IOC consensus statement on recommendations and regulations for sport events in the heat.

This document presents the recommendations developed by the IOC Medical and Scientific Commission and several international federations (IF) on the protection of athletes competing in the heat. It is based on a working group, meetings, field experience and a Delphi process. The first section presents recommendations for event organisers to monitor environmental conditions before and during an event; to provide sufficient ice, shading and cooling; and to work with the IF to remove regulatory and logistical limitations. The second section summarises recommendations that are directly associated with athletes' behaviours, which include the role and methods for heat acclimation; the management of hydration; and adaptation to the warm-up and clothing. The third section explains the specific medical management of exertional heat stroke (EHS) from the field of play triage to the prehospital management in a dedicated heat deck, complementing the usual medical services. The fourth section provides an example for developing an environmental heat risk analysis for sport competitions across all IFs. In summary, while EHS is one of the leading life-threatening conditions for athletes, it is preventable and treatable with the proper risk mitigation and medical response. The protection of athletes competing in the heat involves the close cooperation of the local organising committee, the national and international federations, the athletes and their entourages and the medical team.

Acute in-competition medical care at the Tokyo 2020 Olympics: a retrospective analysis.

OBJECTIVE: To analyse injuries and illnesses during the 2020 Tokyo Olympic Summer Games. METHODS: This retrospective descriptive study included 11 420 athletes from 206 National Olympic Committees and 312 883 non-athletes. Incidences of injuries and illnesses during the competition period from 21 July to 8 August 2021 were analysed. RESULTS: A total of 567 athletes (416 injuries, 51 non-heat-related illnesses and 100 heat-related illnesses) and 541 non-athletes (255 injuries, 161 non-heat-related illnesses and 125 heat-related illnesses) were treated at the competition venue clinic. Patient presentation and hospital transportation rates per 1000 athletes were 50 and 5.8, respectively. Marathons and race walking had the highest incidence of injury and illness overall (17.9%; n=66). The highest incidence of injury (per participant) was noted in boxing (13.8%; n=40), sport climbing (12.5%; n=5) and skateboarding (11.3%; n=9), excluding golf, with the highest incidence of minor injuries. Fewer infectious illnesses than previous Summer Olympics were reported among the participants. Of the 100 heat-related illnesses in athletes, 50 occurred in the marathon and race walking events. Only six individuals were transported to a hospital due to heat-related illness, and none required hospital admission. CONCLUSION: Injuries and heat-related illnesses were lower than expected at the 2020 Tokyo Olympic Summer Games. No catastrophic events occurred. Appropriate preparation including illness prevention protocols, and treatment and transport decisions at each venue by participating medical personnel may have contributed to these positive results.

The Tokyo 2020 Olympic and Paralympic pharmacy services during the COVID-19 pandemic.

BACKGROUND: During the Tokyo 2020 Games, pharmacists were required to provide appropriate pharmacotherapeutic care to athletes and officials at the polyclinic. Owing to the worldwide COVID-19 pandemic that was prevalent at the Games, it was imperative to strengthen infection control measures in the setting of such a major sporting event and to prevent and minimize the spread of COVID-19. OBJECTIVE: This study reports on the COVID-19 infection control measures and services provided by the pharmacy at the Tokyo 2020 Games. By evaluating pharmacy operations that took place under the COVID-19 protocol, this study provides insights for the organization of future sporting events, specifically their medical facilities. METHODS: Infection control measures in the pharmacy were implemented in accordance with the manual for dealing with COVID-19 infections. The number and content of issued and dispensed prescriptions were obtained from the electronic medical records and pharmacy department systems. These data were compared with those of the London 2012 Games, which were used as a reference for the pharmacy operations at the Tokyo 2020 Games. RESULTS: The participating pharmacists were fully trained in infection control measures. The number of prescriptions issued during the Olympics and Paralympics were 1120 and 1022, respectively. Prescriptions issued at the fever clinic accounted for 4% of the total number (77/2142). No influenza antiviral medications were prescribed, though medications to alleviate cold-like symptoms were issued. Compared to the London 2012 Games, there was a decrease (-59%) in the number of prescriptions. CONCLUSION: The positive impact of COVID-19 infection control measures was evident. The volume of prescriptions at the Tokyo 2020 Games was lower than that at the London 2012 Games. It was inferred that this was due to thorough infection control measures as well as enhanced pre-entry medical checkups before entering Japan, which reduced the incidence of diseases.

Gender bias in sports medicine: an international assessment of sports medicine physicians' perceptions of their interactions with athletes, coaches, athletic trainers and other physicians.

OBJECTIVES: To evaluate the difference between female and male sports medicine physicians regarding disrespectful attitudes and sexual harassment perceived from athletes, coaches, physicians, athletic trainers (ATs) and organisations/administrations. METHODS AND STUDY DESIGN: anonymous survey was distributed to sports medicine physicians practicing in 51 countries. χ2 analysis was used to detect differences between female and male sports medicine physicians and logistic regression analysis was used to determine the independent variables that affect disrespectful attitudes and sexual harassment from sports participants. RESULTS: 1193 sports medicine physicians (31.9% female) participated from 51 countries. The survey revealed that female physicians, compared with male physicians, perceive significantly more disrespect or have their judgement questioned more by the following categories: male and female athletes, male and female coaches, female physicians with more years of experience, male physicians (regardless of years of experience), male and female ATs and organisation/administrations (all p<0.05). The only category where the frequency of disrespect was perceived equally by male and female physicians was during their interactions with female physicians who have the same or lesser years of experience. Female sports medicine physicians noted more sexual harassment than male physicians during interactions with male athletes, coaches, ATs and physicians (all p<0.001). In the logistic regression, gender was a related factor for perceiving disrespect, especially from male coaches (OR=2.01) and physicians with more years of experience (OR=2.18). CONCLUSIONS: Female sports medicine physicians around the world experience disrespectful attitudes, questioning of their judgement and are sexually harassed significantly more often than male counterparts.

Head Injury Assessment in the Elite Level Rugby Union in Japan: Review of 3 Seasons.

Head Injury Assessment (HIA) is the screening tool for head injury during a rugby game. The purpose of this study was to investigate the epidemiology of HIA in the Japan Rugby Top League (JRTL). The incidences of HIA, defined concussion (per 1,000 player-hours) and repeated concussions were evaluated in three seasons (2016-17, 2017-18, 2018-19; total 360 games). The HIA incidence rates were 12.7 (95% confidence interval 9.5-15.9), 20.8 (16.8-24.9), and 25.0 (20.5-29.5) in each season. HIA-1 criteria 2, which is applied for suspected concussion cases, was performed for 46 cases in the 2016-17 season, 81 cases in the 2017-18 season, and 88 cases in the 2018-19 season. The concussion incidence rates were significantly greater in the 2017-18 season (9.6/1000 player-hours, 95% confidence interval 6.8-12.4) and the 2018-19 season (14.4, 11-17.8) compared to the 2016-17 season (4.8, 2.8-6.8). The number of repeated concussion cases in the same season was 1 in the 2016-17 season and 4 in both the 2017-18 and 2018-19 seasons. This study confirmed significantly higher HIA and concussion incidence rates over time. Although the HIA system might have been established in the three seasons in JRTL, comprehensive management needs to be improved to prevent repeated concussions.

Bone parameters of elite athletes with oligomenorrhea and prevalence seeking medical attention: a cross-sectional study.

INTRODUCTION: Since the definition of secondary amenorrhea is cessation of regular menses for more than 3 months, it is likely that athletes with irregular menstrual cycles, including oligomenorrhea, do not consider the condition as serious. However, the consequences of untreated oligomenorrhea have not been investigated in elite track and field athletes. MATERIALS AND METHODS: The cohort consisted of 91 elite-level track and field athletes. Body compositions, including bone parameters and bone turnover markers (BTMs), were measured. RESULTS: Among the 91 participants, 52 were eumenorrheic and 33 were oligomenorrheic. The eumenorrheic athletes had significantly higher bone mineral density (BMD) and bone mineral content (BMC) of the lumbar spine, lower extremities, and whole body than had the oligomenorrheic athletes (p < 0.01). There were no significant differences in BTMs between the two groups, but oligomenorrheic athletes had significantly lower percent body fat. CONCLUSION: More than 40% of the elite-level female track and field athletes in this study reported menstrual disorders with oligomenorrhea as the most common. However, none sought medical attention. As compared to the eumenorrheic athletes, the oligomenorrheic athletes had lower BMC and BMD. Hence, if an athlete is oligomenorrheic, bone parameter measurements are considerably important.

Prehospital management of exertional heat stroke at sports competitions: International Olympic Committee Adverse Weather Impact Expert Working Group for the Olympic Games Tokyo 2020.

OBJECTIVES: This document aimed to summarise the key components of exertional heat stroke (EHS) prehospital management. METHODS: Members of the International Olympic Committee Adverse Weather Impact Expert Working Group for the Olympic Games Tokyo 2020 summarised the current best practice regarding the EHS prehospital management. RESULTS: Sports competitions that are scheduled under high environmental heat stress or those that include events with high metabolic demands should implement and adopt policy and procedures for EHS prehospital management. The basic principles of EHS prehospital care are: early recognition, early diagnosis, rapid, on-site cooling and advanced clinical care. In order to achieve these principles, medical organisers must establish an area called the heat deck within or adjacent to the main medical tent that is optimised for EHS diagnosis, treatment and monitoring. Once admitted to the heat deck, the rectal temperature of the athlete with suspected EHS is assessed to confirm an elevated core body temperature. After EHS is diagnosed, the athlete must be cooled on-site until the rectal temperature is below 39°C. While cooling the athlete, medical providers are recommended to conduct a blood analysis to rule out exercise-associated hyponatraemia or hypoglycaemia, provided that this can be safely performed without interrupting cooling. The athlete is transported to advanced care for a full medical evaluation only after the treatment has been provided on-site. CONCLUSIONS: A coordination of care among all medical stakeholders at the sports venue, during transport, and at the hospital is warranted to ensure effective management is provided to the EHS athlete.

Bone Metabolism, Bone Mineral Content, and Density in Elite Late Teen Female Sprinters.

With intensive training, bone injuries are a major concern for athletes. To assess bone condition, we often measure bone turnover markers, bone mineral content and density; however, in junior athletes, it is not easy to distinguish changes caused by bone injuries from those caused by growth, because the metabolism is increased in both cases. Moreover, although some studies have examined female endurance athletes, knowledge regarding changes in static and dynamic bone conditions in late teen athletes is limited. In this study, we measured the bone mineral content and density, as well as bone turnover markers, in 40 elite female sprinters in their late teens. Whole body mode dual-energy X-ray absorptiometry was performed to measure bone mineral content and density. Blood samples were collected to determine bone resorption and formation markers at the end of track season in 2016 and during the same period of the following year. Body weight and bone mineral content significantly increased, and tartrate-resistant acid phosphatase type 5b, bone-type alkaline phosphatase, and osteocalcin significantly decreased after a year. Furthermore, the rate of change in bone mineral content was higher in younger athletes, indicating that bone growth approaches completion in the late teen years and that bone metabolism accordingly decreases.

Beneficial Effects of Yoga Stretching on Salivary Stress Hormones and Parasympathetic Nerve Activity.

This study aimed to determine the effect of yoga stretching on salivary stress hormones and cardiac autonomic nervous system. To our knowledge, this study is the first to investigate changes in cardiac autonomic nervous system after yoga stretching. In this crossover design study, 10 adult men (age, 26.3 ± 2.5 years) without yoga experience participated in the rest and yoga trials for 90 min. Measurements were carried out before (pre), immediately (post), 60 min, and 120 min after rest or yoga stretching. Saliva samples were collected by chewing a sterile cotton ball at a frequency of 60 cycles per minute. Salivary cortisol and testosterone concentrations were measured using an enzyme-linked immunosorbent assay. With the subjects in the sitting position, heart rate variability was measured using pulse analyzer plus for 150 seconds. As regards rate changes, salivary testosterone level tended to increase (p = 0.088), testosterone/cortisol ratio significantly increased (p < 0.05), and cortisol level significantly decreased (p < 0.05) at 120 min after yoga stretching. The square root of the mean-squared differences of successive normal-to-normal intervals and natural logarithm high-frequency component, which are indicators of parasympathetic nerve activity, increased at 60 min (p < 0.05) and 120 min (p < 0.05) in the yoga trial, respectively. In conclusion, yoga stretching can enhance parasympathetic nerve activity and improve stress hormones. Therefore, yoga stretching may be useful to compensate for physical inactivity and increase life expectancy in the general population.

Medical services at the 2017 Sapporo Asian winter games: injury and illness epidemiology at a 34-nation multisport event.

OBJECTIVES: We describe the medical services provided and report the injuries and illnesses that occurred at the eighth Asian Winter Games 2017. METHODS: A total of 2010 athletes and team officials from 32 National Olympic Committees and 2 guest countries attended this event; medical services were provided for 16 days. Medical data (medical care and physiotherapy) were collected for the same period by the organising committee for athletes and non-athletes (team officials, workforce, media and spectators) and recorded on the electronic medical record system at the medical rooms in the venues and the team residences. RESULTS: We recorded 745 medical encounters (medical care, 443; physiotherapy, 302), of which 549 (74%) were among athletes. There were 214 injuries as well as 144 illnesses and other medical conditions. Of the 1164 athletes, 549 (47%) utilised the services. Ice hockey, snowboarding and alpine skiing had high rate of medical encounters. More than half of the delegations were not accompanied by team doctor, and rate of medical encounters was high in these teams. The vast majority of patients transferred to hospital for further care were mostly athletes (n=36 out of 41), mostly alpine skiers and ice hockey players. CONCLUSION: Injuries and illnesses varied depending on NOC medical staffing and sport events. These data will serve organisers of medical and physiotherapy services in the Asian Winter Games and similar large events.

Yoga stretching for improving salivary immune function and mental stress in middle-aged and older adults.

Protection against age-related immune suppression is important in elderly individuals. This study determined the effect of yoga on mucosal immune function and mental stress. Saliva samples were collected from 23 adult women (age: 60.4 ± 10.4 years) before and after 90 minutes of yoga stretching or rest to measure secretory immunoglobulin A (SIgA), cortisol, and testosterone. The SIgA concentration and secretion rate were significantly higher after yoga than before (p < .05). The cortisol concentration and secretion rate were lower and testosterone secretion rate higher after yoga (p < .05). Yoga stretching can reduce stress and enhance mucosal immune function in elderly women.

Ageing and free-living daily physical activity effects on salivary beta-defensin 2 secretion.

This study examined ageing and free-living daily physical activity effects on salivary human beta-defensin 2 (hBD2). A total of 168 healthy elderly and 26 healthy young volunteers underwent saliva sampling. Free-living step count, energy expenditure and activity durations at specific intensity levels (inactive, light, moderate and vigorous) were evaluated. The results show significantly lower salivary hBD2 secretion rates for elderly than for young participants (P < 0.05). Data from elderly participants were stratified by steps per day using quartiles (Q1-Q4) for distribution. Elderly in quartiles respectively showed step counts of 3145 ± 129 in Q1, 5294 ± 83 in Q2, 7001 ± 86 in Q3 and 10,236 ± 416 steps · day-1 in Q4. In elderly participants, significant differences were found in the mean step count, energy expenditure and activity duration with increasing pedometer-determined activity quartiles. hBD2 secretion rates were significantly higher for Q2, Q3 and Q4 than for Q1 (P < 0.05). Elderly participants in Q3 had the highest hBD2 secretion. In conclusion, these results suggest that moderate physical activity in daily living improves age-related impairment of oral immune function mediated by hBD2. For oral immune function enhancement and for prevention of upper respiratory tract infections in elderly people, we recommend accumulation of more than 7000 steps · day-1.

Use of supplements by Japanese elite athletes for the 2012 Olympic Games in London.

OBJECTIVE: To investigate supplement use among Japanese elite athletes. DESIGN: We conducted a cross-sectional survey study using individual interviews during athletes' medical evaluations. SETTING: One to 5 months before the Olympic Games in 2012, London, United Kingdom. PARTICIPANTS: Five hundred fifty-two Japanese athletes for the London Games, including candidates. INDEPENDENT VARIABLES: Sex, sports, supplement category, and participation. MAIN OUTCOME MEASURES: Whether athletes used supplements, what products were used, the frequency and purposes of use, and from what sources athletes received information on supplements. RESULTS: All 552 athletes were interviewed by pharmacists regarding supplement use and agreed to the survey. Of them, 452 (81.9%) used 1 or more supplement products in the year before the study; a total of 952 different products (mean = 1.7, SD = 1.4) were used. The most commonly used supplement was amino acids (310 athletes; 56.2%), and 358 (38.7%) of the total products were amino acids. Of the athletes, 241 (43.7%) took at least 1 supplement daily, and of the supplements, 457 (49.4%) were taken daily. The most common purpose for supplement use was recovery from fatigue-327 (59.2%) athletes chose this answer, and 486 (52.5%) products were used for this purpose. Finally, regarding athletes' information sources on supplements, coaches, managers, and trainers were the most frequent advisors (275 athletes, 49.8%; 466 products, 50.4%). CONCLUSIONS: The results revealed widespread supplement use among Japanese elite athletes for the London Olympic Games. Education system was required not only for athletes but also for athletes' entourage, such as coaches, managers, trainers, and supplement companies. CLINICAL RELEVANCE: This study will provide basic data for establishing an education system that would better guide athletes' use of supplements.

The effects of Lactobacillus pentosus strain b240 and appropriate physical training on salivary secretory IgA levels in elderly adults with low physical fitness: a randomized, double-blind, placebo-controlled trial.

The purpose of the study was to evaluate the effects of Lactobacillus pentosus strain b240 (b240) intake and appropriate physical training on salivary secretory immunoglobulin A secretion in elderly adults with low physical fitness. Elderly adults with low physical fitness (daily step count below 3,500 steps) were divided into 2 groups: a b240 intake + exercise group (b240 group) and a placebo intake + exercise group (placebo group). Each subject continued intake of b240 or placebo and moderate-intensity resistance exercise for 12 weeks. Before and 4, 8, and 12 weeks after the start of intervention, each subject underwent saliva sampling. Before and after intervention, physical fitness tests and step count were measured. Our results showed that secretory immunoglobulin A secretion in 57 subjects during the b240/placebo intake period was significantly greater in the b240 group than in the placebo group (p<0.05). There were no significant changes in physical fitness tests before and after intervention in the 2 groups. The daily amount of walking increased significantly after intervention in both groups (p<0.05). These results suggest that in elderly adults with low physical activity and fitness, intake of b240 with appropriate physical exercise elevate salivary secretory immunoglobulin A secretion.

Navigating implementation barriers: a holistic approach to improving exertional heat stroke management.

Objectives: To assess the shift in medical volunteers' perception and practice surrounding exertional heat stroke (EHS) prehospital management after the Tokyo 2020 Olympic Games. Methods: An online survey was sent to medical volunteers assigned to work at high EHS risk events during the Tokyo 2020 Olympic Games. Surveys were sent at the time of initial training, immediately after the Games, and one year after the Games. The survey investigated medical volunteers' perceptions and practices regarding the assessment of rectal temperature and the use of whole-body cold water immersion (CWI) as prehospital management of EHS. In addition, an open-ended question was prepared to examine barriers and facilitators of their chosen perception and/or behaviour. Results: The lack of knowledge about rectal temperature assessment improved over time, but the actual implementation did not. Meanwhile, increased utilisation of CWI was observed 1 year after the Games. The lack of equipment, apprehension towards rectal temperature assessment, the perception of difficulty getting patient consent, concerns for hypothermic overshoot and the number of required medical providers were raised as barriers to implementation. Conclusion: Some improvements were observed in perception and practice; however, further organisational and financial support is warranted for a broader skill transfer and implementation.

International study of physicians' opinion on physician-patient sex concordance when treating athletes.

BACKGROUND: The effect of physician-patient sex concordance in medicine has been reported in many studies. Whether physicians believe that the sex concordance between physician and athlete influences treatment has not been investigated. OBJECTIVE: To determine whether physicians believe that the sex concordance between physician and athlete influences treatment. DESIGN: Cross-sectional study. SETTING: Online survey. PARTICIPANTS: One thousand one hundred ninety-three sports medicine physicians in 51 countries. Participants were sports medicine physicians trained in orthopedics (n = 443 [37.1%]) and nonorthopedics (n = 750 [62.9%]). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Participants were asked to decide whether sex of the physician made them better suited to care for athletes of concordant or different sexes along with their personal background. RESULTS: Orthopedic sports medicine physicians agreed less than nonorthopedic sports medicine physicians regarding the statement "MALE sports medicine physicians are better suited than their female counterparts to care for MALE athletes" (odds ratio [OR] 0.56, 95% confidence interval [CI] 0.35-0.91, p = .02), and compared to sports medicine physicians based in Europe, those based in Asia agreed more to this statement (OR 7.91, 95% CI 4.60-13.60, p < .01). In addition, regarding the statement "FEMALE sports medicine physicians are better suited than their male counterparts to care for FEMALE athletes," compared to sports medicine physicians based in Europe, those based in Asia (OR 9.12, 95% CI 5.63-14.79, p < .01) and North America (OR 2.18, 95% CI 1.46-3.25, p < .01) agreed more and orthopedic sports medicine physicians agreed less than nonorthopedic sports medicine physicians (OR 0.61, 95% CI 0.39-0.93, p = .02) to this statement. CONCLUSIONS: Sports medicine physicians trained in orthopedics felt sex concordance was less important than physicians trained in other specialties. Asian sports medicine physicians believed sex concordance was more important compared to physicians in other regions.

Injuries and illness of athletes at the Tokyo 2020 Olympic and Paralympic summer games visiting outside facilities.

This study aimed to identify the reasons for transferring athletes to local medical facilities during the Olympic and Paralympic Games. Data on 567 injuries and other illnesses of athletes treated at the on-site clinics were collected from the Tokyo 2020 Organizing Committee. Of these, 84 athletes who required outpatient care during the Games were registered for this survey. During the Olympic and Paralympic Games, 66 (8.3/1 000) and 18 (7.2/1 000) athletes, respectively, consulted external medical facilities. In the Olympic Games, the reasons for these visits included 48 cases (72.7%) of injuries, 13 (19.7%) cases of illnesses, and 5 (7.6%) cases of heat stroke illness (HSI). Of these patients, 56 (84.9%) were treated as outpatients and 10 (15.1%) were hospitalized, while three of these patients required hospitalization for > 7 days. On the other hand, in the Paralympics Games, there were 7 (38.8%) cases of injuries, 9 (50.0%) other illnesses, 1 (5.6%) case of HSI, and 1 (5.6%) other cases, of which 11 (61.1%) were treated as outpatients and 7 (38.9%) were hospitalized, but none was hospitalized for > 7 days. Injuries accounted for 70% of the total cases at the 2021 Olympic Games, but only three (0.05%) were severe cases that required hospitalization for more than 1 week. In contrast, in the Paralympic Games, other illnesses accounted for approximately half of the total cases. This study provides details on the extent of injuries and other illnesses that were transferred to outside facilities, which has not been documented in previous games.

Effects of yoga exercise on salivary beta-defensin 2.

PURPOSE: Yoga stretching can be done comfortably and easily by beginners and older adults to compensate for lack of exercise or poor health maintenance. The aim of this study was to determine the effect of yoga stretching on mucosal immune functions, primarily human ß-defensin 2 (HBD-2) in saliva. METHODS: Fifteen healthy adults (age, 60.4 ± 8.0 years) participated in the study. Participants rested for 90 min on the first day and performed yoga for 90 min on the second day. Measurements were carried out before and after rest or yoga. Saliva samples were collected by chewing a sterile cotton at a frequency of 60 cycles per min. Salivary HBD-2 concentration was measured using an enzyme-linked immunosorbent assay. RESULTS: HBD-2 concentration after yoga stretching (165.4 ± 127.1 pg/mL) was significantly higher than that before yoga stretching (84.1 ± 63.4 pg/mL; p < 0.01). HBD-2 expression rate after yoga stretching (232.8 ± 192.9 pg/min) was significantly higher than that before yoga stretching (110.7 ± 96.8 pg/min; p < 0.01). HBD-2 concentration (p < 0.05) and HBD-2 expression rate (p < 0.01) at post on the second day (yoga) was significantly higher than that on the first day (rest). POMS score of anger-hostility was lower after yoga than before. CONCLUSIONS: Yoga stretching for 90 min can increase salivary HBD-2 expression in older adults. Therefore, yoga stretching might be useful for older adults and athletes to maintain their health.

Altered secretory immunoglobulin A on skin surface after intensive exercise.

The aim of this study was to determine the effects of high-intensity endurance exercise on skin immunity by estimating secretory immunoglobulin A (SIgA) and staphylococci on skin surface. Seven healthy adult men (age, 22.3 ± 2.0 years) performed bicycle exercise at 75% HRmax for 60 minutes from 2030 to 2130 hours. Secretory immunoglobulin A was obtained from 1 ml extraction liquids stirred with the microtube homogenizer in the open end of a polypropylene tube for 60 seconds. Secretory immunoglobulin A concentrations were measured using enzyme-linked immunosorbent assay. Staphylococci were harvested by pressed agar-based media against skin surface. Skin surface samples were collected from the chest and the forearm on the first day at 2030 hours (before rest, A1), 2130 hours (after rest, A2), and 2230 hours (after showering, A3); the next morning at 0700 hours (A4); on the second day at 2030 hours (before exercise, B1), 2130 hours (after exercise, B2), and 2230 hours (after showering, B3); and the next morning at 0700 hours (B4). Secretory immunoglobulin A concentration on the forearm was significantly lower at B2 (p < 0.05) and B3 (p < 0.05) than that at B1 and that on the chest at B1 tended to be higher compared with B2 (p = 0.084) and B3 (p = 0.075). The number of staphylococci was significantly higher at B2 than that at B1 (p < 0.01) and B4 (p < 0.01) on the forearm. We conclude that high-intensity endurance exercise might depress immune function and enhance infectious risk on skin surface. Coaches should encourage their athletes to take a shower and change into clean clothes immediately after sports activities and athletes should maintain a clean skin surface to decrease the infectious risk on skin surface.

Effects of High-Intensity Endurance Exercise on Epidermal Barriers against Microbial Invasion.

For athletes, preventing infectious disease on skin is important. Examination measurement of epidermal barriers could provide valuable information on the risk of skin infections. The aim of this study was to determine the effects of high-intensity endurance exercise on epidermal barriers. Six healthy adult males (age; 22.3 ± 1.6 years) performed bicycle exercise at 75%HRmax for 60 min from 18:30 to 19:30. Skin surface samples were measured 18:30 (pre), 19:30 (post), 20:30 (60 min), and 21:30 (120 min). Secretory immunoglobulin A (SIgA) and human ß-defensin 2 (HBD-2) concentrations were measured using an enzyme-linked immunosorbent assay (ELISA). SIgA concentration at pre was significantly higher than at post, 60 min and 120 min (p < 0.05). HBD-2 concentration at post and 120 min was significantly higher than at pre (p < 0. 05). Moisture content of the stratum corneum was significantly higher at post than at pre, 60 min, and 120 min (p < 0.05). On the chest, moisture content of the stratum corneum was significantly lower at 120 min than at pre (p < 0.05). The number of staphylococci was significantly higher at post than at pre (p < 0.05), and tended to be higher at 60 min than at pre on the chest (p = 0. 08). High-intensity endurance exercise might depress the immune barrier and physical barrier and enhance the risk of skin infection. On the other hand, the biochemical barrier increases after exercise, and our findings suggest that this barrier might supplement the compromised function of other skin barriers. Key pointsThe immune barrier and physical barrier might be depressed and the risk of skin infection might be enhanced by high-intensity endurance exercise.The biochemical barrier increases after high-intensity endurance exercise and might supplement the compromised function of other skin barriers.We recommend that athletes maintain their skin surface in good condition, for example, by showering immediately after sports activities and using moisturizers.