Standardized Exercise Test Research Articles

The Effect of Creatine Supplementation on Muscle Function in Childhood Myositis: A Randomized, Double-blind, Placebo-controlled Feasibility Study.

To evaluate the feasibility of studying creatine in juvenile dermatomyositis (JDM). Secondary objectives were to determine the effect of creatine on muscle function and metabolism, aerobic capacity, fatigue, physical activity, and quality of life (QOL), as well as its safety. We conducted a 6-month, double-blind, randomized, multiple-baseline design; patients were assigned to creatine or placebo. Feasibility was assessed using attended study visits, completed study procedures, and adherence. Muscle function, aerobic capacity, and muscle strength were assessed with standardized exercise tests. Muscle metabolism was assessed using a 31-Phosphorus Magnetic Resonance Spectroscopy protocol. Fatigue, physical activity, and QOL were assessed by questionnaires. Statistical significance was estimated using a randomization (permutation) test. Changes in outcome measures taken at baseline and end-of-study were calculated using paired t-tests. Median (range) adherence to the study drug was 88.5% (20.5-95.5%) and the proportion of subjects with 80% adherence or higher was 76.9%. There were no missed study visits. There were no statistically significant changes in muscle function, strength, aerobic capacity, disease activity, fatigue, physical activity, or QOL while subjects were receiving creatine compared to placebo. There were statistically significant adaptations in muscle metabolism (e.g., decrease in change in muscle pH following exercise, and decrease in phosphate/phosphocreatine ratio) at the end-of-study compared to baseline. There were no significant adverse effects. Creatine supplementation in children with JDM is feasible to study, and is safe and well-tolerated; it may lead to improvements in muscle metabolism.

Smart textiles biotechnology for electrocardiogram monitoring in horses during exercise on treadmill: Validation tests.

There are several bioengineering solutions aimed at improving human health and welfare. Smart electrodes based on textile substrates have met the growing demand for comfort, reliability, and robustness when acquiring physiological signals. Given the importance of good quality electrocardiograms (ECG) in equine sports medicine, this study focuses on the validation of smart textile electrodes to acquire ECG signals in horses during treadmill exercise. The performance of the smart textile electrodes is compared with standard silver/silver chloride (Ag/AgCl) electrodes in terms of signal quality. Five healthy Standardbred mares were fitted with two identical electronic systems for the simultaneous recording of ECGs during a standardised exercise test (SET) on a treadmill. One system was equipped with smart textile electrodes, whereas the second was equipped with standard Ag/AgCl electrodes. The Ag/AgCl electrodes were positioned on shaved skin with self-adhesive pads, and without (SET1) or with glue (SET2). The textile electrodes were positioned without shaving the skin. The Kurtosis (k) value for each ECG trace recorded was calculated as an index of ECG signal quality. For the textile electrodes, k values were higher, and closer to ideal compared to Ag/AgCl electrodes. The median values of the Signal Quality Indexes (kSQI) were higher for textile compared to Ag/AgCl electrodes. These differences were significant in SET 2 (P<.001), but not in SET 1 (P=.08). This study was limited to treadmill exercise that did not include a rider or harness. During treadmill exercise, textile electrodes are a practical solution for collecting good quality ECG traces.

The Immune Response To Cardiorespiratory Exercise Testing In Heart Failure Patients With Reduced Ejection Fraction

PURPOSE: Long-term exercise training reduces systemic inflammation in heart failure patients. However, due to the impaired immune system in these patients, an acute exercise challenge may trigger pro-inflammatory responses. We compared the acute response to a standardized cardiopulmonary exercise test (CPET) in patients with heart failure with reduced ejection fraction (HFrEF) to age and gender matched controls. METHODS: Patients with HFrEF (n=13; left ventricular ejection fraction [LVEF] < 40%) and controls (n=14, LVEF > 50%) participated in a CPET. Blood samples were taken before, immediately after and 2 hours after CPET. Flow cytometry was used to assess quantitative and morphological alterations in leukocyte subpopulations as well as the formation of leukocyte-platelet aggregates. Only significant findings are reported (p < 0.05) and are given as median and inter-quartile range (IQR). RESULTS: HFrEF (mean LVEF: 36%) and controls (mean LVEF: 57%) were 59 (range: 41 to 80) and 57 (range: 50 to 65) years old, respectively. CPET increased the leukocyte (control: 1.37-fold [IQR: 1.16 to 1.49]; HFrEF: 1.24-fold [IQR: 1.20 to 1.32]), natural killer (NK) cell (controls: 2.11-fold [IQR: 1.30 to 3.13]; HFrEF: 1.67-fold [IQR: 1.56 to 1.71]) and NK-T cell (control: 1.69-fold [IQR: 1.52 to 3.60]; HFrEF: 1.62-fold [IQR: 1.60 to 2.53]) concentration in the HFrEF and control group. CD4+ cells (control: 1.15-fold [IQR: 0.84 to 1.54]; HFrEF: 1.45-fold [IQR: 1.10 to 1.98]) and CD8+ T-cells (control: 1.33-fold [IQR: 1.01 to 1.68]; HFrEF: 1.70-fold [IQR: 1.25 to 2.15]) only increased in HFrEF patients. Aggregation of thrombocytes with monocytes (control: 0.86-fold [IQR: 0.78 to 1.49]; HFrEF: 1.59-fold [IQR: 1.05 to 7.30-fold]), T-lymphocytes (control: 1.27-fold [IQR: 1.05 to 1.68]; HFrEF: 1.49-fold [IQR: 1.03 to 2.64]) and neutrophils (control: 1.08-fold [IQR: 0.87 to 1.25]; HFrEF: 2.13-fold [IQR: 1.62 to 2.19]) increased 2 hour post CPET in patients with HFrEF, but not in controls. CONCLUSIONS: CPET differentially induced specific immune responses in patients with HFrEF compared to age and gender matched controls. The prolonged immune response in these patients suggests differences in immune resolving mechanisms which deserve further research.

Improved Exercise Tolerance, Oxygen Delivery, and Oxygen Utilization After Transcatheter Aortic Valve Implantation for Severe Aortic Stenosis

BackgroundTranscatheter aortic valve implantation (TAVI) represents an effective therapeutic procedure, particularly in patients with severe aortic stenosis. We hypothesized that the decreased afterload induced by TAVI would improve exercise capacity by enhancing oxygen uptake in working muscles. MethodsA standardized exercise test was performed in patients with severe aortic stenosis the day before TAVI and within 5 days thereafter. The main study endpoint was the workload achieved during a 5-minute standardized exercise test. Using electrical cardiometry and near-infrared spectroscopy, we explored and compared the changes in cardiac index (CI), as well as muscular and cerebral tissue oximetry, during the 2 exercise tests. ResultsThirty patients completed the study protocol. Compared with the pre-TAVI period, patients achieved a higher median workload after TAVI (316 Joules [interquartile range {IQR}: 169–494] vs 190 Joules [IQR: 131–301], P = 0.002). Baseline CI increased from 2.5 l/min per m2 (IQR: 2.1–2.9) to 2.9 l/min per m2 (IQR: 2.5–3.2; P = 0.009), whereas CI at the end of the exercise test increased from 4.5 l/min per m2 (IQR: 3.4–5.3) to 4.7 l/min per m2 (3.4–6.4; P = 0.019). At the end of the exercise test, cerebral tissue oximetry increased from 70% (IQR: 65–72) to 74% (IQR: 66–78), and muscle tissue oximetry increased from 62% (IQR: 58–65) to 71% (65–74; P = 0.046 and P < 0.001, respectively). ConclusionsEarly improvement of exercise capacity after TAVI is associated with increased CI and better oxygen utilization in the brain and skeletal muscles.

Comparison of physiological demands in Warmblood show jumping horses over a standardized 1.10\u2009m jumping course versus a standardized exercise test on a track

BackgroundA greater understanding of exercise physiology and biochemistry is required for the sport horse disciplines, including show jumping. Conditioning of horses for show jumping is empirical because they are primarily trained on flat ground, however the equivalent workload between jumping and flat work is currently unknown. The objectives of the study were therefore to compare the physiological demands of Warmblood show jumpers over a standardized 1.10 m course vs a 600 m standardized incremental exercise test on flat ground, and to report reference field test values for competitive show jumping horses. In this prospective field study, 21 healthy, actively competing Warmblood show jumping horses were assessed to determine physiological variables after a standardized jumping course at 6.4 m/s (average speed) and track standardized incremental exercise test at 5 m/s, 8 m/s and 11 m/s. Heart rate, velocity, blood lactate, blood pH, pCO2, bicarbonate, PCV and TP concentrations were recorded. V200, V170 and VLa4 were calculated. Parametric statistics were performed on analysis of all 21 horses’ variables.ResultsContrary to exercise at 5 m/s and 11 m/s, cantering at 8 m/s did not induce any significant difference in blood lactate, mean heart rate or mean venous blood pH compared to after completion of the jumping course.ConclusionsJumping a 1.10 m course demands a statistically similar workload to cantering around a flat track at 8 m/s. This study will help to test fitness and design conditioning programs for Warmblood show jumping horses.

Association of Cardiorespiratory Fitness and Hemodynamic Responses to Submaximal Exercise Testing With the Incidence of Chronic Kidney Disease: The Framingham Heart Study

ObjectiveTo relate cardiorespiratory fitness (CRF) and hemodynamic responses to exercise to the incidence of chronic kidney disease (CKD). MethodsWe evaluated 2715 Framingham Offspring Study participants followed up (mean, 24.8 years) after their second examination (1979-1983) until the end of their ninth examination (2011-2014). Participants (mean age, 43 years; 1397 women [51.5%]) without prevalent CKD or cardiovascular disease at baseline were included. We examined the associations of CRF and hemodynamic response to exercise with incident CKD using multivariable Cox proportional hazards regression with discrete intervals. ResultsCompared with low CRF (first tertile), participants with moderate (second tertile) or high (third tertile) CRF had a lower risk of CKD (hazard ratios [95% CIs]: 0.74 [0.61-0.91] and 0.73 [0.59-0.91], respectively). Participants with chronotropic incompetence (hazard ratio, 1.38 [95% CI, 1.06 to 1.79]), higher exercise systolic blood pressure (hazard ratio per SD, 1.20 [95% CI, 1.07 to 1.34]), and impaired heart rate recovery (hazard ratio, 1.51 [95% CI, 1.08 to 2.10]) had a higher risk of CKD compared with those with chronotropic competence, lower exercise systolic blood pressure, and normal heart rate recovery, respectively. These associations remained robust when the exercise variables were mutually adjusted for. The third tertile of a standardized exercise test score comprising the statistically significant variables was associated with a higher risk of CKD compared with the first tertile (hazard ratio, 1.85; 95% CI, 1.45 to 2.36). ConclusionHigher CRF and favorable hemodynamic responses to submaximal exercise in young adulthood may be markers of lower risk of CKD in later life.

Exercise Field Testing in Children: A New Approach for Age-Appropriate Evaluation of Cardiopulmonary Function

Based on the wide range of problems to effectively perform cardiopulmonary testing in young children, this study strives to develop a new cardiopulmonary exercise test for children using a mobile testing device worn in a backpack in order to test children during their natural movement habits, namely, running outdoors. A standard cardiopulmonary exercise ramp test on a cycle ergometer was performed by a group of twenty 7–10-year-old children. The results were compared with a self-paced incremental running test performed using a mobile cardiopulmonary exercise measuring device in an outdoor park. The children were able to reach significantly higher values for most of the cardiopulmonary exercise variables during the outdoor test and higher. Whereas a plateau in {dot{text{V}}text{O}}_{{2}} was reached by 25% of the children during the outdoor test, only 75% were able to reach a reasonable VT2, let alone {dot{text{V}}text{O}}_{{{text{2peak}}}}, during the bicycle test. The heart rate at VT1, the O2-pulse, and the OUES were comparable between both tests. OUES was also positively correlated with {dot{text{V}}text{O}}_{{{text{2peak}}}} in both tests. Testing children outdoors using a mobile cardiopulmonary exercise unit represents an alternative to standard exercise testing, but without the added problems of exercise equipment like treadmills or bicycles. It allows for individualized exercise testing with the aim of standardized testing durations instead of standardized testing protocols. The running speeds determined during the outdoor tests may then be used to develop age-adapted testing protocols for treadmill testing.

Form of Vitamin E Supplementation Affects Oxidative and Inflammatory Response in Exercising Horses

Vitamin E is an essential antioxidant that may benefit athletes by reducing oxidative stress and influencing cytokine expression. Supplements can be derived from natural or manufactured synthetic sources. This study aimed to determine (1) if supplemental vitamin E is beneficial to exercising horses and (2) if there is a benefit of natural versus synthetic vitamin E. After 2 weeks on the control diet (vitamin E–deficient grain and hay), 18 horses were divided into three groups and fed the control diet plus (1) 1000 IU/d synthetic α-tocopherol (SYN-L), (2) 4000 IU/d synthetic α-tocopherol (SYN-H), or (3) 4000 IU/d RRR-α-tocopherol (natural source [NAT]). On day 7, horses began a 6-week training protocol, with standard exercise tests (SETs) performed before and after the 6-week protocol. Venous blood samples were collected on days 0, 7, 29, and 49. Horses fed NAT had higher α-tocopherol (P < .05) at post-SET1 through post-SET2. Plasma thiobarbituric acid–reactive substance levels were lower in NAT versus SYN-L horses after SET2 (P = .02). Serum aspartate aminotransferase was lower after exercise in NAT horses versus SYN-L and SYN-H (P = .02), and less reduction in stride duration was seen after exercise in NAT as compared with SYN-L and SYN-H (P = .02). Gene expression of tumor necrosis factor α was lower in NAT compared with SYN-H (P = .01) but not SYN-L. In conclusion, feeding higher levels of natural vitamin E source resulted in higher serum α-tocopherol levels as well as some improvement in oxidative and inflammatory response and improved functional outcomes in response to an exercise test.

Transporting and Exercising Unconditioned Horses: Effects on Microflora Populations

The objective of this study was to determine if transportation and exercise stress in horses affect the microflora populations in the equine hindgut. Four horses were subjected to three transport periods (0, 3, and 6 hours) with a 7-d rest period between each transport. Horses were fed 0.91 kg/day of Purina Impact All Stages 12% and had ad libitum access to Cynodon dactylon (Coastal Bermudagrass) hay. Fecal samples were collected before (0 hours) and after (48 hours) transport. In addition, three horses underwent a different standardized exercise test with a 7-d rest period between each exercise. Standardized exercise test intensity was determined by heart rate to validate if the horse was in aerobic or anaerobic work. The protocol for fecal sample collection after exercise was the same as for transport. Prokaryotic community profiling was conducted by 16S metagenomic analysis. After DNA evaluation, differences were found in the microbiome at transport 0 hours and grouped transport 3 hours time 48 and transport 6 hours time 48 (PERMANOVA P = .037) where Bacteroidetes increased 48 hours after transport and Firmicutes decreased 48 hours after transport. Exercise microbial communities showed no difference in either alpha or beta diversity when compared with controls (0 hours). In the present study, difference in microflora may have resulted from stress duration of transport rather than stress duration of exercise.

Abstract P6-10-16: High circulating levels of adrenomedullin are associated with metabolic syndrome and low cardiorespiratory fitness in BRCA1 and BRCA2 mutation carriers

Abstract BACKGROUND: Risk factors for cardiovascular disease (CVD) and breast cancer overlap substantially. Identification of the underlying mechanisms associated with this co-occurrence is of great public health importance. Adrenomedullin (AM) is an almost ubiquitously expressed peptide with vasodilator and natriuretic properties. Previous studies have observed a link between high AM levels and worse prognosis in patients with myocardial infarction and heart failure, indicating a crucial role in the pathophysiology of CVD. Moreover, AM is expressed in 80% of sporadic breast cancers, and the degree of expression is associated with tumour growth, local tumour progression and bone metastases. High plasma AM levels are linked to arterial hypertension, diabetes, obesity and smoking. Preliminary evidence suggests that AM influences the osteoclast differentiation mediated by Receptor Activator of NF-κB Ligand (RANKL), an important signalling pathway in BRCA1-associated breast tumorigenesis. OBJECTIVE: Besides an elevated risk of breast cancer, recent studies revealed that BRCA mutation carriers are potentially at higher cardiovascular risk. The value of AM in BRCA mutation carriers is unknown. The aim of this study was to examine circulating plasma AM levels in BRCA mutation carriers and assess their association with modifiable risk factors. METHODS: AM concentrations were measured in 290 BRCA1/2 mutation carriers without overt CVD, participating in the randomized controlled LIBRE study (NCT numbers: NCT02087592, NCT02516540), by an immunoassay (sphingotest® bio-ADM®). Subjects were classified into high versus low AM levels based on the median plasma AM level in the entire cohort (13.9 pg/mL). Univariate logistic regression models were used to estimate the odds ratio (OR) of having high circulating AM levels by metabolic syndrome (MetS), cardiorespiratory fitness (CRF), body mass index (BMI), circulating insulin, smoking, current age, BRCA mutation status (BRCA1 or BRCA2) and previous diagnosis of breast cancer. MetS was defined in accordance with the criteria of the Third Adult Treatment Panel (ATP III). CRF was measured by peak oxygen uptake (VO2peak) assessed on a cycle ergometer via standardized cardiopulmonary exercise testing. RESULTS: Of all women (median age: 43 years), 57.9% had a previous diagnosis of breast cancer. The median time between diagnosis and study entry was 3 years (range: 0-32 years). Women fulfilling the criteria of metabolic syndrome had over 17 times higher odds of having increased AM levels compared to those who did not meet the criteria (OR = 17.49, p &amp;lt; 0.001). Moreover, high AM levels were associated with lower VO2peak (OR = 0.91, p &amp;lt; 0.001), higher BMI (OR = 1.24, p &amp;lt; 0.001) and higher circulating insulin levels (OR = 1.1, p &amp;lt; 0.001). AM levels were higher in women who have ever smoked (OR = 1.73, p = 0.022), and AM levels increased with the number of pack-years smoked (OR = 1.03, p = 0.06). AM levels were not associated with age (p = 0.143), BRCA mutation status (p = 0.51) or previous diagnosis of breast cancer (p = 0.48). After adjustment for confounding variables, we observed that MetS (OR = 10.78, p = 0.002) and VO2peak (OR = 0.92, p = 0.001) were independent determinants of circulating AM. CONCLUSIONS: This is the first study in BRCA mutation carriers that has linked circulating AM levels to MetS and CRF. The long-term clinical implications of these findings are yet to be determined. Conflict of interest: The study is funded by the German Cancer Aid (Deutsche Krebshilfe) within the Priority Program “Primary Prevention of Cancer” (Grant no. 110013). JS and OH are employed by Sphingotec GmbH, a company having patent rights in and commercializing the bio-ADM assay. SG and MK received grants from Sphingotec GmbH. JL, MYD, MB and MH have nothing to disclose. Citation Format: Jacqueline Lammert, Sabine Grill, Maryam Yahiaoui-Doktor, Maryam Basrai, Joachim Struck, Oliver Hartmann, Martin Halle, Marion Kiechle. High circulating levels of adrenomedullin are associated with metabolic syndrome and low cardiorespiratory fitness in BRCA1 and BRCA2 mutation carriers [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-10-16.

Lipidomic profiles, lipid trajectories and clinical biomarkers in female elite endurance athletes

We assessed whether blood lipid metabolites and their changes associate with various cardiometabolic, endocrine, bone- and energy-related comorbidities of Relative Energy Deficiency in Sport (RED-S) in female elite endurance athletes. Thirty-eight Scandinavian female elite athletes underwent a day-long exercise test. Five blood samples were obtained during the day - at fasting state and before and after two standardized exercise tests. Clinical biomarkers were assessed at fasting state, while untargeted lipidomics was undertaken using all blood samples. Linear and logistic regression was used to assess associations between lipidomic features and clinical biomarkers. Overrepresentations of findings with P < 0.05 from these association tests were assessed using Fisher’s exact tests. Self-organizing maps and a trajectory clustering algorithm were utilized to identify informative clusters in the population. Twenty associations PFDR < 0.05 were detected between lipidomic features and clinical biomarkers. Notably, cortisol demonstrated an overrepresentation of associations with P < 0.05 compared to other traits (PFisher = 1.9×10−14). Mean lipid trajectories were created for 201 named features for the cohort and subsequently by stratifying participants by their energy availability and menstrual dysfunction status. This exploratory analysis of lipid trajectories indicates that participants with menstrual dysfunction might have decreased adaptive response to exercise interventions.

Exercise, Chronotropic and Inotropic Capacity in Athletes with Different Training Programmes

Abstract Amateur sport has significant influence on peoples’ physical activity and affects the prevalence of non-communicable diseases. The population of competing amateur athletes has not been sufficiently studied, and there is a huge gap between functional results of untrained individuals and professional athletes. The aim of the study was to evaluate the exercise capacity and chrono-tropic, inotropic capacity in amateur athletes with different training programmes, as assessed by cardiopulmonary exercise testing. In a longitudinal prospective study, 600 amateur athletes who performed high dynamic load sports, according to the Mitchell Classification of Sports, were assessed. The individuals underwent standard maximum cardiopulmonary exercise testing on the ISO certified Master screen CPX system. The exercise capacity was dependent on the training programme organisation, regularity and duration, but it was not dependent on age. During maximum work-rate, the functional parameters of the cardiorespiratory system and inotropic capacity were significantly dependent on duration of the training programme. Chronotropic and inotropic capacity, as well as cardiorespiratory adaptation were significantly higher for competing amateur athletes of both genders than for untrained individuals. The study showed that amateur athletes with a training programme 300 minutes per week had higher exercise capacity, which was based on the individually suitable training programme, and higher aerobic and anaerobic capacity. Regular pre-competition medical assessment of amateur athletes can be used to objectively evaluate their health condition, adaptation, cardiac risk and make changes in the athletes’ training programme.

The Validity of the YMCA 3-Minute Step Test for Estimating Maximal Oxygen Uptake in Healthy Korean and Vietnamese Adults.

BackgroundCardiorespiratory fitness (CRF) is a fundamental component of physical fitness. While maximal oxygen uptake (VO2max) is the gold standard for quantifying CRF, standard maximal exercise tests using direct measurements VO2max are dependent on the availability of laboratory equipment, and thereby expensive and time consuming. Recently, an equation was formulated to indirectly estimate VO2max using the YMCA 3-minute step test.MethodsThe study included 15 Korean (KR) and 15 Vietnamese (VN) healthy adults aged 19-35 years. All subjects completed a YMCA 3-minute step test (YMCA 3MST) and a maximal exercise treadmill test to predict VO2max and VO2max measures, respectively.ResultsThere was a significant relationship between VO2max predicted from the YMCA 3MST and actual VO2max measurements from the treadmill test (r = 0.80, p < 0.0001; KR group: r = 0.81, p < 0.0001; VN group: r = 0.93, p < 0.0001). Bland-Altman analysis revealed statistical agreement between tests, although there was a systematic overestimation of 3.36 mL/kg/min for the KR group.ConclusionThe equation for predicting VO2max from the YMCA 3MST was validated among the study subjects. However, future research should explore the validity and reliability of the YMCA 3MST equation for estimating VO2max in other populations.

Hormonal Response to Incremental and Continuous Exercise in Cyclists with Left Ventricle Hypertrophy.

The aim of this study was to assess the effects of incremental and continuous exercise on the concentration of insulin-like growth factor-1 (IGF-1), growth hormone (GH), testosterone (T), and cortisol (C), as well as to investigate whether increased cardiac dimensions in cyclists were related to changes in these hormones and cardiac biomarkers. The study included 30 elite cyclists divided into two groups, i.e., athletes with left ventricle hypertrophy (a LVH group), and a control group (CG) without LVH. The study protocol included performance of a standard incremental exercise (IncEx) test to measure athletes’ maximum power (Pmax), maximum oxygen uptake (VO2max), and lactate threshold (LAT). The IncEx test results were then used to determine the intensity of the continuous exercise (ConEx) test which was performed after the 1-week washout period. Cyclists with LVH and without LVH did not differ in resting hormone concentrations and cardiac biomarkers levels. There was a significant effect of exercise on serum IGF-1 levels (p < 0.05) in the LVH group and a combined effect of the type of exercise and LVH on IGF-1 (p < 0.05). Cyclists with LVH demonstrated higher post exercise T levels recorded in response to exercise compared to the CG (p < 0.01). Significantly higher serum T levels were observed in response to ConEx compared to IncEx in the LVH group and the CG (p < 0.05 and p < 0.05, respectively). In the LVH group, a significant positive correlation between the post-exercise T/C ratio and left ventricular mass index was observed (r = 0.98, p < 0.01). There were no effects of heart hypertrophy on cardiac standard biomarkers. Incremental and continuous exercise caused a marked increase in steroid hormone concentrations and moderate strengthening of insulin growth factors effects. Regular incremental exercise seems to induce beneficial cardiac adaptations via significant increases in the concentration of anabolic factors compared to the same training mode yet with constant exercise intensity.

Influência da altitude e condicionamento físico sobre valores sanguíneos de glicose e lactato em cavalos no exercício de enduro

Os efeitos da altitude sobre parâmetros fisiológicos são amplamente estudados no homem, porém em equinos esses estudos são escassos e pouco conclusivos. O objetivo desse trabalho foi verificar se há influência da altitude em equinos praticantes de enduro em diferentes graus de condicionamento físico nos valores sanguíneos de glicose e lactato, antes e após o exercício de enduro. Foram utilizados 40 equinos praticantes de enduro em diferentes estágios de treinamento. Esses animais foram submetidos a testes físicos em diferentes altitudes, onde foram coletadas amostras de sangue para análise de glicose e lactato antes e após o exercício de enduro. Os animais em início de treinamento sofreram influência da alta altitude com valores maiores de lactato e glicose, enquanto que os animais melhor condicionados fisicamente sofreram pouca influência nesses dois parâmetros independente da altitude. Conclui-se que os animais com melhor condicionamento físico são pouco influenciados pelos efeitos da baixa pressão de oxigênio nos parâmetros avaliados.

Global Positioning System–Determined and Stopwatch-Determined Running Speeds of Horses Differ

Global positioning systems (GPS) have become very popular tools to determine the running speed of horses. However, information on the accuracy of these measurements is scarce. The objective of this study was to examine the accuracy of speed determinations using GPS. For this purpose, the running speeds determined using the GPS of the Polar M400 Equine heart rate meter (G-speed) and a stopwatch (W-speed; manual division of the measured time over the distance run) were compared. The hypothesis was that the speeds determined by both methods would be the same. Eleven horses ran a standardized exercise test (SET) with 130 m laps, and 8 horses ran a SET with 250 m laps in two different sandy riding arenas (one was indoor). The length of the laps was determined with a distance measuring wheel and marked with red traffic cones for the riders to maintain an accurate course. The SETs consisted of five intervals at increasing speeds each. The duration of the intervals was between 3 and 6 minutes. Horses ran a defined number of laps in each interval to reach the prescribed durations. Data were analyzed using a paired Student’s t-test; P < .05 denoted significance. W-speeds differed from G-speeds for all intervals in both riding arenas (P between .01 and .001). G-speed was lower for each interval. With increasing speed, the difference between the two methods augmented. The hypothesis was rejected, therefore questioning the accuracy of the Polar M400 in determining speed under the conditions of this study.

Effect of pimobendan on physical fitness, lactate and echocardiographic parameters in dogs with preclinical mitral valve disease without cardiomegaly.

Pimobendan has gained enormous importance in the treatment of mitral valve disease in dogs. The current consensus statement of the American College of Veterinary Internal Medicine (ACVIM) recommends a treatment for dogs with symptomatic disease and dogs with asymptomatic disease with radiographic and echocardiographic signs of cardiomegaly. To investigate whether these dogs also benefit from a therapy with pimobendan, 21 dogs with mitral valve disease ACVIM B1 underwent a standardized submaximal exercise test on a treadmill. In this double-blinded and randomized study, the animals were divided into two groups, one receiving pimobendan and the other a placebo. At the first visit and at every follow-up appointment (at days 90 and 180), heart rate during the complete exercise test and lactate before and after running were measured. In addition to this, a questionnaire was completed by the dogs’ owners and all dogs were given an echocardiographic examination to detect any changes and to observe if the disease had progressed. Due to the diagnosis of leishmaniosis, one dog in the pimobendan group was retrospectively removed from the study so that 20 dogs were included for statistical analysis. No differences were observed at any time between the pimobendan-group and the placebo-group regarding heart rate. At day 180, the increase in lactate after exercise was significantly lower than in the placebo-group. The increase in the pimobendan-group at day 180 was lower than at day 90. Most of the dog owners from the pimobendan-group declared that their dogs were more active at day 90 (6/10) and at day 180 (8/10), while most dog owners from the placebo-group observed no changes regarding activity at day 90 (8/10) and day 180 (6/10). It can be concluded that the results of this study indicate that some dogs with mitral valve disease ACVIM B1 might benefit from a therapy with pimobendan.

P4409Cardiorespiratory fitness is inversely associated with the inflammatory status in the general population

Abstract Background/Introduction Low-grade systemic chronic inflammation is a major risk factor for cardiometabolic diseases. Higher physical activity has athero- and cardioprotective effects, potentially through its anti-inflammatory properties. However, the relation between resting inflammatory status and cardiorespiratory fitness (CRF) in population-based settings remains to be elucidated. While previous research has shown inverse associations between CRF and high-sensitive C-reactive protein (hs-CRP) levels, relations with other inflammatory markers are not yet well examined. Purpose We assessed the relation between markers of CRF (i.e. maximal oxygen uptake [VO2peak], oxygen uptake at the anaerobic threshold [VO2@AT], oxygen pulse [O2HRmax] and maximal workload [max. Watt]) and hs-CRP as well as total white blood cell (WBC), monocyte, neutrophil, lymphocyte, eosinophil and basophil counts. Methods Data of the population-based cohort Study of Health in Pomerania (SHIP) was used (n=1,481; 51% male; age range 20–81 years). CRF was assessed using standardized cardio-pulmonary exercise testing (CPET) according to a modified Jones protocol. The Dimension Vista 500 analytical system was used to measure hs-CRP concentrations. Fluorescence-activated cell sorting was used to assess total as well as subpopulation WBC count. We excluded subjects with missing data, anti-rheumatic/steroid/anti-inflammatory medication as well as chronic inflammatory and hepatic diseases, gastritis, hepatitis infection, severe renal disease, chronic lung disease, asthma, chronic bronchitis, previous myocardial infarction, left ventricular ejection fraction &lt;40% and previous cancer. Linear regression models, adjusted for age, sex, current smoking and lean-mass, were used to assess the relation between CPET and inflammatory parameters. Results A 14 ml/min (95%-confidence interval [CI] −23 to −6, p=0.004) lower VO2peak was associated with a one mg/L higher hs-CRP. A lower VO2peak was also related with a one Gpt/L greater WBC (β: −42. 95% CI: −55 to −27 ml/min, p&lt;0.001) as well as neutrophil (β: −57, 95% CI: −77 to −36 ml/min, p&lt;0.001), lymphocyte (β: −63, 95% CI: −107 to 19 ml/min, p=0.005) and monocyte count (β: −204, 95% CI: −360 to −47 ml/min, p=0.011). No significant associations were found for eosinophil and basophil count. Similar results were found for VO2@AT, O2HRmax and max. Watt. Conclusion Results suggest an inverse association between CRF and resting inflammatory status. Our non-significant findings with regards to eosinophils and basophils may be expected since these cell types are generally involved in type 2 immune responses related to allergic skin and airway inflammation as well as immunity against parasites. Overall, our results imply that potential biological mechanisms underlying the athero- and cardioprotective effects of high CRF may be related to lower chronic inflammation in fitter individuals.

DOES PHYSIOLOGIC CARDIAC REMODELING IN ENDURANCE ATHLETES ALTER REPOLARIZATION OR QT DYNAMICS?

Increases in QT and QTc duration, and their alterations with changes in heart rate, are associated with dysrhythmias and increased sudden death rates in population studies. Long standing endurance sport is associated with reduced cardiac mortality. Endurance athletes are known to develop physiologic LV remodeling concomitant with increases in LV mass, which may be associated with QT prolongation. However, QT dynamics in middle-aged athletes has not been studied extensively. We sought to compare the QT interval at rest and during exercise in healthy middle-aged adults with and without a history of long-standing endurance exercise. Healthy participants on no medications, between 45-65 years old (>10 years of regular physical activity participation) were recruited, and underwent physical examination. Eligible participants, including 86 endurance athletes (EA) and 24 recreationally-active (RA) adults, had a resting baseline 12-lead ECG and a standardized graded exercise testing with a 12-lead ECG taken every 1-2 minutes during exercise until exhaustion. QT intervals were measured as the longest QT in anterior precordial lead or lead 2 by two investigators and discrepancies resolved by consensus; QT intervals were corrected for rate using Bazett’s formula (QTc=QT/√RR in sec). Seventy-five participants also had a resting cardiac magnetic resonance to evaluate cardiac structure and physiological remodeling related to exercise. Participant demographics and ECG characteristics are summarized in Table 1. The higher cardiorespiratory fitness (VO2max) and left-ventricular mass reflected normal physiological adaptation to endurance exercise training. While mean resting QT interval was longer in EA vs. RA, there was no difference when QT interval was corrected for heart rate (QTc). The QT and QTc slopes (linear relationship of QT vs. RR and QTc vs. RR during exercise) were not different between EA and RA. Among long-standing middle-aged athletes with normal physiologic remodeling, there is no difference in QT intervals in EA vs. RA when corrected for their lower resting heart rate. Despite physiologic LV remodelling, chronic endurance exercise training is associated with normal repolarization at rest and during exercise among middle-aged endurance athletes.

P4418Temporal analysis of leukocyte extravasation and morphological activation after standard cardiopulmonary exercise testing in patients with heart failure with reduced ejection fraction

Abstract Introduction Long-term exercise training reduces the systemic inflammatory load in patients with cardiovascular diseases. Acutely, however, an exercise challenge can trigger pro-inflammatory responses. The underlying cardiac syndrome might also influence the response of the adaptive and innate immune system to an acute exercise challenge. Purpose We compared the acute response to a standardized cardiopulmonary exercise test (CPET) in patients with heart failure with reduced ejection fraction (HFrEF) and age matched controls. Methods Patients with HFrEF (n=8; left ventricular ejection fraction [LVEF] ≤40%) and controls (n=9, LVEF ≥50%) participated in a CPET. Blood samples were taken before, immediately after and 2 hours after the test. Quantitative and morphological changes in leukocyte subpopulations, and formation of leukocyte-platelet aggregates were assessed in fresh blood samples by flow cytometry. Results are given as median and inter-quartile range (IQR). Results HFrEF (mean LVEF: 34%) and controls (mean LVEF: 57%) were 59 (range: 41 to 80) and 57 (range: 50 to 65) years old, respectively. In both groups acute exercise increased total leukocytes per mL of blood (control: 1.37-fold [IQR: 1.16 to 1.49]; HFrEF: 1.24-fold [IQR: 1.20 to 1.32]), relative abundance of circulating NK cells (controls: 2.11-fold [IQR: 1.30 to 3.13]; HFrEF: 1.67-fold [IQR: 1.56 to 1.71] and NK-T cells (control: 1.69-fold [IQR: 1.52 to 3.60]; HFrEF: 1.62-fold [IQR: 1.60 to 2.53]). Contrarily, only in HFrEF patients CD4+ (control: 1.15-fold [IQR: 0.84 to 1.54]; HFrEF: 1.45-fold [IQR: 1.10 to 1.98]) and CD8+ T cells (control: 1.33-fold [IQR: 1.01 to 1.68]; HFrEF: 1.70-fold [IQR: 1.25 to 2.15]) were augmented. Circulating monocyte and neutrophil numbers did not change in response to CPET. Aggregation of thrombocytes with monocytes (control: 0.86-fold [IQR: 0.78 to 1.49]; HFrEF: 1.59-fold [IQR: 1.05 to 7.30-fold]), T-lymphocytes (control: 1.27-fold [IQR: 1.05 to 1.68]; HFrEF: 1.49-fold [IQR: 1.03 to 2.64]) and neutrophils (control: 1.08-fold [IQR: 0.87 to 1.25]; HFrEF: 2.13-fold [IQR: 1.62 to 2.19]) increased 2 hour post-exercise in HFrEF patients, but not in controls. Conclusion Patients with HFrEF show a differential leukocyte response to an acute exercise challenge, with an increase in T-lymphocyte abundance, a degranulation response in the intermediate monocyte subpopulation and an increased formation of neutrophil-platelet-aggregates compared to control subjects. Our data suggest differences in release and organ-homing of innate versus adaptive immune cells, thus underlining the importance of inter-organ communication in the acute adaption to physical exertion in HFrEF.