The effect of carbohydrate ingestion on the Interleukin-6 response to a 90-minute run time trial

Fatigue is a predictable outcome of prolonged physical activity; yet its biological cause remains uncertain. During exercise, a polypeptide messenger molecule interleukin- 6 (IL-6) is actively produced. Previously, it has been demonstrated that administration of recombinant IL-6 (rhIL-6) impairs 10-km run performance and heightened sensation of fatigue in trained runners. Both high carbohydrate diets and carbohydrate ingestion during prolonged exercise have a blunting effect on IL-6 levels postendurance exercise. We hypothesized that carbohydrate ingestion may improve performance during a prolonged bout of exercise as a consequence of a blunted IL-6 response. Seven recreationally trained fasted runners completed two 90-min time trials under CHO supplemented and placebo conditions in a randomized order. The study was of a double-blinded, placebo-controlled, cross-over study design. Distance covered in 90 min was significantly greater following exogenous carbohydrate ingestion compared with the placebo trial (19.13 ± 1.7 km and 18.29 ± 1.9 km, respectively, p = .0022). While postexercise IL-6 levels were significantly lower in the CHO trial compared with the placebo trial (5.3 ± 1.9 pg·mL?1and 6.6 ± 3.0 pg·mL?1, respectively; p = .0313), this difference was considered physiologically too small to mediate the improvement in time trial performance

Grouping of decathlon disciplines

The 10 disciplines in the decathlon can be broadly characterised as running, jumping and throwing. However, these simplistic characteristics may not represent the groupings defined by performances in the decathlon. The identification of groups may reveal a recondite advantage for athletes who excel in particular disciplines. Therefore this study used cluster analysis to determine the groupings inherent within the decathlon disciplines. The data set was derived from the top 173 decathletes between the years 1986 to 2005. Six clustering methods were applied to a Euclidean proximity matrix. The highest number of clusters common to all the methods was accepted as the solution. All six methods produced the same 3-cluster ([100m 400m 110H LJ PV HJ][SP DT JT][1500m]), 4-cluster ([100m 400m 110H LJ PV][SP DT JT][HJ][1500m]) and 5-cluster ([100m 400m 110mH LJ][SP DT JT][PV][HJ][1500m]) solutions. Stability tests confirmed the consistency of all the solutions. The 10 disciplines of the decathlon form into five groupings, which can be adequately explained from a physiological perspective. The clustering suggests that athletes who perform better at the sprint/track disciplines may obtain an advantage in the decathlon

Exercise-Conditioned Plasma and DNMT3B Concentration in PBMCs

DNA methylation is modifiable by acute and chronic exercise. DNA methyltransferases (DNMT) catalyze this process; however, there is a lack of literature concerning the specific mechanisms by which exercise‐induced modifications occur. Interleukin 6 (IL‐6) stimulation of various cell lines has been shown to augment DNMT expression and nuclear translocation, which suggests a possible pathway by which exercise is able to elicit changes in epigenetic enzymes. The present study sought to elucidate the response of thede novomethyltransferases DNMT3A and DNMT3B to circulatory factors found in plasma isolated from whole blood before and after 120‐min of treadmill running at an intensity of 60% of individual velocity at(v) interspersed with 30‐sec sprints at 90% of vevery 10‐min. Peripheral blood mononuclear cells (PBMCs) isolated from a resting participant were incubated with plasma isolated from exercising participants (n=10) or recombinant IL‐6 (rIL‐6), followed by nuclear protein extraction and quantification of DNMT3A and DNMT3B concentrations. Nuclear concentrations of DNMT3B significantly decreased following the experimental protocol (P=0.03), with no change observed in DNMT3A (P=0.514).Various concentrations of rIL‐6 caused an elevation in both DNMT3A and DNMT3B nuclear concentration compared with the blank control. The conflicting results between exercising and rIL‐6 conditions suggests that IL‐6 does regulate DNMT nuclear transport, however, other plasma mediators may also exert significant influence on the nuclear concentrations of these enzymes

Central & peripheral fatigue in male cyclists after 4, 20 & 40 km time-trials

Purpose: Few studies have assessed neuromuscular fatigue after self-paced locomotor exercise; moreover, none have assessed the degree of supraspinal fatigue. This study assessed central and peripheral fatigue after self-paced exercise of different durations. Methods: Thirteen well-trained male cyclists completed 4 km, 20 km and 40 km simulated time-trials (TTs). Pre- and immediately post-TT (30 min)

Exercise-induced bronchoconstriction in athletes – A qualitative assessment of symptom perception

© 2016Background A poor relationship between perceived respiratory symptoms and objective evidence of exercise-induced bronchoconstriction (EIB) in athletes is often reported; however, the reasons for this disconnect remain unclear. The primary aim of this study was to utilise a qualitative-analytical approach to compare respiratory symptoms in athletes with and without objectively confirmed EIB. Methods Endurance athletes who had previously undergone bronchoprovocation test screening for EIB were divided into sub-groups, based on the presence or absence of EIB ± heightened self-report of dyspnoea: (i) EIB-Dys- (ii) EIB + Dys+ (iii) EIB + Dys- (iv) EIB-Dys+. All athletes underwent a detailed semi-structured interview. Results Twenty athletes completed the study with an equal distribution in each sub-group (n = 5). Thematic analysis of individual narratives resulted in four over-arching themes: 1) Factors aggravating dyspnoea, 2) Exercise limitation, 3) Strategies to control dyspnoea, 4) Diagnostic accuracy. The anatomical location of symptoms varied between EIB + Dys + athletes and EIB-Dys + athletes. All EIB-Dys + reported significantly longer recovery times following high-intensity exercise in comparison to all other sub-groups. Finally, EIB + Dys + reported symptom improvement following beta-2 agonist therapy, whereas EIB-Dys + deemed treatment ineffective. Conclusion A detailed qualitative approach to the assessment of breathlessness reveals few features that distinguish between EIB and non-EIB causes of exertional dyspnoea in athletes. Important differences that may provide value in clinical work-up include (i) location of symptoms, (ii) recovery time following exercise and (iii) response to beta-2 agonist therapy. Overall these findings may inform clinical evaluation and development of future questionnaires to aid clinic-based assessment of athletes with dyspnoea

Eucapnic Voluntary Hyperpnea: Gold Standard for Diagnosing Exercise-Induced Bronchoconstriction in Athletes?

In athletes, a secure diagnos is of exercise-induced bronchoconstriction (EIB) is dependent on objective testing. Evaluating spirometric indices of airflow before and following an exercise bout is intuitively the optimal means for the diagnosis; however, this approach is recognized as having several key limitations. Accordingly, alternative indirect bronchoprovocation tests have been recommended as surrogate means for obtaining a diagnosis of EIB. Of these tests, it is often argued that the eucapnic voluntary hyperpnea (EVH) challenge represents the ‘gold standard’. This article provides a state-of-the-art review of EVH, including an overview of the test methodology and its interpretation. We also address the performance of EVH against the other functional and clinical approaches commonly adopted for the diagnosis of EIB. The published evidence supports a key role for EVH in the diagnostic algorithm for EIB testing in athletes. However, its wide sensitivity and specificity and poor repeatability preclude EVH from being termed a ‘gold standard’ test for EIB

Coyrab Version I

Background - In athletic individuals, a secure diagnosis of exercise-induced bronchoconstriction (EIB) is dependent on objective testing. Indirect bronchoprovocation testing is often used in this context and eucapnic voluntary hyperpnea (EVH) testing is recommended for this purpose, yet the short-term reproducibility of EVH is yet to be appropriately established. Objective - The aim of this study was to evaluate the reproducibility of EVH in a cohort of recreational athletes. Methods - A cohort of recreational athletes (n = 32) attended the laboratory on two occasions to complete an EVH challenge, separated by a period of 14 or 21 days. Spirometry and impulse oscillometry was performed before and after EVH. Training load was maintained between visits. Results - Prechallenge lung function was similar at both visits (P > .05). No significant difference was observed in maximum change in FEV1 (ΔFEV1max) after EVH between visits (P > .05), and test-retest ΔFEV1max was correlated (intraclass correlation coefficient = 0.81; r2 = 0.66; P = .001). Poor diagnostic reliability was observed between tests; 11 athletes were diagnosed with EIB (on the basis of ΔFEV1max ≥10%) at visit 1 and at visit 2. However, only 7 athletes were positive at both visits. Although there was a small mean difference in ΔFEV1max between tests (−0.6%), there were wide limits of agreement (−10.7% to 9.5%). Likewise, similar results were observed for impulse oscillometry between visits. Conclusions - In a cohort of recreational athletes, EVH demonstrated poor clinical reproducibility for the diagnosis of EIB. These findings highlight a need for caution when confirming or refuting EIB on the basis of a single indirect bronchoprovocation challenge. When encountering patients with mild or borderline EIB, we recommend that more than one EVH test is performed to exclude or confirm a diagnosis

Human Tissue Act: implications for sports science

In September 2006, an Act with significant implications for sports science research conducted in the UK came into force. The Human Tissue (HT) Act replaced the previous version of 1961 and affects all scientific practice that involves human tissue sampling and storage.1 The HT Act was conceived in response to shortcomings revealed in a series of public inquiries into UK hospital practice over the past 25 years;2 3 in particular, to address the use of human tissue and organs without appropriate patient consent. Consequently, its purpose is to provide a new legal framework for the acquisition, analysis and storage of human tissue in England, Wales and Northern Ireland. In order to implement this Act, a special authority (the Human Tissue Authority; HTA) was also established. Since inception, the Act has had significant implications for both clinical and research practice in the UK.4 5 Indeed, although the Act primarily concerns pathological specimens, it affects all practice that involves human tissue sampling. This is particularly true in sports science, where collection, storage and analysis of human samples are fundamental to many studies

Managing respiratory problems in athletes

Respiratory problems are common in athletes of all abilities and can significantly impact upon their health and performance. In this article, we provide an overview of respiratory physiology in athletes. We also discuss the assessment and management of common clinical respiratory conditions as they pertain to athletes, including airways disease, respiratory tract infection and pneumothorax. We focus on providing a pragmatic approach and highlight important caveats for the physician treating respiratory conditions in this highly specific population