, eccentric force, power and work) muscle strength for supine squat (,19 to ,33%) and calf press (,26 to ,46%). BRE maintained (P > 0.05) or increased (P < 0.05) all measures of muscle strength. Conclusion:, The nutrition countermeasure was not effective in offsetting lower limb muscle volume or strength loss, and actually promoted thigh muscle volume loss. The concurrent aerobic and resistance exercise protocol was effective at preventing thigh muscle volume loss, and thigh and calf muscle strength loss. While the exercise protocol offset ,75% of the calf muscle volume loss, modification of this regimen is needed. [source] Prevalence of silent myocardial ischaemia in new-onset middle-aged Type 2 diabetic patients without other cardiovascular risk factorsDIABETIC MEDICINE, Issue 7 2006P. Fornengo Abstract Aims Coronary artery disease (CAD) is the leading cause of death in patients with Type 2 diabetes and is often asymptomatic. Silent myocardial ischaemia (SMI) is frequent in diabetic subjects and is responsible for a late diagnosis of CAD; its early detection is important. There are some data about the prevalence of SMI in Type 2 diabetic patients at high risk for cardiovascular disease, while no data are available in subjects at the onset of diabetes without other cardiovascular risk factors. Methods We screened 274 consecutive patients (mean age 64.3 ± 8.4 years, 66% male) at the time of diagnosis of Type 2 diabetes; we enrolled 111 subjects without other cardiovascular disease risk factors (dyslipidaemia, hypertension, peripheral vascular disease, retinopathy, microalbuminuria, history of heart disease) and with normal resting electrocardiogram (ECG). Participants performed a maximal ECG exercise protocol and, if positive, underwent coronary angiography. Results The ECG exercise test was positive in 19 patients (17.1%); of those 14 (13%) had angiographic coronary disease (one with three-vessel disease, three with two vessels and 10 with one vessel involved). The positive predictive value of the exercise ECG for predicting angiographic coronary disease was 73%. Conclusions The prevalence of SMI was 17% and angiographic coronary disease was found in 13% of middle-aged subjects with new-onset Type 2 diabetes without other cardiovascular risk factors. This prevalence is similar to that observed in studies of subjects with long duration diabetes who have additional cardiovascular risk factors. [source] Retraining cervical joint position sense: The effect of two exercise regimesJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 3 2007Gwendolen Jull Abstract This study compared the effects of conventional proprioceptive training and craniocervical flexion (C-CF) training on cervical joint position error (JPE) in people with persistent neck pain. The aim was to evaluate whether proprioceptive training was superior in improving proprioceptive acuity compared to another form of exercise, which has been shown to be effective in reducing neck pain. This may help to differentiate the mechanisms of effect of such interventions. Sixty-four female subjects with persistent neck pain and deficits in JPE were randomized into two exercise groups: proprioceptive training or C-CF training. Exercise regimes were conducted over a 6-week period, and all patients received personal instruction by an experienced physiotherapist once per week. A significant pre- to postintervention decrease in JPE, neck pain intensity, and perceived disability was identified for both the proprioceptive training group (p,<,0.001) and the C-CF training group (p,<,0.05). Patients who participated in the proprioceptive training demonstrated a greater reduction in JPE from right rotation compared to the C-CF training group (p,<,0.05). No other significant differences were observed between the two groups. The results demonstrated that both proprioceptive training and C-CF training have a demonstrable benefit on impaired cervical JPE in people with neck pain, with marginally more benefit gained from proprioceptive training. The results suggest that improved proprioceptive acuity following intervention with either exercise protocol may occur through an improved quality of cervical afferent input or by addressing input through direct training of relocation sense. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 2007 [source] Standardized protocol for a depletion of intramyocellular lipids (IMCL)NMR IN BIOMEDICINE, Issue 5 2010Michael Ith Abstract Intramyocellular lipids (IMCL) are flexible fuel stores that are depleted by physical exercise and replenished by fat intake. IMCL or their degradation products are thought to interfere with insulin signaling thereby contributing to insulin resistance. From a practical point of view it is desirable to deplete IMCL prior to replenishing them. So far, it is not clear for how long and at which intensity subjects have to exercise in order to deplete IMCL. We therefore aimed at developing a standardized exercise protocol that is applicable to subjects over a broad range of exercise capacity and insulin sensitivity and allows measuring reliably reduced IMCL levels. Twelve male subjects, including four diabetes type 2 patients, with wide ranges of exercise capacity (VO2peak per total body weight 27.9,55.8,ml*kg,1*min,1), insulin sensitivity (glucose infusion rate per lean body mass 4.7,15.3,mg*min,1*kg,1), and BMI (21.7,31.5,kg*m,2), respectively, were enrolled. Using 1H magnetic resonance spectroscopy (1H-MRS), IMCL was measured in m.tibialis anterior and m.vastus intermedius before and during a depletion protocol of a week, consisting of a moderate additional physical activity (1,h daily at 60% VO2peak) and modest low-fat (10,15%) diet. Absolute IMCL-levels were significantly reduced in both muscles during the first 3 days and stayed constant for the next 3 days of an identical diet/exercise-scheme. These reduced IMCL levels were independent of insulin sensitivity, yet a tendency to lower depleted IMCL levels has been observed in subjects with higher VO2peak. The proposed protocol is feasible in subjects with large differences in exercise capacity, insulin sensitivity, and BMI, leading to reduced IMCL levels that neither depend on the exact duration of the depletion protocol nor on insulin sensitivity. This allows for a standardized preparation of IMCL levels either for correlation with other physiological parameters or for replenishment studies. Copyright © 2010 John Wiley & Sons, Ltd. [source] Immediate Benefits of a Brief 10-Minute Exercise Protocol in a Chronic Pain Population: A Pilot StudyPAIN MEDICINE, Issue 4 2010Amy Burleson Sullivan PsyD Abstract Objective., Determining the acute effects of a brief, 10-minute exercise protocol on pain, mood, and perceived exertion. Patients., Twenty-eight subjects who were admitted to the Cleveland Clinic Chronic Pain Rehabilitation Program (CPRP), and who were capable of completing an experimenter-designed and controlled treadmill protocol were included in this pilot study. Methods., A within-group repeated measure analysis was used to compare 28 subjects admitted to the Cleveland Clinic CPRP. Measures of heart rate were obtained using the Nellcor Oximax, pulse oximeter; measures of mood and pain were obtained using a 0,10 Likert scale, and perceived exertion measured with a visual analog scale. Each measure was taken pre- and post-10-minute exercise protocol. Results., The brief exercise protocol was associated with self-report of immediate antidepressant and anxiolytic effects. Additionally, after the 3-week CPRP, self-reports in perceived exertion decreased. Brief exercise was not found to have an acute analgesic effect. Conclusion., This preliminary research revealed a temporal association of improvement in self-rated anxiety and depression, following a brief exercise protocol, and over the course of 3 weeks leads to decreased perceived exertion. Therefore suggesting that brief exercise is a safe, nonpharmacologic strategy for immediately improving mood, and has further implications for mortality risk. [source] Physical fitness indices and anthropometrics profiles in schoolchildren with sickle cell trait/diseaseAMERICAN JOURNAL OF HEMATOLOGY, Issue 2 2007Hisham Moheeb Abstract The current studies aimed at determining physical fitness indices and anthropometrics profiles of school children with sickle cell trait (SCT) and sickle cell disease (SCD). Male school children (150) comprising 3 Groups participated in the studies. Group 1 has 50 normal healthy controls, while Groups 2 and 3 each has 50 children who were suffering from SCT and SCD, respectively. Anthropometrics measurement and parameters of physical fitness were assessed in all subjects. All children were also subjected to a 5-min running exercise test on a flat motorized treadmill at speed corresponding to 5 km/hr. Throughout the test, heart rate was monitored and recoded during exercise and for 10-min during recovery. Blood lactate was measured before and 5 min following the completion of test. The mean values of lean body mass and height were lower in the SCD children (P < 0.05) compared with the healthy subjects and SCT individuals. Children with SCD exhibited a higher mean value (P < 0.05) for percent body fat and fat mass than the normal healthy subjects and SCT individuals. Although all groups tolerated well the treadmill exercise protocol, the SCD group exhibited higher (P < 0.05) mean values of heart rate during exercise than those observed in the SCT and normal control children. In addition, SCD children showed higher serum lactate values before and after treadmill exercise compared to the other groups. Children with SCD exhibit high level of adiposity; low level of fitness and their exercise performance appears to be physiologically more stressful as indicated by heart rate and blood lactate concentration responses. Am. J. Hematol., 2006. © 2006 Wiley-Liss, Inc. [source] Acute exercise modulates the Foxo1/PGC-1, pathway in the liver of diet-induced obesity ratsTHE JOURNAL OF PHYSIOLOGY, Issue 9 2009Eduardo R. Ropelle PGC-1, expression is a tissue-specific regulatory feature that is extremely relevant to diabetes. Several studies have shown that PGC-1, activity is atypically activated in the liver of diabetic rodents and contributes to hepatic glucose production. PGC-1, and Foxo1 can physically interact with one another and represent an important signal transduction pathway that governs the synthesis of glucose in the liver. However, the effect of physical activity on PGC-1,/Foxo1 association is unknown. Here we investigate the expression of PGC-1, and the association of PGC-1,/Foxo1 in the liver of diet-induced obese rats after acute exercise. Wistar rats swam for two 3 h-long bouts, separated by a 45 min rest period. Eight hours after the acute exercise protocol, the rats were submitted to an insulin tolerance test (ITT) and biochemical and molecular analysis. Results demonstrate that acute exercise improved insulin signalling, increasing insulin-stimulated Akt and Foxo1 phosphorylation and decreasing PGC-1, expression and PGC-1,/Foxo1 interaction in the liver of diet-induced obesity rats under fasting conditions. These phenomena are accompanied by a reduction in the expression of gluconeogenesis genes, such as phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphate (G6Pase). Thus, these results provide new insights into the mechanism by which exercise could improve fasting hyperglycaemia. [source] Acute physical exercise reverses S -nitrosation of the insulin receptor, insulin receptor substrate 1 and protein kinase B/Akt in diet-induced obese Wistar ratsTHE JOURNAL OF PHYSIOLOGY, Issue 2 2008José R. Pauli Early evidence demonstrates that exogenous nitric oxide (NO) and the NO produced by inducible nitric oxide synthase (iNOS) can induce insulin resistance. Here, we investigated whether this insulin resistance, mediated by S -nitrosation of proteins involved in early steps of the insulin signal transduction pathway, could be reversed by acute physical exercise. Rats on a high-fat diet were subjected to swimming for two 3 h-long bouts, separated by a 45 min rest period. Two or 16 h after the exercise protocol the rats were killed and proteins from the insulin signalling pathway were analysed by immunoprecipitation and immunoblotting. We demonstrated that a high-fat diet led to an increase in the iNOS protein level and S -nitrosation of insulin receptor , (IR,), insulin receptor substrate 1 (IRS1) and Akt. Interestingly, an acute bout of exercise reduced iNOS expression and S -nitrosation of proteins involved in the early steps of insulin action, and improved insulin sensitivity in diet-induced obesity rats. Furthermore, administration of GSNO (NO donor) prevents this improvement in insulin action and the use of an inhibitor of iNOS (l- N6 -(1-iminoethyl)lysine; l -NIL) simulates the effects of exercise on insulin action, insulin signalling and S -nitrosation of IR,, IRS1 and Akt. In summary, a single bout of exercise reverses insulin sensitivity in diet-induced obese rats by improving the insulin signalling pathway, in parallel with a decrease in iNOS expression and in the S -nitrosation of IR/IRS1/Akt. The decrease in iNOS protein expression in the muscle of diet-induced obese rats after an acute bout of exercise was accompanied by an increase in AMP-activated protein kinase (AMPK) activity. These results provide new insights into the mechanism by which exercise restores insulin sensitivity. [source] Temporal Variations in Microvolt T-Wave Alternans Testing after Acute Myocardial InfarctionANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 2 2007F.E.S.C., Mário Martins Oliveira M.D. Background: Microvolt T-wave alternans (TWA) have been accepted as a tool for assessing vulnerability to ventricular tachyarrhythmias. There is lack of data concerning prospective temporal variations in TWA measurements after acute myocardial infarction (AMI). We analysed the temporal patterns of TWA in post-AMI patients. Methods and Results: TWA tests were performed <1 month (TWA_early) and 6 months (TWA_late) after AMI in 51 consecutive patients treated with successful percutaneous coronary intervention (PCI). Twenty seven patients (53%) had anterior wall infarctions and 24 (47%) had inferior/lateral wall infarctions. TWA was measured during a treadmill manual exercise protocol and defined as positive, negative and indeterminate. Group A included patients with TWA negative in both tests and Group B included those with TWA abnormal (positive or indeterminate) at first or second determinations. TWA_early was negative, positive and indeterminate in 38 (74.6%), 8 (15.6%) and 5 (9.8%) patients, respectively, whereas TWA_late was negative, positive and indeterminate in 30 (58.9%), 14 (27.4%) and 7 (13.7%) patients, respectively. TWA_early was classified as normal in 74.6% and abnormal in 25.4% of the cases, and TWA_late was normal in 58.9% and abnormal in 41.1%. TWA tests were concordant in 36 patients (70.6%) and discordant 15 patients (29.4%). At TWA_late, 10 patients (19.6%) changed from TWA negative to TWA abnormal and 4 patients (7.8%) from TWA abnormal to TWA negative. After TWA_early+TWA_late, 45% of the patients had 1 test classified as abnormal. Left ventricular ejection fraction was <50% in 22% of Group A and 52% of Group B (P = 0.037). Conclusions: In the era of primary PCI, temporal changes in TWA measurements may occur frequently during the first 6 months post-AMI. These findings should be considered in risk stratification strategies following AMI. [source] Elevation of anions in exercise-induced acidosis: a study by ion-exchange chromatography/mass spectrometryBIOMEDICAL CHROMATOGRAPHY, Issue 3 2008William McKinnon Abstract Acidosis is a major factor that determines the upper limit of exercise endurance. We have previously shown that anions usually associated with intermediary metabolism are elevated in critically ill patients with metabolic acidosis and contribute significantly to acidosis generation. This study was to determine whether volunteers with normal metabolism would exhibit similar elevations in anions associated with intermediate metabolism when exposed to a short-term physiological stress leading to a brief lactic acidosis. Physiological stress was induced on five healthy male subjects by means of a ramped exercise protocol. Blood was obtained immediately prior to and post-exercise, plasma ultrafiltrate was prepared and analysed immediately both by enzyme assay and liquid chromatography coupled to electrospray,mass spectrometry (LC/ESI-MS). Metabolic acidosis concomitant with a significant increase in blood lactate occurred in each subject, but in addition, anions normally associated with intermediate metabolism were significantly elevated after exercise. The contribution of these anions to generating an acidosis, and thus potentially limiting the extent of exercise, has never been acknowledged. Copyright © 2007 John Wiley & Sons, Ltd. [source] Effect of exercise on upper extremity pain and dysfunction in head and neck cancer survivorsCANCER, Issue 1 2008A randomized controlled trial Abstract BACKGROUND. Shoulder pain and disability are well recognized complications associated with surgery for head and neck cancer. This study was designed to examine the effects of progressive resistance exercise training (PRET) on upper extremity pain and dysfunction in postsurgical head and neck cancer survivors. METHODS. Fifty-two head and neck cancer survivors were assigned randomly to PRET (n = 27) or a standardized therapeutic exercise protocol (TP) (n = 25) for 12 weeks. The primary endpoint was change in patient-rated shoulder pain and disability from baseline to postintervention. Secondary endpoints were upper extremity strength and endurance, range of motion, fatigue, and quality of life. RESULTS. Follow-up assessment for the primary outcome was 92%, and adherence to the supervised PRET and TP programs were 95% and 87%, respectively. On the basis of intention-to-treat analyses, PRET was superior to TP for improving shoulder pain and disability (,9.6; 95% confidence interval [95% CI], ,16.4 to ,4.5; P = .001), upper extremity strength (+10.8 kg; 95% CI, 5.4,16.2 kg; P < .001), and upper extremity endurance (+194 repetitions × kg; 95% CI, 10,378 repetitions × kg; P = .039). Changes in neck dissection impairment, fatigue, and quality of life favored the PRET group but did not reach statistical significance. CONCLUSIONS. The PRET program significantly reduced shoulder pain and disability and improved upper extremity muscular strength and endurance in head and neck cancer survivors who had shoulder dysfunction because of spinal accessory nerve damage. Clinicians should consider the addition of PRET in the rehabilitation of postsurgical head and neck cancer survivors. Cancer 2008. © 2008 American Cancer Society. [source] Comparison of oxidative capacity among leg muscles in humans using gated 31P 2-D chemical shift imagingNMR IN BIOMEDICINE, Issue 10 2009Sean C. Forbes Abstract In many small animals there are distinct differences in fiber-type composition among limb muscles, and these differences typically correspond to marked disparities in the oxidative capacities. However, whether there are similar differences in the oxidative capacity among leg muscles in humans is less clear. The purpose of this study was to compare the rate of phosphocreatine (PCr) recovery, a functional in vivo marker of oxidative capacity, in the lateral and medial gastrocnemius, soleus, and the anterior compartment of the leg (primarily the tibialis anterior) of humans. Subjects performed plantar flexion and dorsiflexion gated exercise protocols consisting of 70 sets of three rapid dynamic contractions (<2.86,s) at 20,s intervals (total: 23.3,min). Starting after the sixth set of contractions, 31P 2-D CSI (8,×,8 matrix, 14,16,cm FOV, 3,cm slice, TR 2.86,s) were acquired via a linear transmit/receive surface coil using a GE 3T Excite System. The CSI data were zero-filled (32,×,32) and a single FID was produced for each time point in the lateral and medial gastrocnemius, soleus, and anterior compartment. The time constant for PCr recovery was calculated from ,,=,-,t/ln[D/(D,+,Q)], where Q is the percentage change in PCr due to contraction during the steady-state portion of the protocol, D the additional drop in PCr from rest, and ,t is the interval between contractions. The , of PCr recovery was longer (p,<,0.05) in the anterior compartment (32,±,3,s) than in the lateral (23,±,2,s) and medial gastrocnemius muscles (24,±,3,s) and the soleus (22,±,3,s) muscles. These findings suggest that the oxidative capacity is lower in the anterior compartment than in the triceps surae muscles and is consistent with the notion that fiber-type phenotypes vary among the leg muscles of humans. Copyright © 2009 John Wiley & Sons, Ltd. [source] Resistance exercise-induced increases in putative anabolic hormones do not enhance muscle protein synthesis or intracellular signalling in young menTHE JOURNAL OF PHYSIOLOGY, Issue 21 2009Daniel W. D. West We aimed to determine whether exercise-induced elevations in systemic concentration of testosterone, growth hormone (GH) and insulin-like growth factor-1 (IGF-1) enhanced post-exercise myofibrillar protein synthesis (MPS) and phosphorylation of signalling proteins important in regulating mRNA translation. Eight young men (20 ± 1.1 years, BMI = 26 ± 3.5 kg m,2) completed two exercise protocols designed to maintain basal hormone concentrations (low hormone, LH) or elicit increases in endogenous hormones (high hormone, HH). In the LH protocol, participants performed a bout of unilateral resistance exercise with the elbow flexors. The HH protocol consisted of the same elbow flexor exercise with the contralateral arm followed immediately by high-volume leg resistance exercise. Participants consumed 25 g of protein after arm exercise to maximize MPS. Muscle biopsies and blood samples were taken as appropriate. There were no changes in serum testosterone, GH or IGF-1 after the LH protocol, whereas there were marked elevations after HH (testosterone, P < 0.001; GH, P < 0.001; IGF-1, P < 0.05). Exercise stimulated a rise in MPS in the biceps brachii (rest = 0.040 ± 0.007, LH = 0.071 ± 0.008, HH = 0.064 ± 0.014% h,1; P < 0.05) with no effect of elevated hormones (P= 0.72). Phosphorylation of the 70 kDa S6 protein kinase (p70S6K) also increased post-exercise (P < 0.05) with no differences between conditions. We conclude that the transient increases in endogenous purportedly anabolic hormones do not enhance fed-state anabolic signalling or MPS following resistance exercise. Local mechanisms are likely to be of predominant importance for the post-exercise increase in MPS. [source] QT Variability during Rest and Exercise in Patients with Implantable Cardioverter Defibrillators and Healthy ControlsANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 1 2009Mark C. Haigney M.D. Background: Increased QT Variability (QTVI) is predictive of life threatening arrhythmias in vulnerable patients. The predictive value of QTVI is based on resting ECGs, and little is known about the effect of acute exercise on QTVI. The relation between QTVI and arrhythmic vulnerability markers such as T-wave alternans (TWA) has also not been studied. This study examined the effects of exercise on QTVI and TWA in patients with arrhythmic vulnerability. Methods: Digitized ECGs were obtained from 47 ICD patients (43 males; age 60.9 ± 10.1) and 23 healthy controls (18 males; age 59.7 ± 9.5) during rest and bicycle exercise. QTVI was assessed using a previously validated algorithm and TWA was measured as both a continuous and a categorical variable based on a priori diagnostic criteria. Results: QTVI increased with exercise in ICD patients (,0.79 ± 0.11 to 0.36 ± 0.08, P < 0.001) and controls (,1.50 ± 0.07 to ,0.19 ± 0.12, P < 0.001), and QTVI levels were consistently higher in ICD patients than controls during rest and exercise (P < 0.001). The magnitude of QTVI increase from baseline levels was not larger among ICD patients versus controls (P > 0.20). Among ICD patients, elevated exercise QTVI was related to lower LV ejection fraction and inducibility of ischemia (P < 0.05). QTVI at rest correlated with exercise TWA (r = 0.54, P = 0.0004). Conclusions: QT variability increases significantly with exercise, and exercise QTVI is related to other well-documented markers of arrhythmic vulnerability, including low ejection fraction, inducible ischemia, and TWA. Resting QTVI may be useful in the risk stratification of individuals incapable of performing standard exercise protocols. [source] | |||||||||||||