Home  About us  Contact
 

Exercise Test (exercise + test)

Distribution by Scientific Domains
Medical Sciences78%
Life Sciences13%
Distribution within Medical Sciences
Cardiovascular Disease24%
Neurology7%
16 Other Subdomains62%

Kinds of Exercise Test

  • cardiopulmonary exercise test
    		•
  • incremental exercise test
    		•
  • treadmill exercise test
    		•

    Selected Abstracts

    The Effect of Antihistamine Cetirizine on Ventricular Repolarization in Congenital Long QT Syndrome

    JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2007
    ANNA-MARI HEKKALA M.D.
    Introduction: Many drugs are known to block cardiac potassium channels, thus prolonging QT interval and predisposing to malignant arrhythmias. Patients with congenital long QT syndrome are particularly vulnerable, but usually electrophysiological effects of drugs have not been assessed in these patients at risk. Methods: Fifteen asymptomatic patients with type 1 (LQT1), 15 patients with type 2 (LQT2) long QT syndrome, and 15 healthy volunteers took a placebo and cetirizine 10 mg. In addition, healthy volunteers took cetirizine 50 mg. The study was single-blinded and randomized. Exercise tests were performed during stable plasma concentrations. The electrocardiogram was recorded with a body surface potential mapping system (BSPM). Data were analyzed with an automated analyze program. QT intervals to the T wave apex and T wave end and their difference (Tp-e) were determined at rest and at specified heart rates during and after exercise. Results: Cetirizine did not lengthen the QT intervals at rest or during exercise and recovery in any group. It shortened Tp-e at rest in LQT1 and LQT2 patients and during exercise test in LQT1 patients, thus slightly decreasing electrocardiographic transmural dispersion of repolarization. Conclusions: Cetirizine does not adversely modify ventricular repolarization in types 1 and 2 long QT syndrome, suggesting that it might be used safely in these long QT syndrome patients. [source]

    Morvan's syndrome: Clinical, laboratory, and in vitro electrophysiological studies

    MUSCLE AND NERVE, Issue 2 2004
    Wolfgang N. Löscher MD
    Abstract Morvan's syndrome is a rare disorder characterized by neuromyotonia, hyperhidrosis, and central nervous system dysfunction. We report a patient with features of this syndrome, but who initially presented with breathing difficulties. Concentric needle electromyography showed an abundance of myokymic and neuromyotonic discharges. Exercise tests and repetitive nerve stimulation showed a decrement,increment response of compound muscle action potentials. Antibodies against voltage-gated potassium channels were not detected on repeated testing, but the presence of oligoclonal bands in the cerebrospinal fluid (CSF) suggested an autoimmune etiology. At follow-up over 3 years, no cancer was found. Electrophysiological in vitro studies of effects of patient serum and CSF on rat nerves provided no evidence of altered voltage-gated sodium or potassium conductances. We conclude that putative humoral factors do not block ion channels acutely but may cause channel dysfunction with chronic exposure. Muscle Nerve 30: 157,163, 2004 [source]

    Pulmonary diffusion and aerobic capacity: is there a relation?

    ACTA PHYSIOLOGICA, Issue 4 2010
    Does obesity matter?
    Abstract Aim:, We sought to determine whether pulmonary diffusing capacity for nitric oxide (DLNO), carbon monoxide (DLCO) and pulmonary capillary blood volume (Vc) at rest predict peak aerobic capacity (O2peak), and if so, to discern which measure predicts better. Methods:, Thirty-five individuals with extreme obesity (body mass index or BMI = 50 ± 8 kg m,2) and 26 fit, non-obese subjects (BMI = 23 ± 2 kg m,2) participated. DLNO and DLCO at rest were first measured. Then, subjects performed a graded exercise test on a cycle ergometer to determine O2peak. Multivariate regression was used to assess relations in the data. Results:, Findings indicate that (i) pulmonary diffusion at rest predicts O2peak in the fit and obese when measured with DLNO, but only in the fit when measured with DLCO; (ii) the observed relation between pulmonary diffusion at rest and O2peak is different in the fit and obese; (iii) DLNO explains O2peak better than DLCO or Vc. The findings imply the following reference equations for DLNO: O2peak (mL kg,1 min,1) = 6.81 + 0.27 × DLNO for fit individuals; O2peak (mL kg,1 min,1) = 6.81 + 0.06 × DLNO, for obese individuals (in both groups, adjusted R2 = 0.92; RMSE = 5.58). Conclusion:, Pulmonary diffusion at rest predicts O2peak, although a relation exists for obese subjects only when DLNO is used, and the magnitude of the relation depends on gender when either DLCO or Vc is used. We recommend DLNO as a measure of pulmonary diffusion, both for its ease of collection as well as its tighter relation with O2peak. [source]

    Impaired oxygen kinetics in beta-thalassaemia major patients

    ACTA PHYSIOLOGICA, Issue 3 2009
    I. Vasileiadis
    Abstract Aim:, Beta-thalassaemia major (TM) affects oxygen flow and utilization and reduces patients' exercise capacity. The aim of this study was to assess phase I and phase II oxygen kinetics during submaximal exercise test in thalassaemics and make possible considerations about the pathophysiology of the energy-producing mechanisms and their expected exercise limitation. Methods:, Twelve TM patients with no clinical evidence of cardiac or respiratory disease and 10 healthy subjects performed incremental, symptom-limited cardiopulmonary exercise testing (CPET) and submaximal, constant workload CPET. Oxygen uptake (Vo2), carbon dioxide output and ventilation were measured breath-by-breath. Results:, Peak Vo2 was reduced in TM patients (22.3 ± 7.4 vs. 28.8 ± 4.8 mL kg,1 min,1, P < 0.05) as was anaerobic threshold (13.1 ± 2.7 vs. 17.4 ± 2.6 mL kg,1 min,1, P = 0.002). There was no difference in oxygen cost of work at peak exercise (11.7 ± 1.9 vs. 12.6 ± 1.9 mL min,1 W,1 for patients and controls respectively, P = ns). Phase I duration was similar in TM patients and controls (24.6 ± 7.3 vs. 23.3 ± 6.6 s respectively, P = ns) whereas phase II time constant in patients was significantly prolonged (42.8 ± 12.0 vs. 32.0 ± 9.8 s, P < 0.05). Conclusion:, TM patients present prolonged phase II on-transient oxygen kinetics during submaximal, constant workload exercise, compared with healthy controls, possibly suggesting a slower rate of high energy phosphate production and utilization and reduced oxidative capacity of myocytes; the latter could also account for their significantly limited exercise tolerance. [source]

    Lifestyle, participation, and health-related quality of life in adolescents and young adults with myelomeningocele

    DEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 11 2009
    LAURIEN M BUFFART PHD
    This study aimed to describe participation and health-related quality of life (HRQoL) in adolescents and young adults with myelomeningocele and to explore their relationships with lifestyle-related factors. Fifty-one individuals with a mean age of 21 years 1 month (SD 4y 6mo) years participated (26 males, 25 females; 82% hydrocephalus, 55% wheelchair-dependent). Participation was assessed using the Life Habits Questionnaire, and HRQoL was assessed using the Medical Outcomes Study 36-item Short-form Health Survey. Physical activity was measured using an accelerometry-based activity monitor, fitness (peak oxygen uptake) was measured during a maximal exercise test, and the sum of four skin-folds was assessed to indicate body fat. Relationships were studied using logistic regression analyses. Of the participants, 63% had difficulties in daily activities and 59% in social roles. Participants perceived lower physical HRQoL than a Dutch reference population. Participants with higher levels of physical activity and fitness had fewer difficulties in participating in daily activities (odds ratio [OR]=8.8, p=0.02 and OR=29.7, p=0.02 respectively) and a higher physical HRQoL (OR=4.8, p=0.02 and OR=30.2, p=0.006 respectively), but not mental HRQoL. Body fat was not related to participation or HRQoL. In conclusion, a large proportion of individuals with myelomeningocele had difficulties in participation and perceived low physical HRQoL. Higher levels of physical activity and fitness were related to fewer difficulties in participation and higher physical HRQoL. [source]

    Does aerobic fitness influence microvascular function in healthy adults at risk of developing Type 2 diabetes?

    DIABETIC MEDICINE, Issue 4 2005
    A. R. Middlebrooke
    Abstract Aim To investigate whether aerobic fitness is associated with skin microvascular function in healthy adults with an increased risk of developing Type 2 diabetes. Methods Twenty-seven healthy normal glucose-tolerant humans with either a previous diagnosis of gestational diabetes or having two parents with Type 2 diabetes and 27 healthy adults who had no history of diabetes were recruited. Maximal oxygen uptake was assessed using an incremental exercise test to exhaustion. Skin microvascular function was assessed using laser Doppler techniques as the maximum skin hyperaemic response to a thermal stimulus (maximum hyperaemia) and the forearm skin blood flow response to the iontophoretic application of acetylcholine (ACh) and sodium nitroprusside. Results Maximal oxygen uptake was not significantly different in the ,at-risk' group compared with healthy controls. Maximum hyperaemia was reduced in those ,at risk' (1.29 ± 0.30 vs. 1.46 ± 0.33 V, P = 0.047); however, the peak response to acetylcholine or sodium nitroprusside did not differ in the two groups. A significant positive correlation was demonstrated between maximal oxygen uptake and maximum hyperaemia (r = 0.52, P = 0.006 l/min and r = 0.60, P = 0.001 ml/kg/min) and peak ACh response (r = 0.40, P = 0.04 l/min and r = 0.47, P = 0.013 ml/kg/min) in the ,at-risk' group when expressed in absolute (l/min) or body mass-related (ml/kg/min) terms. No significant correlations were found in the control group. Conclusions In this ,at-risk' group with skin microvascular dysfunction maximal oxygen uptake was not reduced compared with healthy controls. However, in the ,at-risk' group alone, individuals with higher levels of aerobic fitness also had better microvascular and endothelial responsiveness. [source]

    Thyroid hormone responses to endurance exercise

    EQUINE VETERINARY JOURNAL, Issue S36 2006
    E. A. GRAVES
    Summary Reasons for performing study: Limited information exists about changes in circulating thyroid hormone concentrations during prolonged endurance exercise in horses. Objective: To examine the effects of prolonged exercise on serum iodothyronine concentrations in horses performing endurance exercise of varying distances. Methods: Serum concentrations of iodothyronines were measured in horses before and after completion of 40, 56, 80 and 160 km endurance rides (Study 1); daily during a 5 day, 424 km endurance ride (Study 2); and before and for 72 h after completion of a treadmill exercise test simulating a 60 km endurance ride (Study 3). Results: In Study 1, 40 and 56 km of endurance exercise had little effect on serum iodothyronine concentrations with the exception of a 10% decrease (P<0.05) in free thyroxine (FT4) concentration after the 56 km ride. In contrast, total thyroxine (T4), total triiodothyronine (T3), FT4 and free triiodothyronine (FT3) concentrations all decreased (P<0.05) after successful completion of 80 and 160 km rides, with decreases ranging from 13,31% and 47,54% for distances of 80 and 160 km, respectively. Further, pre-ride T4 concentration was lower (P<0.05) and FT3 concentration was higher (P<0.05) in horses competing 160 km as compared to horses competing over shorter distances. In Study 2, serum concentrations of T4, T3 and reverse triiodothyronine (rT3) progressively decreased (P<0.05) over the course of the multi-day ride. In Study 3, the greatest decrease (P<0.05) in all iodothyronines was observed at 12 h of recovery, ranging from 25% for FT4 to 53% for FT3, but all thyroid hormone concentrations had returned to the pre-exercise values by 24 h of recovery. Conclusion: Endurance exercise results in transient decreases in serum iodothyronine concentrations. Potential relevance: These data are important to consider when thyroid gland function is assessed by measurement of serum iodothyronine concentrations in endurance horses. [source]

    Body composition in young Standardbreds in training: relationships to body condition score, physiological and locomotor variables during exercise

    EQUINE VETERINARY JOURNAL, Issue S36 2006
    C. LELEU
    Summary Reasons for performing study: Body composition is an essential factor in athletic performance of human sprinters and long distance runners. However, in horses, many questions remain concerning relationships between body composition and performance in the different equine activities. Objectives: To determine relationships between body composition, body score, physiological and locomotor variables in a population of young Standardbreds in training. Methods: Twenty-four 2-year-old Standardbreds were studied, body condition on a scale 0,5 and bodyweight recorded, and height at withers measured. Percentage of fat (%F), fat mass (FM) and fat free mass (FFM) were estimated echographically. During a standardised exercise test on the track, velocity, heart rate, respiratory frequency and blood lactate concentrations were measured. V4 and V200 (velocity for a blood lactate concentration of 4 mmol/1 and velocity of 200 beats/min) calculated. Basic gait variables were measured at 3 different speeds with an accelerometric device. Results: Body composition variables: %F and FM were significantly related to body condition score and physiological variables. Body score was highly correlated to %F (r=0.64) and FM (r = 0.71). V4 was negatively correlated to %V (r=-0.59) and FM (r = -0.60), P<0.05. V200 was also negatively related to %F and FM, (r=-0.39 and r = -0.37, respectively, P<0.1). No relationships were found between body composition and gait characteristics. Conclusions: Body composition was closely related to indirect measurements of aerobic capacity, which is a major factor of athletic performance in middle distance running horses. Potential relevance: As in human athletes, trainers should take special note to evaluate optimal bodyweight and body composition of race horses to optimise performance. [source]

    Is improved high speed performance following frusemide administration due to diuresis-induced weight loss or reduced severity of exercise-induced pulmonary haemorrhage?

    EQUINE VETERINARY JOURNAL, Issue S36 2006
    X. A. ZAWADZKAS
    Summary Reasons for performing study: Prerace administration of frusemide to horses has been linked with a significant improvement in racing performance, but the basis for this improvement is unclear. Objective: To test whether improved performance with prerace administration of frusemide is due to the drug's diuresis-induced weight loss rather than its apparent alleviation of exercise-induced pulmonary haemorrhage (EIPH). Methods: Eight thoroughbred horses underwent 3 trials in a random order, 2 or 3 weeks apart: control (C), frusemide/unburdened (FU), and frusemide/burdened (FB). None of the horses were known to have exhibited post-exercise epistaxis or endoscopic evidence of EIPH. Endoscope-guided bronchoalveolar lavages (BALs) were performed before and after each horse completed a standardised exercise test (SET) on an inclined treadmill to assess semi-quantitatively the volume of EIPH. For C, horses received an i.v. saline placebo injection (5 ml) and were unburdened while performing the SET. With FU, horses received frusemide (0.5 mg/kg) and were also unburdened. For FB, horses received frusemide and were burdened with weight equal to that lost during the 4 h post frusemide injection period. Erythrocyte number in BAL fluid, mass specific VO2max, time and distance for the entire SET as well as at maximum speed were recorded. A one-way repeated measures analysis of variance was conducted on all results. Results: Mass specific VO2max was significantly higher for the FU than for FB or C. Mass specific VO2max for FB and C were not different. More RBCs were found in BAL samples after C runs than after both FU and FB trial runs. Horses with the frusemide treatment (either burdened or unburdened) produced less EIPH than in the C trial, but their mass specific VO2max values were higher on the FU trial alone. For FU, horses ran longer at 115% VO2max than under C or FB conditions. Conclusion and potential relevance: Improvement of performance in the furosemide trials was due more to the weight-loss related effects of the drug than its apparent alleviation of EIPH. Further research is warranted with the same or similar project design, but with a larger sample size and with horses known to have more severe EIPH. [source]

    Oral vitamin E supplementation on oxidative stress, vitamin and antioxidant status in intensely exercised horses

    EQUINE VETERINARY JOURNAL, Issue S36 2006
    C. A. WILLIAMS
    Summary Reasons for performing study: Vitamin E is the most commonly supplemented antioxidant in horses; however, previous research is not conclusive as to the recommended level for exercising horses. Objective: To evaluate the effects of 3 levels of vitamin E supplementation on oxidative stress and vitamin/antioxidant status in intensely exercised horses to determine the optimal level of vitamin E supplementation. Methods: Twelve unfit Standardbreds were divided into 3 groups, supplemented orally with 0 (CON), 5000 (MOD), or 10,000 (HI) iu/day of DL-,-tocopheryl acetate. The 3 times 3 Latin square design consisted of three 4 week supplementation periods with 4 week wash out periods between. After each period, horses underwent a treadmill interval exercise test. Blood samples were collected and heart rate (HR) measured before, during and after exercise. Data were analysed using ANOVA with repeated measures in SAS. Results: The CON group had lower HR throughout the test compared to the MOD and HI groups (P<0.05). There was an increase in plasma retinol (RET), ,-carotene (BC), red blood cell total glutathione and glutathione peroxidase with exercise (P<0.05), but all groups returned to baseline after 24 h. Plasma ,-tocopherol (TOC) increased from baseline with exercise (P<0.0001) in all groups; treatment differences were observed at 24 h (P<0.05). The HI and CON groups had lower BC compared to the MOD group (P = 0.05). Conclusions: Horses supplemented with vitamin E, at nearly 10-times the 1989 NRC recommended level, did not experience lower oxidative stress compared to control horses. Additionally, lower plasma BC levels observed in the HI group, which may indicate that vitamin E has an inhibitory effect on BC metabolism. Potential relevance: Supplementation above control levels is not more beneficial to oxidative stress and antioxidant status in intensely exercising horses; indeed, levels 10 times in excess may be detrimental to BC and should be avoided. [source]

    Application of a constant blood withdrawal method in equine exercise physiology studies

    EQUINE VETERINARY JOURNAL, Issue 6 2001
    P. BARAGLI
    Summary The aim of the present study was to test a constant blood withdrawal method (CBWM) to collect blood samples from horses during treadmill exercise. CBWM was performed in 4 Standardbreds and 5 Haflinger horses. A peristaltic pump was used to control blood aspiration from an i.v. catheter via an extension line. Blood was collected using an automatic fractions collector, with a constant delay time between the drawing of blood and sample collection. Blood withdrawal using CBWM was made during a treadmill standardised exercise test (SET). A blood flow of 12 ml/min was used and samples collected every 60 s during the entire period of exercise. The volume of blood collected in each sample tube was 12.1 ± 0.2 ml, with a delay time of mean ± s.d. 25.3 ± 0.8 s. Plasma lactate kinetics based on measurement of lactate in each fraction showed an exponential increase during the first 13 min of exercise (10.5 min of SET and 2.5 min recovery). The peak plasma lactate concentration was observed between 2.5 and 5.5 min after the end of SET. CBWM permits the kinetics of lactate and other blood-borne variables to be studied over time. This method could be a valuable aid for use in studying equine exercise physiology. [source]

    Electromyographic and kinematic indicators of fatigue in horses: a pilot study

    EQUINE VETERINARY JOURNAL, Issue S33 2001
    G. R. COLBORNE
    Summary Muscle fatigue can be quantified using Fourier analysis of the recorded EMG signal. Median frequency is the frequency at which the Fourier profile is bisected, and this measure typically shifts to smaller values during fatigue. This technique was combined with kinematic analysis to describe the time course of fatigue in horses galloping on an inclined treadmill. It was hypothesised that EMG median frequency would decrease in tandem with changes in kinematic variables through the exercise test. Three fit Thoroughbred horses had retroreflective markers placed on their hooves and withers. Surface electrodes were attached to the skin over the forelimb deltoid muscle. After warm-up at walk and trot, each horse galloped at 110% VO2max on a treadmill inclined to 7.5% until fatigue onset. Kinematic data were recorded at 200 Hz for 5 s at 30s intervals, and raw EMG data were recorded at 1024 Hz for 3 s at 15 s intervals. Fatigue onset was the point in time when the horse could not keep up with the treadmill speed with minimal encouragement. One horse performed the entire exercise test on the same lead, while the other 2 horses changed leads periodically, interrupting the changes in both the EMG and kinematic measurements. Overall, through the course of the trials, mean stride length increased by 0.34 m and stride duration increased by 0.03 s. Vertical excursion of the trunk marker increased by 0.03 m. For the horse that did not change lead, median frequency of the EMG signal decreased by 36%. In the other 2 horses, lead changes were interspersed between smaller decreases in median frequency, whereupon median frequency recovered to starting levels immediately following a lead change. The median frequency decreased by 12-20% between lead changes. Kinematic changes are more global indictors of fatigue, while the EMG indicators are dependent upon lead changes. [source]

    Evaluation of the one-minute exercise test to detect peripheral arterial disease

    EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 5 2008
    E. K. Hoogeveen
    ABSTRACT Background,, Asymptomatic peripheral arterial disease (PAD) is common amongst the elderly and is a risk factor for cardiovascular morbidity and mortality. PAD can be assessed by non-invasive tests such as the ankle/brachial pressure index (ABPI) at rest and Doppler flow velocity (DFV) scanning, but these tests may underestimate the prevalence of PAD. The aim of this study was to estimate the added value, for the detection of PAD, of the one-minute exercise test, defined as positive if the drop of the ankle systolic pressure was more than 30 mmHg. We also investigated whether the combination of the ABPI at rest and the one-minute exercise test could replace DFV scanning. Materials and methods,, We studied this in a random sample (n = 631) of a 50- to 75-year-old population. Results,, Of these subjects 11% (66/631) had an abnormal ABPI (< 0·9) and 16% (102/631) had an abnormal DFV curve. Of this sample 72% of the subjects performed a one-minute exercise test. Of all subjects 6% (27/451) had an abnormal ABPI (< 0·9) and 12% (54/451) had an abnormal DFV curve. The one-minute exercise test revealed seven cases of PAD (beyond the 67 already identified) which were not detected by an abnormal ABPI at rest and/or DFV scanning. As a result the prevalence of PAD increased by 2%. All patients with an aortoiliac or femoropopliteal obstruction had an ABPI at rest < 0·9. The sensitivity of the combination of the ABPI at rest and the one-minute exercise test to detect abnormal DFV curves was low for crural obstructions. Conclusion,, The one-minute exercise test slightly improves the detection of peripheral arterial disease in the general population. [source]

    Phosphoglycerate kinase deficiency in two brothers with McArdle-like clinical symptoms

    EUROPEAN JOURNAL OF NEUROLOGY, Issue 1 2000
    J. Aasly
    Phosphoglycerate kinase (PGK) catalyses the transfer of the acylphosphate group of 1,3-diphosphoglycerate to ADP with formation of 3-phosphoglycerate and ATP in the terminal stage of the glycolytic pathway. Two young brothers are presented who both experienced muscle pain, cramps and stiffness shortly after beginning heavy exercise. After these episodes they noticed that the urine was dark brown, indicating rhabdomyolysis and myoglobinuria. The neurological examinations were without remarks. There was no lactate increase in the ischaemic forearm exercise test. Both had very low PGK levels in muscle, erythrocytes, leukocytes and fibroblasts. This is the first family with more than one affected case of PGK deficiency and exercise-induced stiffness, myalgia and rhabdomyolysis. The clinical manifestations may resemble myophosphorylase deficiency (McArdle's disease: glycogenosis Type V) and muscle phosphofructokinase deficiency (Tarui's disease: glycogenosis Type VII). PGK deficiency is inherited as an X-linked trait and may show other features such as mental retardation and/or haemolytic anaemia. [source]

    Revisiting Autonomic Dysfunction in End-Stage Renal Disease Patients

    HEMODIALYSIS INTERNATIONAL, Issue 3 2003
    Jocemir R. Lugon
    Background:,Autonomic dysfunction is frequent in end-stage renal disease (ESRD) patients, but both the relative involvement of the parasympathetic and sympathetic branches and the role of antihypertensive drugs in this setting are still controversial. The present study addressed these issues employing a battery of standard noninvasive cardiovascular autonomic tests. Methods:,Sympathetic (S) function was evaluated by responses of both systolic blood pressure (BP) to passive tilting and diastolic BP to handgrip; parasympathetic (P) function, through the respiratory sinus arrhythmia test and the heart rate response to the 4-s unloaded exercise test. Additional tests influenced by both branches of the autonomic system (P + S) were accomplished by the assessment of heart rate response to the Valsalva maneuver, handgrip, and tilting. Results:,Studied subjects belonged to one of the three groups: ESRD patients not requiring BP medications (n = 11; 8 men, 3 women); ESRD patients receiving antihypertensive therapy (n = 36; 21 men, 15 women); and apparently healthy controls (n = 15; 10 men, 5 women). When the variables grouped according to the branch of the autonomic nervous system predominantly probed were analyzed, only the frequency of impaired sympathetic autonomic responses was higher in ESRD patients not receiving BP drugs compared to controls (55 vs. 23%, P = 0.040). In contrast, when ESRD patients receiving BP drugs were compared to controls, the differences became significant in S, P, and P + S tests (46 vs. 23%, P = 0.045; 22 vs. 3%, P = 0.020; and 34 vs. 13%, P = 0.010, respectively). With the criterion of more than one positive finding in any of the variables examined for diagnosing autonomic dysfunction, the prevalence of autonomic dysfunction was 20% in controls, 64% in ESRD patients not receiving BP drugs (P = 0.005 vs. controls), and 67% in ESRD patients receiving BP drugs (P = 0.043 vs. controls). Conclusions:,ESRD continues to be associated with a high prevalence of autonomic dysfunction. ESRD patients receiving BP drugs were found to have detectable impairment in the entire autonomic system in contrast to those not receiving BP drugs in whom inadequate responses were restricted to the sympathetic branch. [source]

    Effects of glucose polymer with and without potassium and different diets on glycogen repletion after a treadmill exercise test in endurance horses

    JOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 11-12 2005
    T. M. Hess
    Glycogen repletion involves absorption of glucose and its uptake into the muscle cells through GLUT-4 transporters. In the muscle and adipose tissue GLUT,4 transporters facilitates the glucose transport in the presence of insulin and K+. Potassium supply has been shown to stimulate insulin secretion. This study tested the effects of a glucose polymer added with electrolytes containing potassium (GP+K) compared to a glucose polymer with electrolytes without potassium (GP-K) on glycogen repletion. Also it compared the effect of different diet adaptations on glycogen repletion. Six horses were fed a diet rich in sugar and starch (SS), and six horses a diet rich in fat and fibre (FF) for 6 months before the test. In a crossover designed study, 12 trained Arabian or Arabian cross horses were submitted to a glycogen depleting exercise test on the treadmill. After exercise stopped six horses were supplied with GP-K and six other horses supplied with GP+K, at a dose of 5 g/kg BW, and a rate of 1 g/kg BW/hour through naso-gastric gavage. Muscle biopsies were taken before, just after they stopped exercise, and 16 h after they had been supplied with glycogen replacing formulas, and analysed for muscle glycogen. Blood was taken before, after 3 h of exercise, after the stepwise exercise test, at 0, 1 and 4 h after exercise stopped and analysed for plasma glucose, insulin and [K+]. Muscle glycogen decreased from 516.41 ± 12.92 glucosyl units/kg dry weight muscle to 408.74 ± 12.92 glucosyl units/kg dry weight muscle (79%). Sixteen hours after the repletion protocol horses recovered their muscle glycogen to 458.53 ± 12.91 glucosyl units/kg dry weight muscle (89%). Plasma glucose had a glucose polymer by sampling effect (p = 0.013) and a feed by sampling effect (p = 0.022). Plasma glucose was higher in SS fed horses at 1 and 4 h after exercise. Plasma glucose was lower in GP+K supplied horses 4 h after exercise. Plasma insulin had a trend (p = 0.070) for a glucose polymer effect. No differences were found in muscle glycogen between the two GP treatments. Although the present results demonstrate that intensive nasogastric supplementation with glucose polymer can result in glycogen repletion approaching that following i.v. administration, the addition of potassium conferred no advantage. [source]

    Metabolic responses to oral tryptophan supplementation before exercise in horses

    JOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 3-6 2005
    I. Vervuert
    Summary This study was conducted to evaluate the effects of oral tryptophan (Trp) supplementation on exercise capacity and metabolic responses in horses. Three horses had to perform an exercise test: a 15-min warm-up followed by a 60-min walk (1.7 m/s, W1), a 10-min trot (3.1 m/s, T1), a second 60-min walk (1.7 m/s, W2), a second 10-min trot (3.1 m/s, T2) and a final 30-min walk (1.7 m/s, W3) until the horses were unwilling to continue. The horses exercised on a treadmill at a 6% incline and with a constant draught load of 40 kg (0.44 kN). Two hours before exercise horses were given 50 g Trp (9.8,10.7 g Trp/100 kg BW) by nasogastric tube. A control exercise test was conducted without Trp. During the control test, one horse was able to finish the final 30-min walk (W3), whereas two horses finished W3 after Trp administration. Higher plasma Trp levels after Trp administration did not change significantly during exercise (Trp: start exercise, 524 ± 41 ,mol/l; end exercise 547 ± 20 ,mol/l; control: start exercise, 70 ± 10 ,mol/l; end exercise, 58 ± 21 ,mol/l). After Trp supplementation, blood lactate concentrations were significantly lower after the first and second trotting periods. Free fatty acids in plasma increased during exercise without any treatment-related differences. Although experimental plasma Trp levels were seven times higher than the control levels, Trp supplementation had no effect on exercise performance and metabolic responses to draught load exercise. [source]

    Enhanced Predictive Power of Quantitative TWA during Routine Exercise Testing in the Finnish Cardiovascular Study

    JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2009
    MIKKO MINKKINEN B.M.S.
    Introduction: We examined whether quantification of T-wave alternans (TWA) enhances this parameter's capacity to evaluate the risk for total and cardiovascular mortality and sudden cardiac death (SCD). Methods and Results: The Finnish Cardiovascular Study (FINCAVAS) enrolled consecutive patients (n = 2,119; 1,342 men and 777 women) with a clinically indicated exercise test with bicycle ergometer. TWA (time domain-modified moving average method) was analyzed from precordial leads, and the results were grouped in increments of 10 ,V. Hazard ratios (HR) for total and cardiovascular mortality and SCD were estimated for preexercise, routine exercise, and postexercise stages. Cox regression analysis was performed. During follow-up of 47.1 ± 12.9 months (mean ± standard deviation [SD]), 126 patients died: 62 were cardiovascular deaths, and 33 of these deaths were sudden. During preexercise, TWA , 20 ,V predicted the risk for total and cardiovascular mortality (maximum HR >4.4 at 60 ,V, P < 0.02 for both). During exercise, HRs of total and cardiovascular mortality were significant when TWA measured ,50 ,V, with 90 ,V TWA yielding maximum HRs for total and cardiovascular death of 3.1 (P = 0.03) and 6.4 (P = 0.002), respectively. During postexercise, TWA ,60 ,V indicated risk for total and cardiovascular mortality, with maximum HR of 3.4 at 70 ,V (P = 0.01) for cardiovascular mortality. SCD was strongly predicted by TWA levels ,60 ,V during exercise, with maximum HR of 4.6 at 60 ,V (P = 0.002), but was not predicted during pre- or postexercise. Conclusion: Quantification of TWA enhances its capacity for determination of the risk for total and cardiovascular mortality and SCD in low-risk populations. Its prognostic power is superior during exercise compared to preexercise or postexercise. [source]

    The Effect of Antihistamine Cetirizine on Ventricular Repolarization in Congenital Long QT Syndrome

    JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2007
    ANNA-MARI HEKKALA M.D.
    Introduction: Many drugs are known to block cardiac potassium channels, thus prolonging QT interval and predisposing to malignant arrhythmias. Patients with congenital long QT syndrome are particularly vulnerable, but usually electrophysiological effects of drugs have not been assessed in these patients at risk. Methods: Fifteen asymptomatic patients with type 1 (LQT1), 15 patients with type 2 (LQT2) long QT syndrome, and 15 healthy volunteers took a placebo and cetirizine 10 mg. In addition, healthy volunteers took cetirizine 50 mg. The study was single-blinded and randomized. Exercise tests were performed during stable plasma concentrations. The electrocardiogram was recorded with a body surface potential mapping system (BSPM). Data were analyzed with an automated analyze program. QT intervals to the T wave apex and T wave end and their difference (Tp-e) were determined at rest and at specified heart rates during and after exercise. Results: Cetirizine did not lengthen the QT intervals at rest or during exercise and recovery in any group. It shortened Tp-e at rest in LQT1 and LQT2 patients and during exercise test in LQT1 patients, thus slightly decreasing electrocardiographic transmural dispersion of repolarization. Conclusions: Cetirizine does not adversely modify ventricular repolarization in types 1 and 2 long QT syndrome, suggesting that it might be used safely in these long QT syndrome patients. [source]

    Heterogeneous Regional Endocardial Repolarization is Associated with Increased Risk for Ischemia-Dependent Ventricular Fibrillation after Myocardial Infarction

    JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 8 2003
    Michael H. Swann M.SC.
    Introduction: The aim of this study was to investigate whether the characteristics of endocardial ventricular repolarization are associated with differential risk for sudden death. Prolonged surface QT interval is associated with increased arrhythmic risk after myocardial infarction (MI), but the underlying mechanism of QT prolongation and its relation to lethal arrhythmias are unclear. Methods and Results: Ventricular fibrillation (VF) risk was assessed in 12 dogs 1 month after anterior MI during an exercise test coupled with brief circumflex coronary occlusion. Susceptible dogs (n = 5) developed VF during the brief ischemic episode, whereas resistant dogs did not (n = 7). Surface QT interval was measured at rest. Endocardial electroanatomic catheter maps of left ventricular repolarization were obtained in four unique regions identified by echocardiography and compared between groups. Compared to resistant dogs, susceptible dogs were characterized by prolonged surface QT intervals (240 ± 10 msec vs 222 ± 7 msec, P = 0.04). In addition, they had lower baroreflex sensitivity (9.7 ± 1.5 msec/mmHg vs 28 ± 9.8 msec/mmHg, P < 0.01) and a tachycardic response to acute ischemia suggesting higher propensity for stronger sympathetic reflexes. Surface QT interval prolongation in susceptible dogs was due to a marked heterogeneity of endocardial left ventricular repolarization (239 ± 42 msec, basal anterior wall vs 197 ± 35, lateral wall; P < 0.001). Resistant animals had no regional differences in endocardial repolarization. Conclusion: Sympathetic activation following MI not only produces adverse structural remodeling but also contributes to adverse electrophysiologic remodeling resulting in heterogeneous ventricular repolarization and in a myocardial substrate conducive to lethal reentrant arrhythmias. (J Cardiovasc Electrophysiol, Vol. 14, pp. 873-879, August 2003) [source]

    Exercise Does Not Increase QTcmax and QTcd in Diabetic Patients with Autonomic Neuropathy

    PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 12 2007
    MEHMET YAZICI M.D.
    Background:The purpose of this study was to examine the effects of exercise on maximum QTc interval (QTcmax) and QTc dispersion (QTcd) in diabetic patients without clinically evident heart disease. Methods: Seventy-six diabetic patients who had no coronary artery disease or hypertension (group I; mean age 48 ± 9 years old) and 40 healthy volunteers (group II; mean age 46 ± 13 years old) were enrolled in the study. Cases with clinically evident heart disease were excluded from the study. Resting 12-lead electrocardiogram (ECG) and maximal treadmill exercise test (according to Bruce protocol) were performed in all cases. The QTcmax interval was determined at rest (RQTcmax) and during peak exercise (PQTcmax). Also, the QTcd was measured at rest (RQTcd) and during peak exercise (PQTcd). Autonomic neuropathy was assessed by measuring the heart rate variability (HRV). Results: There was no significant difference between clinical characteristics of two groups. In group I, HRV parameters were significantly lower than group II. RQTcd, PQTcd, RQTcmax, and PQTcmax were significantly longer in group I (56 ± 16 vs 34 ± 11; P< 0.001, 62 ± 22 vs 40 ± 15; P < 0.001, respectively). In diabetic patients, there was no significant difference between RQTcmax and PQTcmax (428 ± 19 vs 420 ± 31; P > 0.05), and no significant difference was present between RQTcd and PQTcd (56 ± 16 vs 62 ± 22; P > 0.05, respectively). Conclusion: Exercise does not affect QTcd in patients with diabetes mellitus and without clinically evident heart disease. [source]

    Impairment of Coronary Microvascular Function in Patients with Neurally Mediated Syncope

    PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2p1 2003
    JAW-WEN CHEN
    CHEN, J.-W., et al.: Impairment of Coronary Microvascular Function in Patients with Neurally Mediated Syncope.Recent evidence suggests that myocardial ischemia may occur in patients with neurally mediated syncope and normal coronary angiograms. This study was conducted to evaluate if coronary microvascular function is impaired in such patients. Coronary hemodynamic studies and head-up tilt table tests (HUTs) were performed on 30 consecutive patients with normal coronary angiograms and recurrent syncope. Another ten subjects with atypical chest pain and no evidence of myocardial ischemia or syncope served as a control. Great cardiac vein flow (GCVF) and coronary sinus flow (CSF) were measured by the thermodilution method at baseline and after dipyridamole infusion (0.56 mg/kg IV for 4 minutes). Coronary flow reserve (CFR), derived from CSF and GCVF, was significantly lower in the 15 patients with positive HUT than in the other 15 patients with negative HUT (1.75 ± 0.48vs2.64 ± 0.8, P < 0.01and2.29 ± 0.45vs3.07 ± 0.63, P < 0.01, respectively). Ischemic-like ECG was noted during treadmill exercise test in 40% of the former and in 7% of the latter group(P = 0.01). There was no significant difference in CFR between patients with negative HUT and control subjects. Coronary microvascular function was impaired in syncopal patients with positive HUT and relatively preserved in those with negative HUT, suggesting the possible linkage between coronary microvascular dysfunction and the development of neurally mediated syncope. (PACE 2003; 26[Pt. I]:605,612) [source]

    Health-related fitness and trainability in children with cystic fibrosis

    PEDIATRIC PULMONOLOGY, Issue 10 2008
    W. Gruber MSc
    Abstract The objective of this study was to examine the effects of a supervised exercise training program performed during an in patient rehabilitation course on various attributes of health-related fitness, e.g., flexibility, balance and coordination. 286 patients with CF, age range 6,18 years (11.8,±,3.4 years), mean forced expiratory volume in 1 sec (FEV1 82.7,±,22.3% predicted) were included. Patients performed the modified Munich fitness test (mMFT) to assess flexibility, balance, strength and coordination. To assess aerobic capacity a 6-min walk-test (6MWT) was performed. In addition, some of the patients performed an incremental exercise test on a bicycle ergometer using the Godfrey protocol before and after the exercise training program. The supervised training program consisted of 4,6 weeks of different sports activities 5 times per week. After training, pulmonary function showed a significant (P,<,0.05) increase. All test items of the mMFT improved significantly (P,<,0.05). Compared to healthy children test scores achieved from children with CF in the mMFT were lower but within a normal range. Our children with CF had a lower walk distance in 6MWT (P,<,0.05) compared to healthy. Our findings clearly demonstrated benefits of a systematic exercise training program on components of physical fitness in patients with CF, with improvements of test-tasks to predicted normal in some cases. The results from our study suggested that an exercise training program in CF should be focused on several aspects of physical fitness including all components of physical fitness, e.g. aerobic endurance, flexibility, balance and motor skills. Pediatr Pulmonol. 2008; 43:953,964. © 2008 Wiley-Liss, Inc. [source]

    Effects of single-dose fluticasone on exercise-induced asthma in asthmatic children: A pilot study,

    PEDIATRIC PULMONOLOGY, Issue 2 2001
    B.J. Thio MD
    Abstract A single high dose of inhaled corticosteroid (ICS) can increase airway caliber in children with asthma attacks and laryngitis subglottica. Presumably the effect is due to the vasoconstrictive and antiedematous properties of topical steroids. Enlarged vessels have been suggested to play a role in the pathophysiology of exercise-induced bronchial obstruction (EIB). To investigate this, we evaluated the effect of a single high dose of fluticasone propionate (FP) on EIB in asthmatic children. Nine children aged 8,16 years with mild to moderate asthma were included. All children had a history of EIB, which was confirmed by an exercise test. None was taking ICS maintenance therapy. The children inhaled either a single dose of 1 mg FP or placebo on 2 separate days within 7,14 days. After inhalation, airway caliber (FEV1) was assessed for 4 hr before exercise. Then an exercise challenge was performed on a treadmill to assess EIB (% fall FEV1). A significant increase in FEV1 was observed 1 hr after inhalation of FP compared to placebo. Response to exercise was expressed as maximal % fall in FEV1 from baseline (% fall) and as area under the curve (AUC) of the 30-min time/response curve. The % fall FEV1 after exercise and the AUC were significantly reduced when FP was inhaled compared to placebo inhalation (% fall 9.7% vs. 19.2%, respectively, P,=,0.038 and AUC 92.0%,min vs. 205.7%,min, respectively, P,=,0.03). There was considerable individual variability in reduction of EIB, with 5 out of 9 children having a clinically significant response. We conclude that a single high dose of inhaled FP has an acute protective effect on the bronchial response to exercise in a substantial proportion of asthmatic children. Pediatr Pulmonol. 2001; 32:115,121. © 2001 Wiley-Liss, Inc. [source]

    Physical fitness indices and anthropometrics profiles in schoolchildren with sickle cell trait/disease

    AMERICAN JOURNAL OF HEMATOLOGY, Issue 2 2007
    Hisham 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]

    Influence of successive bouts of fatiguing exercise on perceptual and physiological markers during an incremental exercise test

    PSYCHOPHYSIOLOGY, Issue 1 2009
    Jeremy B.J. Coquart
    Abstract The purpose of this study was to examine the effects of a succession of fatiguing stages, on ratings of perceived exertion (RPE) and estimated time limits (ETL) during an incremental exercise test. Twenty-seven cyclists performed a continuous incremental test and a discontinuous test with randomized workloads. A linear mixed model was used to compare the RPE, ETL, respiratory gas, heart rate, and blood data obtained during the two exercise tests. RPE and ETL were not significantly different between the tests. Ventilation, breathing frequency, heart rate, and blood lactate concentration were significantly higher during the last incremental test workloads. In conclusion, although the incremental exercise test generated higher cardiorespiratory and muscular workloads than observed during the randomized exercise test, most likely due to a greater fatiguing process, these higher workloads did not influence the perceptual response. [source]

    The effect of antecedent fatiguing activity on the relationship between perceived exertion and physiological activity during a constant load exercise task

    PSYCHOPHYSIOLOGY, Issue 5 2007
    Roger Eston
    Abstract This study assessed the relationship between the rate of change of the rating of perceived exertion (RPE), physiological activity, and time to volitional exhaustion. After completing a graded exercise test, 10 participants cycled at a constant load equating to 75% of peak oxygen uptake (V, O2peak) to exhaustion. Participants performed two further constant load exercise tests at 75%V, O2peak in a fresh state condition within the next 7 days. The RPE was regressed against time and percentage of the time (%time) to volitional exhaustion in both conditions. Despite a lower respiratory exchange ratio (RER) and higher heart rate at the start of the exercise bout in the fatigued condition, there were no differences in RPE at the onset or completion of exercise. As expected, the rate of increase in RPE was greater in the fatigued condition, but there were no differences when expressed against %time. Results suggest that RPE is set at the start of exercise using a scalar internal timing mechanism, which regulates RPE by altering the gain of the relationship with physiological parameters such as heart rate and RER when these are altered by previous fatiguing exercise. [source]

    Influence of nitric oxide synthase inhibition on pulmonary O2 uptake kinetics during supra-maximal exercise in humans

    THE JOURNAL OF PHYSIOLOGY, Issue 2 2004
    Daryl P. Wilkerson
    We have recently reported that inhibition of nitric oxide synthase (NOS) with NG -nitro- l -arginine methyl ester (l -NAME) accelerates the ,phase II' pulmonary O2 uptake kinetics following the onset of moderate and heavy intensity submaximal exercise in humans. These data suggest that the influence of nitric oxide (NO) on mitochondrial function is an important factor in the inertia to aerobic respiration that is evident in the transition from a lower to a higher metabolic rate. The purpose of the present study was to investigate the influence of l -NAME on pulmonary kinetics following the onset of supra-maximal exercise, where it has been suggested that O2 availability represents an additional limitation to kinetics. Seven healthy young men volunteered to participate in this study. Following an incremental cycle ergometer test for the determination of , the subjects returned on two occasions to perform a ,step' exercise test from a baseline of unloaded cycling to a work rate calculated to require 105%, preceded either by systemic infusion of l -NAME (4 mg kg,1 in 50 ml saline) or 50 ml saline as a control (Con). Pulmonary gas exchange was measured on a breath-by-breath basis throughout the exercise tests. The duration of ,phase I' was greater with l -NAME (Con: 14.0 ± 2.1 versusl -NAME: 16.0 ± 1.6 s; P= 0.03), suggestive of a slower cardiovascular adaptation following the onset of exercise. However, the phase II time constant was reduced by 44% with l -NAME (Con: 36.3 ± 17.3 versusl -NAME: 20.4 ± 8.3 s; P= 0.01). The accumulation of blood lactate during exercise was also reduced with l -NAME (Con: 4.0 ± 1.1 versusl -NAME: 2.7 ± 2.1 mm; P= 0.04). These data indicate that skeletal muscle NO production represents an important limitation to the acceleration of oxidative metabolism following the onset of supra-maximal exercise in humans. [source]

    Fiberoptic videolaryngoscopy during bicycle ergometry: A diagnostic tool for exercise-induced vocal cord dysfunction

    THE LARYNGOSCOPE, Issue 9 2009
    Hanna Tervonen MD
    Abstract Objectives/Hypothesis: Exercise-induced vocal cord dysfunction is difficult to diagnose because the paradoxical vocal cord adduction should be observed during exercise. Our goal was to develop and validate a new diagnostic method for exercise-induced vocal cord dysfunction by combining continuous fiberoptic laryngoscopy with a bicycle ergometry test. Methods: Thirty consecutive patients referred to a laryngologist because of suspicion of exercise-induced vocal cord dysfunction and 15 healthy controls underwent the exercise test until dyspnea or exhaustion rated as 18,19/20 on the Borg scale. Laryngeal findings, electrocardiography, blood pressure, heart rate, and respiratory rate were monitored, and forced expiratory flow in the first second was measured before and after the exercise. The medical history was assessed by use of a structured questionnaire. Results: Among the 30 patients, 27 (90%) performed the test successfully, as did all controls. Diagnostic signs of inspiratory stridor, supraglottic collapse, and vocal cord adduction appeared in five (19%) patients but in none of the controls. Of the 30 patients referred, the laryngologist considered 25 to be suspect. Of them, 9 (36%) showed signs diagnostic or highly suspect for exercise-induced vocal cord dysfunction. Of the 15 patients whose dyspnea could be induced during the test, nine (60%) were suspected of having exercise-induced vocal cord dysfunction. Conclusions: Fiberoptic videolaryngoscopy during bicycle ergometry was a well-tolerated and relatively easily established diagnostic tool that could induce dyspnea in more than one half the patients examined. If the symptom of dyspnea appeared, the most frequent diagnosis was exercise- induced vocal cord dysfunction. Laryngoscope, 2009 [source]

    Cardiac Arrhythmias Triggered by Sudden and Dynamic Efforts

    ANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 2 2010
    Emanuel C. Furtado M.D.
    Background: Some arrhythmias are triggered only during exercise. The aim of this study is to describe the frequency and type of arrhythmia induced by a standardized protocol of sudden and dynamic exercise, which tends to reflect routine situations of efforts (e.g., climbing stairs), and compare with those found on maximal cardiopulmonary exercise test (CPET). Methods: A total of 2329 subjects (1594 men) aged 9,91 years (mean 52 years, SD ± 16) were submitted to a standardized protocol of sudden and dynamic exercise (4-second exercise test [4sET]) prior to a CPET. A continuous digital electrocardiogram (ECG) was recorded during 4sET and CPET, and later reviewed and interpreted by the same physician (who supervised all the procedures). Results: A total of 1125 subjects (43%) had cardiac arrhythmias during one or both procedures. About 57% of the arrhythmias were supraventricular, but 47 subjects (2% of all subjects) presented more complex arrhythmias including 43 cases of nonsustained supraventricular tachycardia and four nonsustained ventricular tachycardia. While arrhythmias were more often exposed by the CPET (P < 0.01), in 221 cases (10% of the total sample) of arrhythmias they were only induced by 4sET; these included four cases of nonsustained supraventricular tachycardia. Conclusion: 4sET-induced arrhythmias tend to be simple and were always short-lasting. In some cases, ECG recording during 4sET showed arrhythmias that would not be induced by a progressive maximal exercise test. Different situations of exercise, sudden and short versus maximal and progressive, tend to generate different arrhythmic responses and possibly complementary clinical implications. Ann Noninvasive Electrocardiol 2010;15(2):151,156 [source]