Special feature for the Olympics: effects of exercise on the immune system: infections and exercise in high-performance athletes

Physical activity, acute severity and long-term consequences of COVID-19: an 18-month follow-up survey based on a Swedish national cohort

OBJECTIVE

To investigate how changes in levels of physical activity (PA) in regard to acute disease severity relate to perceived difficulties in performing daily life activities 18 months after COVID-19 infection.

DESIGN

An observational study with an 18-month follow-up survey based on registry data from a national cohort.

PARTICIPANTS

5464 responders to the 18-month follow-up survey of a Swedish national cohort of 11 955 individuals on sick leave due to COVID-19 during the first wave of the pandemic.

OUTCOMES

The follow-up survey included questions on daily life activities, as well as present and retrospective level of PA. Changes in PA level from before COVID-19 to follow-up were assessed by the Saltin-Grimby PA Level Scale and analysed by the Wilcoxon signed-rank test. Comparisons of groups were analysed by the Student's t-test, Mann-Whitney U test and χ2. Multiple binary logistic regression was performed to assess the association of changes in PA with perceived difficulties in performing daily life activities.

RESULTS

Among the 5464 responders (45% of national cohort), the PA level decreased. Hospitalised individuals had a lower PA level both prior to COVID-19 (p=0.035) and at the 18-month follow-up (p=0.008) compared with non-hospitalised responders. However, the level of PA decreased in both groups. A decrease in PA level increased the odds (OR 5.58, 95% CI 4.90 to 6.34) of having difficulties performing daily life activities.

CONCLUSIONS

PA levels were reduced 18 months after COVID-19 infection. A decrease in PA over that time was associated with perceived difficulties performing daily life activities 18 months after COVID-19. As PA is important in maintaining health and deconditioning takes time to reverse, this decline may have long-term implications for PA and health.

Immunological Response to Exercise in Athletes with Disabilities: A Narrative Review of the Literature

For a person with a disability, participating in sports activities and/or competitions can be a challenge for the immune system. The relationship between exercise and immunity response in disabled athletes is, indeed, extremely complex for several reasons, including (1) the chronic low-grade inflammatory and immunodepression-"secondary immune deficiency"-state imposed by the disability/impairment; (2) the impact of the disability on an array of variables, spanning from physical fitness to well-being, quality of life, sleep, and nutritional aspects, among others, which are known to mediate/modulate the effects of exercise on human health; (3) the variability of the parameters related to the exercise/physical activity (modality, frequency, intensity, duration, training versus competition, etc.); and (4) the intra- and inter-individual variability of the immunological response to exercise. In able-bodied athletes, previously published data described several exercise-induced changes affecting various immunological subsets and subpopulations, ranging from neutrophils to lymphocytes, and monocytes. Broadly, moderate intensity workout is accompanied by optimal immunity and resistance to infections such as upper respiratory tract infections (URTI) in athletes. Periods of intense training with insufficient recovery can cause a temporary state of immunosuppression, which should end with a few days of rest/recovery from exercise. Disabled athletes are relatively overlooked and understudied with respect to their able-bodied counterparts. Findings from the few studies available on paralympic and disabled athletes are here summarized and analyzed utilizing a narrative approach to review and determine the major features of the immunological and inflammatory responses to exercise in this specific population. Moreover, a few studies have reported behavioral, dietary, and training strategies that can be adopted to limit exercise-induced immunosuppression and reduce the risk of infection in people with disabilities. However, given the paucity of data and contrasting findings, future high-quality investigations on paralympic and disabled athletes are urgently needed.

Wearable technology in the sports medicine clinic to guide the return-to-play and performance protocols of athletes following a COVID-19 diagnosis

The coronavirus disease 2019 (COVID-19) pandemic has enabled the adoption of digital health platforms for self-monitoring and diagnosis. Notably, the pandemic has had profound effects on athletes and their ability to train and compete. Sporting organizations worldwide have reported a significant increase in injuries manifesting from changes in training regimens and match schedules resulting from extended quarantines. While current literature focuses on the use of wearable technology to monitor athlete workloads to guide training, there is a lack of literature suggesting how such technology can mediate the return to sport processes of athletes infected with COVID-19. This paper bridges this gap by providing recommendations to guide team physicians and athletic trainers on the utility of wearable technology for improving the well-being of athletes who may be asymptomatic, symptomatic, or tested negative but have had to quarantine due to a close exposure. We start by describing the physiologic changes that occur in athletes infected with COVID-19 with extended deconditioning from a musculoskeletal, psychological, cardiopulmonary, and thermoregulatory standpoint and review the evidence on how these athletes may safely return to play. We highlight opportunities for wearable technology to aid in the return-to-play process by offering a list of key parameters pertinent to the athlete affected by COVID-19. This paper provides the athletic community with a greater understanding of how wearable technology can be implemented in the rehabilitation process of these athletes and spurs opportunities for further innovations in wearables, digital health, and sports medicine to reduce injury burden in athletes of all ages.

COVID-19 and elite sport: Cardiovascular implications and return-to-play

Curtailing elite sports during the coronavirus disease 2019 (COVID-19) pandemic was necessary to prevent widespread viral transmission. Now that elite sport and international competitions have been largely restored, there is still a need to devise appropriate screening and management pathways for athletes with a history of, or current, COVID-19 infection. These approaches should support the decision-making process of coaches, sports medicine practitioners and the athlete about the suitability to return to training and competition activities. In the absence of longitudinal data sets from athlete populations, the incidence of developing prolonged and debilitating symptoms (i.e., Long COVID) that affects a return to training and competition remains a challenge to sports and exercise scientists, sports medicine practitioners and clinical groups. As the world attempts to adjust toward 'living with COVID-19' the very nature of elite and international sporting competition poses a risk to athlete welfare that must be screened for and managed with bespoke protocols that consider the cardiovascular implications for performance.

International Olympic Committee (IOC) consensus statement on acute respiratory illness in athletes part 1: acute respiratory infections

Acute illnesses affecting the respiratory tract are common and form a significant component of the work of Sport and Exercise Medicine (SEM) clinicians. Acute respiratory illness (ARill) can broadly be classified as non-infective ARill and acute respiratory infections (ARinf). The aim of this consensus is to provide the SEM clinician with an overview and practical clinical approach to ARinf in athletes. The International Olympic Committee (IOC) Medical and Scientific Commission appointed an international consensus group to review ARill (non-infective ARill and ARinf) in athletes. Six subgroups of the IOC Consensus group were initially established to review the following key areas of ARill in athletes: (1) epidemiology/risk factors for ARill, (2) ARinf, (3) non-infective ARill including ARill due to environmental exposure, (4) acute asthma and related conditions, (5) effects of ARill on exercise/sports performance, medical complications/return-to-sport and (6) acute nasal/vocal cord dysfunction presenting as ARill. Several systematic and narrative reviews were conducted by IOC consensus subgroups, and these then formed the basis of sections in the consensus documents. Drafting and internal review of sections were allocated to 'core' members of the consensus group, and an advanced draft of the consensus document was discussed during a meeting of the main consensus core group in Lausanne, Switzerland on 11 to 12 October 2021. Final edits were completed after the meeting. This consensus document (part 1) focusses on ARinf, which accounts for the majority of ARill in athletes. The first section of this consensus proposes a set of definitions and classifications of ARinf in athletes to standardise future data collection and reporting. The remainder of the consensus paper examines a wide range of clinical considerations related to ARinf in athletes: epidemiology, risk factors, pathology/pathophysiology, clinical presentation and diagnosis, management, prevention, medical considerations, risks of infection during exercise, effects of infection on exercise/sports performance and return-to-sport guidelines.

The effects of acute respiratory illness on exercise and sports performance outcomes in athletes - a systematic review by a subgroup of the IOC consensus group on "Acute respiratory illness in the athlete"

Acute respiratory infections (ARinf) are common in athletes, but their effects on exercise and sports performance remain unclear. This systematic review aimed to determine the acute (short-term) and longer-term effects of ARinf, including SARS-CoV-2 infection, on exercise and sports performance outcomes in athletes. Data sources searched included PubMed, Web of Science, and EBSCOhost, from January 1990-31 December 2021. Eligibility criteria included original research studies published in English, measuring exercise and/or sports performance outcomes in athletes/physically active/military aged 15-65years with ARinf. Information regarding the study cohort, diagnostic criteria, illness classification, and quantitative data on the effect on exercise/sports performance were extracted. Database searches identified 1707 studies. After full text screening, 17 studies were included (n = 7793). Outcomes were acute or longer-term effects on exercise (cardiovascular or pulmonary responses), or sports performance (training modifications, change in standardised point scoring systems, running biomechanics, match performance or ability to start/finish an event). There was substantial methodological heterogeneity between studies. ARinf was associated with acute decrements in sports performance outcomes (4 studies) and pulmonary function (3 studies), but minimal effects on cardiorespiratory endurance (7 studies in mild ARinf). Longer-term detrimental effects of ARinf on sports performance (6 studies) were divided. Training mileage, overall training load, standardised sports performance-dependent points and match play can be affected over time. Despite few studies, there is a trend towards impairment in acute and longer-term exercise and sports outcomes after ARinf in athletes. Future research should consider a uniform approach to explore relationships between ARinf and exercise/sports performance.

Respiratory Viral Infections in Athletes: Many Unanswered Questions

Upper respiratory tract infections (“common cold”) are the most common acute illnesses in elite athletes. Numerous studies on exercise immunology have proposed that intense exercise may increase susceptibility to respiratory infections. Virological data to support that view are sparse, and several fundamental questions remain. Immunity to respiratory viral infections is highly complex, and there is a lack of evidence that minor short- or long-term alterations in immunity in elite athletes have clinical implications. The degree to which athletes are infected by respiratory viruses is unclear. During major sport events, athletes are at an increased risk of symptomatic infections caused by the same viruses as those in the general population. The symptoms are usually mild and self-limiting. It is anecdotally known that athletes commonly exercise and compete while having a respiratory viral infection; there are no virological studies to suggest that such activity would affect either the illness or the performance. The risk of myocarditis exists. Which simple mitigation procedures are crucial for effective control of seasonal respiratory viral infections is not known.

A Guide to Different Intensities of Exercise, Vaccination, and Sports Nutrition in the Course of Preparing Elite Athletes for the Management of Upper Respiratory Infections during the COVID-19 Pandemic: A Narrative Review

Elite athletes use high-intensity training to maintain their fitness level. However, intense training can harm the immune system, making athletes suspectable to COVID-19 and negatively affecting their performance. In addition, the diet of athletes should be appreciated more as it is another influencer of the immune system, especially during the COVID 19 pandemic. The other important issue elite athletes face currently is vaccination and its possible intervention with their training. The present study attempts to discuss the impact of different training intensities, nutritional strategies, and vaccination on the immune system function in elite athletes. To this end, Scopus, ISC, PubMed, Web of Science, and Google Scholar databases were searched from 1988 to 2021 using the related keywords. The results of our review showed that although high-intensity exercise can suppress the immune system, elite athletes should not stop training in the time of infection but use low- and moderate-intensity training. Moderate-intensity exercise can improve immune function and maintain physical fitness. In addition, it is also better for athletes not to undertake high-intensity training at the time of vaccination, but instead perform moderate to low-intensity training. Furthermore, nutritional strategies can be employed to improve immune function during high-intensity training periods.

Health care professionals' understanding of contraindications for physical activity advice in the setting of stem cell transplantation

PURPOSE

Most patients receiving a hematopoietic stem cell transplantation (HSCT) are able to tolerate and benefit from physical activity (PA). Therefore, it is important that health care professionals (HCPs) advise patients to perform PA before, during, and after transplantation. By understanding which medical conditions and safety issues are associated with the (non-) promotion of PA, concrete actions and interventions can be planned and implemented.

METHODS

Physicians (N = 51), nurses (N = 52), and physical therapists (N = 26) participated in a nationwide cross-sectional online survey. HCPs' understanding of 15 medical conditions as contraindications for PA was assessed. Significant group differences were determined using chi-square analysis.

RESULTS

Acute infection was the only condition which was considered as contraindication by all HCPs (62.7%). Cachexia (78%), having a stoma (91%), or port (96.2%), psychological problems (88.4%), and leukopenia (83.3%) were not considered as contraindications. Six conditions were rated inconsistently between the groups, whereas physicians had the least concerns regarding PA. Physicians with an additional training in PA perceived a platelet count of ≤ 50,000/μl significantly less often as contraindication (p < 0.05).

CONCLUSION

The large number of potentially-answers especially in nursing staff and physical therapists might reflect caution or uncertainty. There is a clear need for a good multidisciplinary cooperation between all HCPs in order to support patients to confidently engage in PA. Furthermore, education possibilities and evidence-based courses to build knowledge regarding safety concerns should be the standard practice in the setting of HSCT. The investigative nature of the paper indicates that certain trends should be interrogated in a causal-longitudinal design.

Illness prevalence and symptoms in youth floorball players: a one-season prospective cohort study involving 471 players

OBJECTIVE

To describe weekly illness prevalence and illness symptoms by sex in youth floorball players during one season.

DESIGN

Prospective cohort study.

SETTING

Players who were registered to play community level floorball during the 2017-2018 season (26 weeks) in two provinces in southern Sweden.

PARTICIPANTS

471 youth players aged 12-17 years. Mean (SD) age for 329 male players 13.3 (1.0) years and 142 female players 13.7 (1.5) years.

PRIMARY AND SECONDARY OUTCOME MEASURES

Weekly self-reported illness prevalence and illness symptoms according to the 2020 International Olympic Committee's consensus recommendations.

RESULTS

61% of youth floorball players reported at least one illness week during the season, with an average weekly illness prevalence of 12% (95% CI 10.8% to 12.3%). The prevalence was slightly higher among females (13%, 95% CI 11.6% to 14.3%) than males (11%, 95% CI 9.9% to 11.7%), prevalence rate ratio 1.20 (95% CI 1.05 to 1.37, p=0.009). In total, 49% (53% male, 43% female) of illness reports indicated that the player could not participate in floorball (time loss), with a mean (SD) absence of 2.0 (1.7) days per illness week. Fever (30%), sore throat (16%) and cough (14%) were the most common symptoms. Female players more often reported difficulty in breathing/tight airways and fainting, and male players more often reported coughing, feeling tired/feverish and headache. Illness prevalence was highest in the peak winter months (late January/February) reaching 15%-18% during this period.

CONCLUSIONS

Our novel findings of the illness prevalence and symptoms in youth floorball may help direct prevention strategies. Athletes, coaches, parents and support personnel need to be educated about risk mitigation strategies.

TRIAL REGISTRATION NUMBER

NCT03309904.

Acute respiratory illness and return to sport: a systematic review and meta-analysis by a subgroup of the IOC consensus on 'acute respiratory illness in the athlete'

OBJECTIVE

To determine the days until return to sport (RTS) after acute respiratory illness (ARill), frequency of time loss after ARill resulting in >1 day lost from training/competition, and symptom duration (days) of ARill in athletes.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, EBSCOhost, Web of Science, January 1990-July 2020.

ELIGIBILITY CRITERIA

Original research articles published in English on athletes/military recruits (15-65 years) with symptoms/diagnosis of an ARill and reporting any of the following: days until RTS after ARill, frequency (%) of time loss >1 day after ARill or symptom duration (days) of ARill.

RESULTS

767 articles were identified; 54 were included (n=31 065 athletes). 4 studies reported days until RTS (range: 0-8.5 days). Frequency (%) of time loss >1 day after ARill was 20.4% (95% CI 15.3% to 25.4%). The mean symptom duration for all ARill was 7.1 days (95% CI 6.2 to 8.0). Results were similar between subgroups: pathological classification (acute respiratory infection (ARinf) vs undiagnosed ARill), anatomical classification (upper vs general ARill) or diagnostic method of ARinf (symptoms, physical examination, special investigations identifying pathogens).

CONCLUSIONS

In 80% of ARill in athletes, no days were lost from training/competition. The mean duration of ARill symptoms in athletes was 7 days. Outcomes were not influenced by pathological or anatomical classification of ARill, or in ARinf diagnosed by various methods. Current data are limited, and future studies with standardised approaches to definitions, diagnostic methods and classifications of ARill are needed to obtain detailed clinical, laboratory and specific pathogen data to inform RTS.

PROSPERO REGISTRATION NUMBER

CRD42020160479.

Utilizing Heart Rate Variability for Coaching Athletes During and After Viral Infection: A Case Report in an Elite Endurance Athlete

Background: Viral diseases have different individual progressions and can lead to considerable risks/long-term consequences. Therefore, it is not suitable to give general recommendations on a time off from training for athletes. This case report aims to investigate the relevance of detecting heart rate (HR) and HR variability (HRV) during an orthostatic test (OT) to monitor the progression and recovery process during and after a viral disease in an elite endurance athlete.

Methods: A 30-year-old elite marathon runner contracted a viral infection (upper respiratory tract infection) 4 weeks after a marathon race. RR intervals in HR time series in supine and standing positions were monitored daily in the morning. Analyzed parameters included HR, the time-domain HRV parameter root mean square of successive difference (RMSSD), peak HR (HRpeak) in a standing position, and the time to HR peak (tHRpeak).

Results: During the 6-day viral infection period, HR increased significantly by an average of 11 bpm in the supine position and by 22 bpm in the standing position. In addition, the RMSSD decreased from 20.8 to 4.2 ms, the HRpeak decreased by 13 bpm, and the tHRpeak increased by 18 s in the standing position significantly. There were no significant changes in the pre-viral infection RMSSD values in the supine position. The viral infection led to a significant change in HR and HRV parameters. The cardiac autonomic system reacted more sensitively in the standing position compared to the supine position after a viral infection in the present case study.

Conclusion: These data have provided supportive rationale as to why the OT with a change from supine to standing body position and the detection of different indicators based on HR and a vagal driven time-domain HRV parameter (RMSSD) is likely to be useful to detect viral diseases early on when implemented in daily routine. Given the case study nature of the findings, future research has to be conducted to investigate whether the use of the OT might be able to offer an innovative, non-invasive, and time-efficient possibility to detect and evaluate the health status of (elite endurance) athletes.

SARS-CoV2 infection: functional and morphological cardiopulmonary changes in elite handball players

There is increasing evidence of cardiac involvement post-SARS-CoV-2 infections in symptomatic as well as in oligo- and asymptomatic athletes. This study aimed to characterize the possible early effects of SARS-CoV-2 infections on myocardial morphology and cardiopulmonary function in athletes. Eight male elite handball players (27 ± 3.5 y) with past SARS-CoV-2 infection were compared with four uninfected teammates (22 ± 2.6 y). Infected athletes were examined 19 ± 7 days after the first positive PCR test. Echocardiographic assessment of the global longitudinal strain under resting conditions was not significantly changed (- 17.7% vs. - 18.1%). However, magnetic resonance imaging showed minor signs of acute inflammation/oedema in all infected athletes (T2-mapping: + 4.1 ms, p = 0.034) without reaching the Lake-Louis criteria. Spiroergometric analysis showed a significant reduction in VO2max (- 292 ml/min, - 7.0%), oxygen pulse (- 2.4 ml/beat, - 10.4%), and respiratory minute volume (VE) (- 18.9 l/min, - 13.8%) in athletes with a history of SARS-CoV2 infection (p < 0.05, respectively). The parameters were unchanged in the uninfected teammates. SARS-CoV2 infection caused impairment of cardiopulmonary performance during physical effort in elite athletes. It seems reasonable to screen athletes after SARS-CoV2 infection with spiroergometry to identify performance limitations and to guide the return to competition.

Safety and Impact on Training of the Influenza Vaccines in Elite Athletes Participating in the Rio 2016 Olympics

OBJECTIVE

The aim of the study was to evaluate the safety and tolerance of influenza vaccines for the northern and southern hemispheres in Polish elite athletes participating in the Rio 2016 Olympics.

DESIGN

Prospective, observational, cohort study.

SETTING

Institutional level.

PARTICIPANTS

Ninety-seven athletes vaccinated only with the northern hemisphere vaccine; 98 athletes received the southern hemisphere vaccine alone, whereas 39 athletes were vaccinated with both vaccines.

INTERVENTIONS

The athletes were vaccinated with a trivalent, inactivated influenza vaccine recommended for the northern hemisphere 2015/2016 and then with the vaccine recommended for the southern hemisphere 2016. Athletes kept a diary of adverse events and effects (if any) on training for 6 days after vaccination.

MAIN OUTCOME MEASURES

The percentage of general and local adverse events, number of lost or modified training sessions.

RESULTS

Significantly more local adverse events (pain and redness) were found in the group immunized with the vaccine for the northern hemisphere. There were no differences in the frequency of general adverse events and influence on training between groups. Of total 273 athletes who had 1911 training days during 6 days after vaccination, 6 athletes (2.2%) lost 13 training days (0.7%) and 16 athletes (5.9%) had to modify 34 (1.7%) training days within first 2 days after vaccination.

CONCLUSIONS

Athletes tolerated influenza immunization well. If they are going to travel to the other hemisphere during the influenza season, the use of the second influenza vaccine should be advised. Athletes should anticipate modification of trainings for 2 days after vaccination.

The Impact of Physical Activity on Pericarditis

Purpose of Review

To discuss the possible harmful effects and pathophysiology of exercise in cases of pericarditis, explore the role of multi-modality imaging to help guide exercise recommendations, and compare U.S. with European guideline recommendations on the safe resumption of physical activity following resolution of pericarditis.

Recent Findings

Despite multiple postulated mechanisms by which exercise may be harmful during active inflammation of the myocardium or pericardium, the exact pathophysiology remains largely unknown. The inclusion of multi-modality cardiac imaging may play a role in further elucidating the relationship of exercise with outcomes in pericarditis. More recently, the prevalence of COVID-19 cardiac involvement in athletes prior to returning to play appears lower than previously reported; however, current recommendations are consistent with those for other etiologies of pericarditis.

Summary

Further research is certainly needed to better understand the relationship between physical activity and pericarditis, the pathophysiology, and the prognostic role of multimodality imaging.

The Biathlon Injury and Illness Surveillance (BIIS) project protocol: a prospective cohort study across two World Cup seasons

Introduction

Reliably and accurately establishing injury and illness epidemiology in biathletes will provide insight into seasonal changes, provide potential to better embed innovative prevention strategies and advance sports medicine through the provision of effective healthcare to biathletes. The main objective of the Biathlon Injury and Illness Study (BIIS) is to provide the first comprehensive epidemiological profile of injury and illness in biathlon athletes during two consecutive Biathlon World Cup seasons over 2-years.

Methods

The BIIS study methodology is established in line with the International Olympic Committee (IOC) injury and illness surveillance protocols using a biathlon-specific injury and illness report form. Team medical staff will provide weekly data using injury and illness definitions of any injury or illness that receives medical attention regardless of time loss. Injuries or illness must be diagnosed and reported by a qualified medical professional (eg, team physician, physiotherapist) to ensure accurate and reliable diagnoses. Descriptive statistics will be used to identify the type, body region and nature of the injury or illness and athlete demographics such as age and gender. Summary measures of injury and illnesses per 1000 athlete-days will be calculated whereby the total number of athletes will be multiplied by the number of days in the season to calculate athlete-days.

Ethics and Dissemination

This study has been approved by the Bellbery Human Research Ethics Committee (HREC reference: 2017-10-757). Results will be published irrespective of negative or positive outcomes and disseminated through different platforms to reach a wide range of stakeholders.

The Relevance of a Physical Active Lifestyle and Physical Fitness on Immune Defense: Mitigating Disease Burden, With Focus on COVID-19 Consequences

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a fast spreading virus leading to the development of Coronavirus Disease-2019 (COVID-19). Severe and critical cases are characterized by damage to the respiratory system, endothelial inflammation, and multiple organ failure triggered by an excessive production of proinflammatory cytokines, culminating in the high number of deaths all over the world. Sedentarism induces worse, continuous, and progressive consequences to health. On the other hand, physical activity provides benefits to health and improves low-grade systemic inflammation. The aim of this review is to elucidate the effects of physical activity in physical fitness, immune defense, and its contribution to mitigate the severe inflammatory response mediated by SARS-CoV-2. Physical exercise is an effective therapeutic strategy to mitigate the consequences of SARS-CoV-2 infection. In this sense, studies have shown that acute physical exercise induces the production of myokines that are secreted in tissues and into the bloodstream, supporting its systemic modulatory effect. Therefore, maintaining physical activity influence balance the immune system and increases immune vigilance, and also might promote potent effects against the consequences of infectious diseases and chronic diseases associated with the development of severe forms of COVID-19. Protocols to maintain exercise practice are suggested and have been strongly established, such as home-based exercise (HBE) and outdoor-based exercise (OBE). In this regard, HBE might help to reduce levels of physical inactivity, bed rest, and sitting time, impacting on adherence to physical activity, promoting all the benefits related to exercise, and attracting patients in different stages of treatment for COVID-19. In parallel, OBE must improve health, but also prevent and mitigate COVID-19 severe outcomes in all populations. In conclusion, HBE or OBE models can be a potent strategy to mitigate the progress of infection, and a coadjutant therapy for COVID-19 at all ages and different chronic conditions.

Prediction of Upper Respiratory Illness Using Salivary Immunoglobulin A in Youth Athletes

PURPOSE

To evaluate the relative importance and predictive ability of salivary immunoglobulin A (s-IgA) measures with regards to upper respiratory illness (URI) in youth athletes.

METHODS

Over a 38-week period, 22 youth athletes (age = 16.8 [0.5] y) provided daily symptoms of URI and 15 fortnightly passive drool saliva samples, from which s-IgA concentration and secretion rate were measured. Kernel-smoothed bootstrapping generated a balanced data set with simulated data points. The random forest algorithm was used to evaluate the relative importance (RI) and predictive ability of s-IgA concentration and secretion rate with regards to URI symptoms present on the day of saliva sampling (URIday), within 2 weeks of sampling (URI2wk), and within 4 weeks of sampling (URI4wk).

RESULTS

The percentage deviation from average healthy s-IgA concentration was the most important feature for URIday (median RI 1.74, interquartile range 1.41-2.07). The average healthy s-IgA secretion rate was the most important feature for URI4wk (median RI 0.94, interquartile range 0.79-1.13). No feature was clearly more important than any other when URI symptoms were identified within 2 weeks of sampling. The values for median area under the curve were 0.68, 0.63, and 0.65 for URIday, URI2wk, and URI4wk, respectively.

CONCLUSIONS

The RI values suggest that the percentage deviation from average healthy s-IgA concentration may be used to evaluate the short-term risk of URI, while the average healthy s-IgA secretion rate may be used to evaluate the long-term risk. However, the results show that neither s-IgA concentration nor secretion rate can be used to accurately predict URI onset within a 4-week window in youth athletes.

Attitudes of elite athletes and their support staff to the influenza vaccine

BACKGROUND

Influenza is an important public health issue, even amongst healthy adults. Uptake rates of the influenza vaccine amongst elite athletes vary and can depend on the attitudes of their coaches, fellow athletes and support staff. International studies have documented a fear amongst elite athletes to the potential side effects of the vaccine.

AIMS

Determine the influenza vaccine uptake rates in elite Irish athletes and their support staff along with attitudes, fears and barriers to receiving it.

METHODS

A cross-sectional survey was performed in the Sport Ireland Institute. Elite athletes and support staff from the 2019 database were invited to participate via an anonymous online survey. The database included a variety of sports, e.g. athletics, boxing, cycling, rowing, swimming and para-athletics.

RESULTS

From 218 athletes and staff invited, 39% (n = 87 [43 male, 44 female]) responded to the online survey. Fifty-nine percent (n = 51) of participants received the influenza vaccine during the 2018/2019 season. Forty-six percent (n = 40) completely agree that the influenza vaccine is safe. Fourteen percent (n = 12) of participants believe the vaccine causes influenza. "Getting sick" from the vaccine was the biggest fear for participants. Athletes were least likely to recommend the influenza vaccine to others and most likely to fear missing time from training or work as a result of it.

CONCLUSIONS

Elite Irish athletes are vulnerable to contracting influenza annually, despite free access to immunisation. Barriers to receiving the vaccine include location access, education and fear of side effects.

Medical recommendations for home-confined footballers' training during the COVID-19 pandemic: from evidence to practical application

In early 2020, the world is facing a global emergency called COVID-19. Many professional footballers around the world are home confined. The maintenance of physical capacity is a fundamental requirement for the athlete, so the training sessions must be adapted to this unique situation. Specific recommendations must be followed concerning the type of training, its intensity, the precautions that have to be followed to avoid the possibility of contagion, and the restrictions in accordance with the presence of any symptoms. This article analyses the available scientific evidence in order to recommend a practical approach.

Biathlon Injury and Illness Surveillance project (BIIS): development of biathlon-specific surveillance forms in English, Russian, French and German

Objective

The aim of this project was to adapt the English, French, German and Russian versions of the International Olympic Committee (IOC) injury and illness surveillance form to be sport-specific for use in biathlon.

Methods

23 medical representatives from 16 of the 55 biathlon federations participated in this project to adapt the form and create disease coding relevant to biathlon. The English version of the IOC injury and illness surveillance form was used as the primary template. Four review rounds were used to develop electronic fillable PDF forms. The changes were then forward translated onto the Russian, French and German forms.

Results

Changes were made to event type to biathlon-specific events. A weekly reporting format was adopted in line with the race week format of World Cup events. Wherever possible, coding replaced free-text format to avoid translation issues. New codes were created to describe the time of injury/illness. A new symptom code was added to reflect the prevalence of respiratory infection: sore throat/cold symptoms. As the number of athletes in a team differs between weeks in the season, an additional question was added to ask for the ‘number of athletes in the team for the week’ and for the season.

Conclusion

This project provides a biathlon-specific injury and illness surveillance form in English, French, German and Russian. This forms the basis for surveillance that will contribute to a greater understanding of the illness and injury rate in elite biathletes and ultimately to enhanced athlete well-being and success in biathlon, and winter sports more generally.

Characterizing the molecular epidemiology of Staphylococcus aureus across and within fitness facility types

BACKGROUND

Staphylococcus aureus is a common bacterium found in the nose and throat of healthy individuals, and presents risk factors for infection and death. We investigated environmental contamination of fitness facilities with S. aureus in order to determine molecular types and antibiotic susceptibility profiles of contaminates that may be transmitted to facility patrons.

METHODS

Environmental swabs (n = 288) were obtained from several fitness facilities (n = 16) across Northeast Ohio including cross-fit type facilities (n = 4), traditional iron gyms (n = 4), community center-based facilities (n = 5), and hospital-associated facilities (n = 3). Samples were taken from 18 different surfaces at each facility and were processed within 24 h using typical bacteriological methods. Positive isolates were subjected to antibiotic susceptibility testing and molecular characterization (PVL and mecA PCR, and spa typing).

RESULTS

The overall prevalence of S. aureus on environmental surfaces in the fitness facilities was 38.2% (110/288). The most commonly colonized surfaces were the weight ball (62.5%), cable driven curl bar, and CrossFit box (62.5%), as well as the weight plates (56.3%) and treadmill handle (50%). Interestingly, the bathroom levers and door handles were the least contaminated surfaces in both male and female restroom facilities (18.8%). Community gyms (40.0%) had the highest contamination prevalence among sampled surfaces with CrossFit (38.9%), traditional gyms (38.9%), and hospital associated (33.3%) contaminated less frequently, though the differences were not significant (p = 0.875). The top spa types found overall were t008 (12.7%), t267 (10.0%), t160, t282, t338 (all at 5.5%), t012 and t442 (4.5%), and t002 (3.6%). t008 and t002 was found in all fitness facility types accept Crossfit, with t267 (25%), t548, t377, t189 (all 10.7%) the top spa types found within crossfit. All samples were resistant to benzylpenicillin, with community centers having significantly more strains resistant to oxacillin (52.8%), erythromycin (47%), clindamycin (36%), and ciprofloxacin (19%). Overall, 36.3% of isolates were multidrug resistant.

CONCLUSIONS

Our pilot study indicates that all facility types were contaminated by S. aureus and MRSA, and that additional studies are needed to characterize the microbiome structure of surfaces at different fitness facility types and the patrons at these facilities.

Muscle wasting in the presence of disease, why is it so variable?

Skeletal muscle wasting is a common clinical feature of many chronic diseases and also occurs in response to single acute events. The accompanying loss of strength can lead to significant disability, increased care needs and have profound negative effects on quality of life. As muscle is the most abundant source of amino acids in the body, it appears to function as a buffer for fuel and substrates that can be used to repair damage elsewhere and to feed the immune system. In essence, the fundamentals of muscle wasting are simple: less muscle is made than is broken down. However, although well-described mechanisms modulate muscle protein turnover, significant individual differences in the amount of muscle lost in the presence of a given severity of disease complicate the understanding of underlying mechanisms and suggest that individuals have different sensitivities to signals for muscle loss. Furthermore, the rate at which muscle protein is turned over under normal conditions means that clinically significant muscle loss can occur with changes in the rate of protein synthesis and/or breakdown that are too small to be measurable. Consequently, the changes in expression of factors regulating muscle turnover required to cause a decline in muscle mass are small and, except in cases of rapid wasting, there is no consistent pattern of change in the expression of factors that regulate muscle mass. MicroRNAs are fine tuners of cell phenotype and are therefore ideally suited to cause the subtle changes in proteome required to tilt the balance between synthesis and degradation in a way that causes clinically significant wasting. Herein we present a model in which muscle loss as a consequence of disease in non-muscle tissue is modulated by a set of microRNAs, the muscle expression of which is associated with severity of disease in the non-muscle tissue. These microRNAs alter fundamental biological processes including the synthesis of ribosomes and mitochondria leading to reduced protein synthesis and increased protein breakdown, thereby freeing amino acids from the muscle. We argue that the variability in muscle loss observed in the human population arises from at least two sources. The first is from pre-existing or disease-induced variation in the expression of microRNAs controlling the sensitivity of muscle to the atrophic signal and the second is from the expression of microRNAs from imprinted loci (i.e. only expressed from the maternally or paternally inherited allele) and may control the rate of myonuclear recruitment. In the absence of disease, these factors do not correlate with muscle mass, since there is no challenge to the established balance. However, in the presence of such a challenge, these microRNAs determine the rate of decline for a given disease severity. Together these mechanisms provide novel insight into the loss of muscle mass and its variation in the human population. The involvement of imprinted loci also suggests that genes that regulate early development also contribute to the ability of individuals to resist muscle loss in response to disease.

A systematic review exploring the relationship between infection and sudden unexpected death between 2000 and 2016: A forensic perspective

Death due to infectious diseases is a major health concern worldwide. This is of particular concern in developing countries where poor-socio economic status and a lack of healthcare resources contribute to the high burden of disease. In some cases death due to infection can be acute and aggressive, and death may occur without a diagnosis whilst the person is still alive. These deaths may ultimately lead to a medico-legal autopsy being performed. There are various mechanisms by which sudden death due to infection may occur. In addition, there are many risk factors associated with sudden death due to infection, which differ between infants and older individuals. However, it is unclear which pathogens and risk factors are most frequently associated with sudden death due to infection. Therefore a systematic review of articles and case reports published between 1 January 2000 and 30 June 2016 was undertaken in order to (1) explore the relationship between pathogens and their causative role and (2) identify the relationship between predisposing and/or risk factors associated with sudden death due to infection. Major databases were searched and after critical appraisal 143 articles were identified. It was found that respiratory infections and deaths involving bacterial pathogens were most commonly associated with these deaths. In addition the most common risk factors in infants were exposure to tobacco smoke and co-sleeping. In adults the most common risk factors were co-morbid conditions and illnesses. This information aids in a better understanding of these deaths and highlights the need for more research in this field, particularly in developing countries.

Effects of glycosylated hemoglobin levels on neutrophilic phagocytic functions

It is well established that diabetic patients with poor glycemic control have increased susceptibility to infections, but glucose levels have not been directly associated with this increase. The assessment of the effects of glycosylated hemoglobin (A₁ c) on the body’s ability to fight infections may be useful directly in establishing a link between elevated blood sugar and the risk of infections. A total of 127 subjects in Heart Pilot Study (HPS), sub-study of the Adventist Health Study 2 (AHS-2) completed a lifestyle, medical and food frequency questionnaire (FFQ) at baseline between 2013 and 2014. The A₁ c and phagocytic index (PI) were measured in the same blood sample and their associations were assessed using linear regression. Mean blood glucose (MBG) was estimated based on A₁ c levels using a standard formula. Three levels of MBG were used to compare prediabetic and diabetic ranges to the normal range. The PI is the average number of bacteria in the cytoplasm of 50 neutrophils, manually counted under a light microscope after the whole blood was briefly exposed to a standard dose of bacteria and stained. In multivariable analysis, we found that MBG in the prediabetic (117 to137 mg/dL) and diabetic (>137 mg/dL) ranges were associated with 12.9% (β= −0.129, 95% Cl: −0.30, 0.05) and 20.4% decrease in PI (β= −0.204, 95% Cl: −0.592, 0.184) compared to that, observed among those with normal MBG (p for trend=0.119). Elevated MBG levels contribute a decrease in the PI among those in the prediabetic and diabetic range compared to the normal range. Although our findings were not quite statistically significant due to low power which are clinically relevant in line with observations of an increased infections among diabetics. Further research on larger populations is needed.

How much is too much? (Part 2) International Olympic Committee consensus statement on load in sport and risk of illness

The modern-day athlete participating in elite sports is exposed to high training loads and increasingly saturated competition calendar. Emerging evidence indicates that inappropriate load management is a significant risk factor for acute illness and the overtraining syndrome. The IOC convened an expert group to review the scientific evidence for the relationship of load—including rapid changes in training and competition load, competition calendar congestion, psychological load and travel—and health outcomes in sport. This paper summarises the results linking load to risk of illness and overtraining in athletes, and provides athletes, coaches and support staff with practical guidelines for appropriate load management to reduce the risk of illness and overtraining in sport. These include guidelines for prescription of training and competition load, as well as for monitoring of training, competition and psychological load, athlete well-being and illness. In the process, urgent research priorities were identified.

[102 patients with suspected myocarditis : Clinical presentation, diagnostics, therapy and prognosis]

INTRODUCTION

Myocarditis is a disease which is difficult to diagnose and which includes a risk of the development of dilated cardiomyopathy and sudden cardiac death.

METHODS AND PATIENTS

In this study 102 patients were included from the time period 2003-2013 after diagnosis or suspected diagnosis of myocarditis in the department of internal medicine at the University Hospital Halle (Saale).

RESULTS

Of the study participants 77.5% were male and the average age was 35.5 ± 14.1 years. The symptoms reported by the patients were angina in 46.1%, dyspnea in 38.2%, performance deterioration in 29.4%, palpitations in 9.8% and syncope in 8.8%. In 45.1% of patients, symptoms were preceded by a respiratory infection. All patients underwent an echocardiogram and in 36.5% it was possible to demonstrate a regional wall motion abnormality and in 20.4% a pericardial effusion. A myocardial biopsy was performed in 15.6% of the patients. The presence of cardiotropic viruses was investigated in 37.3% of patients but was detected in only 5.9%. Cardiac magnetic resonance imaging (MRI) was performed in 82 patients of whom 33.3% showed a late enhancement and 11.9% a wall movement disorder. In this study four patients, all male, died and three suffered recurrent myocarditis.

CONCLUSION

This study showed the wide range of symptoms in myocarditis. Myocarditis is rarely severely manifested and in this study the mortality was 3.9%. For further optimization of the diagnostic and treatment algorithms, prospective, randomized studies would be desirable.

Mucosal immunity and upper respiratory tract symptoms in recreational endurance runners

The present study investigated the effects of a 12-week endurance-training intervention on salivary proteins and upper respiratory tract symptoms (URS) in 25 young men. Saliva samples of 25 recreational male endurance runners (age 34.6 years, body mass index = 23.8 kg·m(-2), peak aerobic capacity = 47.2 mL·kg(-1)·min(-1)) were collected before (PRE) and after (POST) the training intervention, in a fasting state, as well as both before and after a maximal incremental treadmill run. The training consisted of both continuous and interval training sessions, 4-6 times per week based on the polarized training approach. Participants filled in Wisconsin Upper Respiratory Symptom Survey-21 and were retrospectively divided into 2 groups according to whether they reported URS (URS group, n = 13) or not (HEALTHY group, n = 12). Basal salivary immunoglobulin A (sa-sIgA) levels were significantly higher (+70%, p < 0.05) in the HEALTHY group both at PRE and POST whereas no significant differences were observed in salivary immunoglobulin M, salivary immunoglobulin G, lysozyme, or salivary α-amylase activity (sAA). Sa-sIgA concentration at PRE significantly correlated with the number of sick-days (R = -0.755, p < 0.001) in all subjects. The incremental treadmill run acutely increased sAA significantly (p < 0.05) at PRE (200%) and POST (166%) in the HEALTHY group but not in the URS group. This study demonstrated that subjects, who experienced URS during the 12 weeks of progressive endurance training intervention, had significantly lower basal sa-sIgA levels both before and after the experimental endurance training period. In addition to sa-sIgA, acute sAA response to exercise might be a possible determinant of susceptibility to URS in endurance runners.

JAK/STAT signaling in Drosophila muscles controls the cellular immune response against parasitoid infection

The role of JAK/STAT signaling in the cellular immune response of Drosophila is not well understood. Here, we show that parasitoid wasp infection activates JAK/STAT signaling in somatic muscles of the Drosophila larva, triggered by secretion of the cytokines Upd2 and Upd3 from circulating hemocytes. Deletion of upd2 or upd3, but not the related os (upd1) gene, reduced the cellular immune response, and suppression of the JAK/STAT pathway in muscle cells reduced the encapsulation of wasp eggs and the number of circulating lamellocyte effector cells. These results suggest that JAK/STAT signaling in muscles participates in a systemic immune defense against wasp infection.

The impact of triathlon training and racing on athletes' general health

Although the sport of triathlon provides an opportunity to research the effect of multi-disciplinary exercise on health across the lifespan, much remains to be done. The literature has failed to consistently or adequately report subject age group, sex, ability level, and/or event-distance specialization. The demands of training and racing are relatively unquantified. Multiple definitions and reporting methods for injury and illness have been implemented. In general, risk factors for maladaptation have not been well-described. The data thus far collected indicate that the sport of triathlon is relatively safe for the well-prepared, well-supplied athlete. Most injuries 'causing cessation or reduction of training or seeking of medical aid' are not serious. However, as the extent to which they recur may be high and is undocumented, injury outcome is unclear. The sudden death rate for competition is 1.5 (0.9-2.5) [mostly swim-related] occurrences for every 100,000 participations. The sudden death rate is unknown for training, although stroke risk may be increased, in the long-term, in genetically susceptible athletes. During heavy training and up to 5 days post-competition, host protection against pathogens may also be compromised. The incidence of illness seems low, but its outcome is unclear. More prospective investigation of the immunological, oxidative stress-related and cardiovascular effects of triathlon training and competition is warranted. Training diaries may prove to be a promising method of monitoring negative adaptation and its potential risk factors. More longitudinal, medical-tent-based studies of the aetiology and treatment demands of race-related injury and illness are needed.

Physical inactivity and long-term rates of community-acquired sepsis

OBJECTIVE

The authors sought to determine the association between physical inactivity (characterized by exercise and television watching levels) and long-term rates of community-acquired sepsis.

METHODS

The study utilized a population-based cohort of 30,183 adult (≥45 years) community dwelling adults. Subjects reported weekly exercise (low=none, medium=1-3times/week, high=≥4times/week) and daily television watching (low=<1h/day, medium=1-3h/day, high=≥4h/day) levels. The authors evaluated the association between exercise, television watching and rates of sepsis, defined as hospital treatment for a serious infection with ≥2 Systemic Inflammatory Response Syndrome (SIRS) criteria.

RESULTS

Among 30,183 participants, 1500 experienced a sepsis event. Reported weekly exercise was: high 8798 (29.2%), medium 10,695 (35.4%), and low 10,240 (33.9%). Where available, reported daily television watching was: low 4615 (19.6%), medium 11,587 (49.3%) and high 7317 (31.1%). Decreased weekly exercise was associated with increased adjusted sepsis rates (high - referent; medium - HR 1.02, 95% CI 0.96-1.20; low - 1.33, 1.13-1.56). Daily television watching was not associated with sepsis rates. Sepsis rates were highest among those with both low exercise and high television watching levels (HR 1.49, 95% CI: 1.10-2.01).

CONCLUSIONS

Physical inactivity may be associated with increased long-term rates of community-acquired sepsis.

Febrile illness in the athlete

CONTEXT

Acute febrile illnesses are common in athletes over the course of training and competition seasons. Complete recovery and rapid yet safe return to participation are critical for competitive athletes. Alterations in thermoregulation, metabolism, fluid homeostasis, muscle strength, and endurance, as well as potential complications for the athlete and others, must be considered.

EVIDENCE ACQUISITION

The PubMed database was searched (1970-2013) for all English-language articles related to febrile illness in sport, using the keywords fever, febrile, body temperature, thermoregulation, infection, illness, disease, exercise, athlete, sport, performance, return to play, metabolism, hydration, and dehydration.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 4.

RESULTS

Limited data confirm that febrile illness is correlated with alterations in the body's thermoregulatory system, with increases in metabolic rate, and with effects in fluid homeostasis. Human and animal studies demonstrate a decrease in muscle strength and endurance secondary to muscle catabolism in febrile illness. However, indirect evidence suggests that regular exercise enhances the immune response. No strong clinical research has been published on return to play during or following acute febrile illness, excluding mononucleosis and myocarditis.

CONCLUSION

Fever is correlated with an increase in insensible fluid losses, dehydration, metabolic demands, and dysregulation of body temperature. Fever can have detrimental effects on the musculoskeletal system, including decreasing strength and endurance, generalized muscle catabolism, and increase in perceived fatigue. Participating in strenuous exercise during febrile illness can worsen the illness and has demonstrated increased lethality in animal models. No consensus recommendations support return to activity before resolution of fever, and training should be resumed gradually once fever and dehydration have resolved.

Prevention, diagnosis, and treatment of the overtraining syndrome: joint consensus statement of the European College of Sport Science and the American College of Sports Medicine

Successful training not only must involve overload but also must avoid the combination of excessive overload plus inadequate recovery. Athletes can experience short-term performance decrement without severe psychological or lasting other negative symptoms. This functional overreaching will eventually lead to an improvement in performance after recovery. When athletes do not sufficiently respect the balance between training and recovery, nonfunctional overreaching (NFOR) can occur. The distinction between NFOR and overtraining syndrome (OTS) is very difficult and will depend on the clinical outcome and exclusion diagnosis. The athlete will often show the same clinical, hormonal, and other signs and symptoms. A keyword in the recognition of OTS might be "prolonged maladaptation" not only of the athlete but also of several biological, neurochemical, and hormonal regulation mechanisms. It is generally thought that symptoms of OTS, such as fatigue, performance decline, and mood disturbances, are more severe than those of NFOR. However, there is no scientific evidence to either confirm or refute this suggestion. One approach to understanding the etiology of OTS involves the exclusion of organic diseases or infections and factors such as dietary caloric restriction (negative energy balance) and insufficient carbohydrate and/or protein intake, iron deficiency, magnesium deficiency, allergies, and others together with identification of initiating events or triggers. In this article, we provide the recent status of possible markers for the detection of OTS. Currently, several markers (hormones, performance tests, psychological tests, and biochemical and immune markers) are used, but none of them meet all the criteria to make their use generally accepted.

A self-reported questionnaire for quantifying illness symptoms in elite athletes

Purpose

To develop and evaluate a questionnaire that quantifies the self-reported frequency, duration and severity of illness symptoms in highly-trained athletes. We examined whether runners had more symptoms than recreationally-active individuals, and whether runners more prone to illness were undertaking more strenuous training programs.

Methods

A daily illness questionnaire was administered for three months during the summer to quantify the type, frequency, duration, and severity of illness symptoms as well as the functional impact on the ability to undertake exercise performance. A total of 35 participants (12 highly-trained runners living in a community setting and 23 recreationally-active medical students) completed the questionnaire.

Results

Runners had a similar frequency of illness (2.1 ± 1.2 vs. 1.8 ± 2.3 episodes, mean ± SD, P = 0.58), but substantially longer duration (5.5 ± 9.9 vs 2.8 ± 3.1 days, P < 0.01) and illness load (7.7 ± 16.2 vs 4.5 ± 4.8 units, P = 0.001) than age- and sex-matched recreationally-active individuals respectively. Runners more prone to illness symptoms had marginally higher training loads.

Conclusions

The athlete illness questionnaire is useful for quantifying the pattern of self-reported symptoms of illness in field settings. Highly-trained runners experience longer episodes of illness with a greater impact on daily activity than recreationally-active individuals.

Elevated Epstein-Barr virus loads and lower antibody titers in competitive athletes

Epstein-Barr virus (EBV) is a persisting herpesvirus which is controlled by the adaptive immune response after primary infection and maintained in a latent state. However, reactivation or persistent replication is observed in situations where the immune response is compromised. Since intensive physical training has been reported to diminish immune function, increased EBV load may be a cause of reduced performance and decreased ability to sustain high training loads in competitive athletes. Samples drawn from 209 athletes during their regular follow-up appointments were tested. One hundred sixty-five individuals of similar age not active in competitive sports served as case-controls. EBV load was quantified in peripheral blood leucocytes (PBLs) by real-time PCR, and EBV antibodies were detected in plasma by ELISA and immunoblot analysis. EBV DNA was detectable in 25 of 209 athletes and in 26 of 165 controls. Of note, the EBV load per 10(5) PBLs was 6.44 +/- 1.75 in the case and 1.67 +/- 0.44 copies in the controls, yielding a high significant difference (P < 0.0001). However, EBV-specific IgG titers were significantly lower in athletes (150.4 +/- 10.73 U ml(-1) vs. 241.6 +/- 18.59 U ml(-1)). As monitored by immunoblotting, primary infections were detected with low prevalence, three in the case group and one in the control group. These findings demonstrate that EBV is present at higher levels in athletes, but the antibody response is lower in athletes than in the controls. J. Med. Virol. 82:446-451, 2010. (c) 2010 Wiley-Liss, Inc.

[Myocarditis and sudden cardiac death in athletes. Diagnosis, treatment, and prevention]

Myocarditis is the reason for sudden cardiac death in 5-22% of athletes < 35 years of age. Actually, parvovirus B19 and human herpes virus 6 are the most important pathogens. Clinical presentation of myocarditis is heterogeneous, with all courses between asymptomatic and fulminant reported. Especially in athletes it is important to take subtle discomforts seriously and initiate further evaluation. Electrocardiogram, laboratory parameters, serologic markers, and echocardiography are helpful in diagnosis of myocarditis, but are not specific. Magnetic resonance imaging (MRI) of the heart has become an important tool in the evaluation of patients with myocarditis and allows noninvasive appraisal of myocardial inflammation using late enhancement. However, MRI is not able to assess viral persistence. Therefore, endomyocardial biopsy (EMB) remains the gold standard in diagnosis of myocarditis. When considering EMB in these athletes one should not ignore spontaneous healing in 50% of patients with myocarditis. Contrariwise, specific therapy (e.g., immunosuppression, interferon, immunoglobulins) for myocarditis is only feasible after getting results of EMB. When myocarditis is verified, athletes have to withdraw from sport for at least 6 months. Before restarting physical activity, a detailed examination is necessary and most of the patients will undergo another EMB. For prevention of myocarditis and sudden cardiac death it is recommended to stop elite sport for 4 weeks after an unspecific infection. Whether moderate sport can be started earlier is unclear.

The effect of aerobic exercise on neutrophil functions

PURPOSE

Intense exercise bouts are associated with a reduction of immune function and increased susceptibility to infections. Neutrophils act as a first line of defense to eliminate infectious agents and are also involved in muscle tissue inflammatory response to exercise. Intensive exercise suppresses several neutrophil functions including chemotaxis. The study investigates the pathophysiological mechanisms of impaired chemotaxis after submaximal aerobic exercise.

METHODS

Twenty-three healthy physically active adult males were tested before and 24 h after 30 min of treadmill running at 75% VO2max. N-formyl-Met-Leu-Phe (fMLP)-stimulated neutrophil migration, polarization, adherence, expression of adhesion molecules (CD11b/CD18), and chemotactic receptor (C5aR) were assessed preexercise and postexercise.

RESULTS

Neutrophil chemotaxis and polarization were found to be impaired 24 h postexercise. Adherence was impaired 24 h postexercise as well, but the expression of the adhesion molecule CD11b/CD18 was not affected. Further, the availability of the C5aR was found to be unaffected 24 h postaerobic exercise.

CONCLUSIONS

The pathophysiological mechanism of the impaired chemotaxis is likely related to the impaired postexercise neutrophil adherence and polarization but not to changes in the chemotactic receptor availability.

Exercise Induced Alterations in Rat Monocyte Number, Morphology, and Function

The purpose of this study was to verify the histophysiological alterations in monocytes and macrophages induced by short periods of exercise. Male Wistar rats (age = 2 months, body weight = 200g) were divided into seven groups (N = 6 each): sedentary control (C), groups exercised (swimming) at low intensity for 5 (5L), 10 (10L), and 15 minutes (15L), and groups exercised at moderate intensity for 5 (5M), 10 (10M) or 15 minutes (15M). At moderate intensity the animals carried a load of 5% of body weight on their backs. Blood monocytes were evaluated for quantity and morphology, and peritoneal macrophages were analyzed for quantity and phagocytic activity. Data were analyzed using ANOVA and Tukey's post hoc test (p ≤ 0.05). Low intensity groups and 5M exhibited an increase in monocyte levels when compared with the control. There was an increase in monocyte cellular area for the 5L, 10L, 5M and 10M groups; monocyte nuclear area increased for the 10L, 5M and 10M groups in comparison with the control. There was an increase in peritoneal macrophages for the 15L, 10M, 15M and decrease for the 5M group. Macrophage phagocytic capacity increased for low intensity groups and for 10M group. The exercise performed for short periods modulated macrophage levels and function, and monocyte levels and morphology, in an intensity-dependent manner. The sum of acute responses observed in this study may exert a protective effect against sickness and may be used to improve health and lifespan.

Alterações Induzidas Pelo Exercício no Número, Função e Morfologia de Monócitos de Ratos

O propósito desse estudo foi verificar as alterações histofisiológicas em monócitos e macrófagos induzidas por curtos períodos de exercícios. Ratos Wistar (idade = 2 meses, peso corporal = 200g) foram divididos em sete grupos (n=6 cada): controle sedentário (C), grupos exercitados (natação) na intensidade leve por 5 (5L), 10 (10L) e 15 minutos (15L), e grupos exercitados em intensidade moderada por 5 (5M), 10 (10M) e 15 minutes (15M). Na intensidade moderada os animais carregaram uma carga de 5% do peso corporal dos mesmos em seus respectivos dorsos. Os monócitos sangüíneos foram avaliados quanto à quantidade e morfologia e os macrófagos peritoneais foram analisados quanto à quantidade e atividade fagocitária. Os dados foram analisados usando ANOVA e Tukey’s post hoc test (p ≤ 0,05). Os grupos de intensidade leve e 5M apresentaram aumento nos níveis dos monócitos quando comparados com o controle. Foi observado aumento na área celular dos monócitos para os grupos 5L, 10L, 5M e 10M; a área nuclear aumentou para os grupos 10L, 5M e 10M em comparação com o controle. Houve aumento nos macrófagos peritoneais para os grupos 15L, 10M, 15M e diminuição no grupo 5M. A capacidade fagocitária dos macrófagos aumentou nos grupos de intensidade leve e para o grupo 10M. O exercício realizado por curtos períodos modulou o número e função dos macrófagos, assim como o número e morfologia dos monócitos, sendo tais alterações dependentes da intensidade. A soma das respostas agudas observadas nesse estudo pode exercer um efeito protetor contra doenças, podendo ser utilizada para a melhora da saúde e qualidade de vida.

Sudden cardiac death in young athletes: time for a Nordic approach in screening?

In 2005, the European Society of Cardiology published recommendations for cardiovascular screening in athletes. Discussion on whether screening is beneficial is ongoing. Recently, the first prospective results on effectiveness of screening in preventing sudden deaths were published from Italy. The results were supportive of screening, but did not provide conclusive evidence. Our suggestion for a Nordic approach on this issue is a directed cardiovascular examination initially involving elite athletes, because this is feasible with respect to the Nordic health care systems and the organization and logistics of elite competitive sports, but also because of the negative aspects of screening large populations. This directed cardiovascular examination would include personal and family history, clinical examination, and electrocardiography (ECG). Further examinations should thereafter be carried out in athletes with suggestive findings in the initial evaluation. The directed cardiovascular examination should be voluntary. It should be conducted at least once, with information on alarming symptoms (syncope, chest pain or dizziness during exercise) and heredity (sudden cardiac death or hereditary heart disease in near relatives) stressed to the athlete as indications for necessary check-ups in the future. The examination would also provide the athlete with an ECG recording, which is valuable as a reference at a later time.

Myocarditis and dilated cardiomyopathy in athletes: diagnosis, management, and recommendations for sport activity

This article focuses on uncommon heart diseases associated with an increased risk for sudden death during exercise, namely, myocarditis and dilated cardiomyopathy.

The reduction of voluntary physical activity after poly I:C injection is independent of the effect of poly I:C-induced interferon-beta in mice

One characteristic of sickness behavior in mice is demonstrated by a reduction in voluntary wheel-running activity during infection. Among synthetic double-stranded (ds) RNAs, polyriboinosinic: polyribocytidylic acid (poly I:C) activates to produce interferon (IFN) -beta, which plays an important role in anti-viral activity and host-defense. However, how voluntary wheel-running activity is regulated during poly I:C infection is unknown. To determine whether poly I:C-induced IFN-beta production is responsible for reduced spontaneous physical activity, we measured poly I:C-induced changes in voluntary wheel-running activity in mice. In this experiment, the mice were injected with poly I:C (0-5 mg/kg i.v.) and/or anti-IFN-beta neutralizing antibody (1.5x10(5) U/kg i.v.). We also observed the direct effect of injection of recombinant IFN-beta (rIFN-beta: 5.0x10(4) and 2.5x10(5) U/kg) on wheel-running behavior. Poly I:C treatment dose-dependently reduced wheel-running activity, and induced an increase in plasma IFN-beta in mice. However the activity was not attenuated by the neutralizing antibody specific to IFN-beta treatment. Additionally, the wheel-running activity in rIFN-beta treated mice was maintained, although they showed a higher IFN-gamma inducible protein (IP)-10 concentration in plasma compared with that of the vehicle group. Our results suggest that the transient reduction in physical activity after poly I:C injection is induced dose dependently, but that the mediator might not be poly I:C-induced IFN-beta.

Mecanismos adaptativos do sistema imunológico em resposta ao treinamento físico

O treinamento físico, de intensidade moderada, melhora os sistemas de defesa, enquanto que o treinamento intenso causa imunossupressão. Os mecanismos subjacentes estão associados à comunicação entre os sistemas nervoso, endócrino e imunológico, sugerindo vias autonômicas e modulação da resposta imune. Células do sistema imune, quando expostas a pequenas cargas de estresse, desenvolvem mecanismo de tolerância. Em muitos tecidos tem-se demonstrado que a resposta a situações agressivas parece ser atenuada pelo treinamento físico aplicado previamente, isto é, o treinamento induz tolerância para situações agressivas/estressantes. Nesta revisão são relatados estudos sugerindo os mecanismos adaptativos do sistema imunológico em resposta ao treinamento físico.

Myocarditis: when to suspect and how to diagnose it in athletes

Myocarditis should be suspected in athletes with unexplained cardiac arrhythmias and dysfunction, especially if preceded by a flu-like syndrome. An early diagnosis is desirable in order to avoid the risk of fatal consequences, since physical activity can enhance the inflammatory process. Although several diagnostic tools can be useful for the diagnosis of myocarditis, endomyocardial biopsy is still the gold standard. Athletes with myocarditis should be withdrawn from all competitive sports for at least 6 months and resume training when ventricular function and cardiac dimensions return to normal and the clinically relevant arrhythmias disappear. In the presence of life-threatening arrhythmias or rapidly progressive cardiac dysfunction an antiviral or an immunosuppressive treatment should be considered depending on whether a viral agent is present or absent, respectively, in the myocardium.

Exercise immunology: the current state of man and mouse

The mechanisms governing the body's response to physical exercise have been investigated from various perspectives including metabolism, nutrition, age and sex. Increased attention to the immune system during recent decades is reflected by a rapidly growing number of publications in the field. This article highlights the most recent findings and only briefly summarises more basic concepts already reviewed by others. Topics include Th1/Th2 cytokine balance, inoculation time, age and immune compensation. Some less investigated areas are discussed including studies in children, the environment and dendritic cells. Because physical exercise enhances some aspects and suppresses other aspects of immunity, the biological significance of alterations in the immune system are unknown. So far, no link between immunological alterations and infection rate has been established and infection after strenuous physical exercise is equally likely to be the result of exercising with an already established rather than a new infection. If there is an increased risk for infections with increased exercise duration and intensity, why do overtrained athletes not display the greatest risk for upper respiratory tract infections? Increased knowledge on immune system modulations with physical exercise is relevant both from a public health and elite athlete's point of view.