Vitamin D and omega-3 polyunsaturated fatty acid supplementation in athletes with exercise-induced bronchoconstriction: a pilot study.

OBJECTIVE: The aim of this pilot study was to determine the combined effect of vitamin D and omega-3 polyunsaturated fatty acid (PUFA) supplementation on airway function and inflammation in recreational athletes with exercise-induced bronchoconstriction (EIB). METHODS: Ten recreational athletes with EIB participated in a single-blind, placebo-controlled trial over six consecutive weeks. All subjects attended the laboratory on three occasions. Each visit was separated by a period of 3 weeks: visit 1 (usual diet), visit 2 (placebo) and visit 3 (SMARTFISH® NutriFriend 2000; 30 µg vitamin D3-3000 mg eicosapentaenoic acid, 3000 mg docosahexaenoic acid) consumed once daily for a period of 3 weeks. Venous blood was collected at the beginning of each trial to determine vitamin D status. Spirometry was performed pre- and post-eucapnic voluntary hyperpnoea (EVH). RESULTS: The Maximum fall in FEV1 (ΔFEV1max) post-EVH was not different between visits (usual diet: -15.9 ± 3.6%, placebo: -16.1 ± 6.1%, vitamin D + omega-3 PUFA: -17.8 ± 7.2%). Serum vitamin D remained unchanged between visits. CONCLUSION: Vitamin D and omega-3 PUFA supplementation does not attenuate the reduction in lung function post-EVH. This finding should be viewed as preliminary until the results of randomised controlled trials are made available.

Exercise and inflammation-related epigenetic modifications: focus on DNA methylation.

Epigenetics is the study of mitotically or meiotically heritable phenotypes that occur as a result of modifications to DNA, thereby regulating gene expression independently of changes in base sequence due to manipulation of the chromatin structure. These modifications occur through a variety of mechanisms, such as DNA methylation, post-translational histone modifications, and non-coding RNAs, and can cause transcriptional suppression or activation depending on the location within the gene. Environmental stimuli, such as diet and exercise, are thought to be able to regulate these mechanisms, with inflammation as a probable contributory factor. Research into these areas is still in its infancy however. This review will focus on DNA methylation in the context of inflammation (both pro- and anti-inflammatory processes) and exercise. The complexity and relative shortcomings of some existing techniques for studying epigenetics will be highlighted, and recommendations for future study approaches made.

Salivary antimicrobial protein responses during multistage ultramarathon competition conducted in hot environmental conditions.

Prolonged strenuous exercise is commonly reported to depress oral-respiratory immune status and increase the incidence of upper respiratory symptoms. This novel investigation aimed to determine the salivary antimicrobial responses and hydration status of ultraendurance runners (n = 23) during a 230-km multistage ultramarathon conducted in hot ambient conditions (32-40 °C). Body mass was measured and unstimulated saliva and venous blood samples were taken before and after each stage of the ultramarathon. Ad libitum fluid intake was permitted throughout each race day. Upper respiratory symptoms were monitored during and until 4 weeks after race completion. Samples were analyzed for salivary immunoglobulin A (IgA), lysozyme, α-amylase, and cortisol, as well as for plasma and saliva osmolality. Mean exercise-induced body mass loss over the 5 stages ranged from 1.3% to 2.4%. Overall mean pre- and post-stage plasma osmolality measurements in the ultraendurance runners were 279 ± 14 mOsmol·kg(-1) and 293 ± 15 mOsmol·kg(-1), respectively. Decreases in saliva flow rate (overall change 22%) and post-stage increases in saliva osmolality (36%) were observed in the ultraendurance runners during the ultramarathon. Reduced salivary IgA (32%) (p < 0.001 vs. pre-stage salivary IgA), enhanced salivary α-amylase (187%) (p < 0.001 vs. pre-stage salivary α-amylase), and no change in salivary lysozyme secretion rates were observed in the ultraendurance runners throughout the ultramarathon. Only 1 ultraendurance runner reported upper respiratory symptoms during and 1 month after competition. Observed depressions in salivary IgA secretion rates were offset by favourable increases in salivary α-amylase and unchanged lysozyme responses in the majority of runners during the competition. Ensuring euhydration throughout a multistage ultramarathon competition in the heat may play a role in protecting the upper respiratory tract.

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.

Prevalence of allergy and upper respiratory tract symptoms in runners of the London marathon.

BACKGROUND: The prevalence of self-reported upper respiratory tract (URT) symptoms in athletes has been traditionally associated with opportunistic infection during the temporal suppression of immune function after prolonged exercise. There is little evidence for this, and a competing noninfectious hypothesis has been proposed, whereby the exercise-induced immune system modulations favor the development of atopy and allergic disease, which manifests as URT symptoms. The aim of this study was to examine the association between allergy and URT symptoms in runners after an endurance running event. METHODS: Two hundred eight runners from the 2010 London Marathon completed the validated Allergy Questionnaire for Athletes (AQUA) and had serum analyzed for total and specific immunoglobulin E response to common inhalant allergens. Participants who completed the marathon and nonrunning controls who lived in the same household were asked to complete a diary on URT symptoms. RESULTS: Forty percent of runners had allergy as defined by both a positive AQUA and elevated specific immunoglobulin E. Forty-seven percent of runners experienced URT symptoms after the marathon. A positive AQUA was a significant predictor of postmarathon URT symptoms in runners. Only 19% of nonrunning controls reported symptoms. CONCLUSIONS: The prevalence of allergy in recreational marathon runners was similar to that in elite athletes and higher than that in the general population. There was a strong association between a positive AQUA and URT symptoms. The low proportion of households in which both runners and nonrunners were symptomatic suggests that the nature of symptoms may be allergic or inflammatory based rather than infectious. Allergy is a treatable condition, and its potential effect on performance and health may be avoided by accurate clinical diagnosis and management. Both athletes' and coaches' awareness of the potential implications of poorly managed allergy needs to be raised.

Effect of volume of milk consumed on the attenuation of exercise-induced muscle damage.

Exercise-induced muscle damage (EIMD) leads to decrements in muscle performance, increases in intramuscular proteins and delayed-onset of muscle soreness (DOMS). Previous research demonstrated that one litre of milk-based protein-carbohydrate (CHO) consumed immediately following muscle damaging exercise can limit changes in markers of EIMD possibly due to attenuating protein degradation and/or increasing protein synthesis. If the attenuation of EIMD is derived from changes in protein metabolism then it can be hypothesised that consuming a smaller volume of CHO and protein will elicit similar effects. Three independent matched groups of 8 males consumed 500 mL of milk, 1,000 mL of milk or a placebo immediately following muscle damaging exercise. Passive and active DOMS, isokinetic muscle performance, creatine kinase (CK), myoglobin and interleukin-6 were assessed immediately before and 24, 48 and 72 h after EIMD. After 72 h 1,000 mL of milk had a likely benefit for limiting decrements in peak torque compared to the placebo. After 48 h, 1,000 mL of milk had a very likely benefit of limiting increases in CK in comparison to the placebo. There were no differences between consuming 500 or 1,000 mL of milk for changes in peak torque and CK. In conclusion, decrements in isokinetic muscle performance and increases in CK can be limited with the consumption of 500 mL of milk.

The prevalence and current opinion of treatment of allergic rhinitis in elite athletes.

PURPOSE: The aim of this review is to highlight the prevalence of allergic rhinitis in athletes and the impact this condition may have on their athletic performance. Furthermore, the optimal management of medical conditions in the elite athlete forms an important part of protecting the health of the athlete. RECENT FINDINGS: The use of pharmacological intervention in the treatment of allergic rhinitis in elite athletes requires careful planning. A variety of factors must be considered prior to prescription such as drug efficacy and safety both at rest and in conjunction with strenuous exercise, associated side effects on athletic performance and well being and whether the chosen drug is on the World Anti-Doping Agency (WADA) banned list. SUMMARY: Allergic rhinitis is common in elite athletes and may impair athletic performance and recovery. We advise that all elite and professional athletes should be screened for allergic rhinitis using validated questionnaire such as the Allergy Questionnaire for Athletes (AQUA) alongside skin prick testing or specific IgE blood tests for inhalant allergens. Intranasal corticosteroids are highly recommended as the management drug of choice for athletes in conjunction with second-generation antihistamines (severity dependant) and when practicable, allergen avoidance.

The effect of carbohydrate ingestion on plasma interleukin-6, hepcidin and iron concentrations following prolonged exercise.

The aim of our study was twofold, firstly to examine the relationship between plasma concentrations of IL-6, hepcidin and iron following prolonged exercise and secondly, to assess the effect of carbohydrate ingestion on circulating hepcidin concentration post-exercise. The study was a randomised double-blind cross-over design, with participants consuming either a carbohydrate (CHO) or an isovolumetric placebo drink throughout the trial. Nine healthy, trained males completed a treadmill run at 60% vVO(2max) for 120 min followed by a 5 km time trial. Plasma concentrations of both IL-6 and hepcidin significantly increased post-exercise following both trials (p<.05) and returned to baseline by 24 h post (p>.05). A positive correlation between hepcidin and IL-6 was demonstrated immediately following exercise during PLA while there was a trend for a moderate correlation during CHO (PLA trial rho=0.81, p<0.001; CHO trial rho=0.36, p=0.07). Plasma iron was unaffected immediately post-exercise but significantly reduced by 24 h post-exercise compared to baseline. CHO ingestion significantly reduced post-exercise IL-6 (p<.05) but this had no effect on plasma hepcidin or iron concentration. Our data demonstrate CHO supplementation does not alter the rapid hepcidin response associated with exercise and does not prevent a subsequent fall in plasma iron concentration. This finding adds further support to the theory that an exercise-induced, up-regulation of hepcidin activity is a mechanism causing iron deficiency in endurance athletes.

The effect of exercise on plasma soluble IL-6 receptor concentration: a dichotomous response.

The aim of this article is to review current literature on the response of soluble interleukin-6 receptor to exercise and identify a potential role for sIL-6R in skeletal muscle function. We also provide novel data on the impact of eccentric exercise on circulating levels. The aim of the research study was to investigate changes in plasma concentration of soluble interleukin-6 receptor (sIL-6R) and soluble glycoprotein 130 (sgp130) during recovery from exercise-induced muscle damage (EIMD) up to 72 h and their relationship with delayed onset muscle soreness (DOMS) and muscle function. 18 participants attended the laboratory on 4 consecutive days. On the first day, participants completed 6 sets of 10 repetitions of unilateral eccentric-concentric knee flexions at a test speed of 1.05 rad.s(-1) using a Cybex Isokentic dynamometer to induce muscle damage of the hamstrings. Prior to the eccentric exercise bout and each subsequent morning, following an overnight fast, participants had a venous blood sample taken which was centrifuged immediately and plasma frozen at -80 degrees C until later analysis. Plasma IL-6 and sgp130 were unchanged at any time point during recovery but sIL-6R was significantly reduced at 48 h and 72 h post-exercise (p < 0.05). Plasma sIL-6R was correlated with DOMS at 48 h post EIMD (r = 0.45, p < 0.05) and peak muscle torque at 24 h and 48 h following EIMD (r = -.42; p < 0.05; r = -.57; p < 0.01 respectively). Our novel finding that sIL-6R concentrations are decreased 2-3 days following a single bout of EIMD may reflect a regulatory mechanism controlling the influx of different leukocyte subpopulations into damaged tissue, although this needs to be confirmed by future studies. Our data suggests an association between sIL-6R, perception of pain and reduced peak muscle performance post-EIMD but further investigation is warranted to explore this relationship and implications for exercise performance.

Pathophysiology, diagnosis and management of exercise-induced anaphylaxis.

PURPOSE OF REVIEW: The aim of this review is to challenge the current opinions of the pathophysiological mechanisms that give rise to food dependent exercise-induced anaphylaxis (FDEIA) and to consider these mechanisms within the wider context of exercise physiology to further inform our understanding and treatment of this condition. RECENT FINDINGS: Exercise-induced anaphylaxis (food dependent and nonfood dependent) is a clinical syndrome in which anaphylaxis occurs in conjunction with exercise. Given the rarity of the condition, our current understanding relies on the many case studies and reviews of the topic. The pathophysiology of FDEIA remains to be fully elucidated with well constructed trials but current working hypotheses to date involve alterations in plasma osmolaltiy and pH, tissue enzyme activity, blood flow redistribution, altered gastrointestinal permeability and facilitated epitope recognition/allergen binding. SUMMARY: Implications for future research are the physiological changes that occur during exercise need deeper consideration to ensure that proposed mechanisms are realistic and actually occur within the time frame and exercise-intensity domain during which the reported FDEIA occurred. These theories must be tested rigorously with sufficiently powered studies if progress is to be made in determining the perplexing pathophysiology of FDEIA.

Effect of milk-based carbohydrate-protein supplement timing on the attenuation of exercise-induced muscle damage.

Exercise-induced muscle damage (EIMD) leads to decrements in muscle performance and increases in intramuscular enzymes measured in the plasma, and to delayed onset of muscle soreness (DOMS), partly due to the activation of degradative pathways. It has been shown that milk-based carbohydrate-protein (CHO-P) can limit changes in markers of EIMD, possibly by attenuating protein degradation and (or) increasing protein synthesis. However, the timing of supplementation has received limited attention, and this may alter the response. This study examined the effects of acute milk-based CHO-P supplementation timing on the attenuation of EIMD. Four independent matched groups of 8 healthy males consumed milk-based CHO-P before (PRE), immediately after (POST), or 24 h after (TWENTY-FOUR) muscle-damaging exercise. Active DOMS, isokinetic muscle performance, reactive strength index (RSI), and creatine kinase (CK) were assessed immediately before and 24, 48, and 72 h after EIMD. POST and TWENTY-FOUR demonstrated a benefit in limiting changes in active DOMS, peak torque, and RSI over 48 h, compared with PRE. PRE showed a possible benefit in reducing increases in CK over 48 h and limiting changes in other variables over 72 h. Consuming milk-based CHO-P after muscle-damaging exercise is more beneficial in attenuating decreases in muscle performance and increases in active DOMS at 48 h than ingestion prior to exercise.

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(-1) and 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.

Fatigue management in the preparation of Olympic athletes.

Fatigue is often a consequence of physical training and the effective management of fatigue by the coach and athlete is essential in optimizing adaptation and performance. In this paper, we explore a range of practical and contemporary methods of fatigue management for Olympic athletes. We assesses the scientific merit of methods for monitoring fatigue, including self-assessment of training load, self-scored questionnaires, and the usefulness of saliva and blood diagnostic markers for indicating fatigued and under-recovered athletes, effective nutrition and hydration strategies for optimizing recovery and short-term recovery methods. We conclude that well-accepted methods such as sufficient nutrition, hydration, and rest appear to be the most effective strategies for optimizing recovery in Olympic athletes.

The effect of repeated endurance exercise on IL-6 and sIL-6R and their relationship with sensations of fatigue at rest.

Strenuous, prolonged exercise increases interleukin-6 (IL-6) release. The effect of IL-6 is dependent on the availability of IL-6 receptors. Few studies have addressed the impact of exercise on IL-6 receptor levels or procalcitonin (PCT), an indicator of systemic inflammation. Changes in these molecules may give insight into cytokine-related mechanisms underlying exercise-related fatigue. Thirteen trained male subjects partook in the study. They cycled a total distance of 468 km over 6 days. Blood samples were obtained prior to and immediately following Day 1 of the study and then each morning prior to exercise. Blood samples were analysed for plasma IL-6, soluble IL-6 receptor (sIL-6R), C-reactive protein (CRP), PCT, creatine kinase (CK) and cortisol concentrations. Subjects also completed mood state questionnaires each day prior to exercise. IL-6 was elevated immediately post-exercise on Day 1 but was unchanged at rest for the duration of the event. In contrast, sIL-6R, CRP, PCT and CK concentrations were unchanged immediately post-exercise on Day 1 but were significantly elevated at rest over the duration of the event compared with pre-event baseline. sIL-6R was highly correlated to CRP. Cortisol concentrations remained unchanged at all time points. In conclusion, strenuous, prolonged exercise stimulated an acute phase response which was maintained throughout the 6-day event. sIL-6R increase is associated with CRP and may affect subjective sensations of post-exercise fatigue at rest.

Elevated plasma interleukin-6 levels in trained male triathletes following an acute period of intense interval training.

The aim of the present study was to investigate possible changes in the plasma IL-6 levels, subjective reporting of sources and symptoms of stress and the innate immune system in response to an acute period of intensified run training in highly trained endurance athletes. Eight healthy endurance trained male subjects (mean +/- SD age 23 +/- 2 years, VO(2max) 64.8 +/- 2.6 ml kg(-1) min(-1), mass 77.1 +/- 2.9 kg) completed the study which took place over a 4 week period. In weeks 2 and 3, in addition to their normal endurance training, subjects completed interval-training run sessions on three successive days. Saliva and venous blood samples were taken at the end of each week. Blood samples were analysed for leukocyte counts; neutrophil function; plasma IL-6; creatine kinase activity; and cortisol. Symptoms and sources of stress were assessed by questionnaire. Plasma IL-6 and creatine kinase activity were elevated following intensified training. Neutrophil function was reduced but total leukocyte and neutrophil counts, plasma cortisol and salivary IgA remained unchanged. There was a worsening in symptoms of stress despite there being no significant change in the sources of stress during intensified training. In conclusion, an acute period of intensified training can induce a suppression of the innate immune system and a chronic elevation in IL-6. This was associated with an increase in fatigue and generalised malaise which lends support to the recent cytokine theories of unexplained, underperformance syndrome.

Acute interleukin-6 administration impairs athletic performance in healthy, trained male runners.

Fatigue is an inevitable consequence of physical activity; yet its biological cause remains uncertain. During exercise, a polypeptide messenger molecule interleukin-6 (IL-6) is actively produced. Previously, the administration of recombinant IL-6 (rhIL-6) induced a heightened sensation of fatigue in healthy humans at rest. In contrast, anti-IL-6 receptor antibodies reduced the symptoms of chronic fatigue. In the present study, athletic performance during an exercise challenge consisting of a 10-km running time trial was significantly impaired in trained male runners following the administration of a low dose of rhIL-6 compared to the placebo trial.