The fan cooling vest use reduces thermal and perceptual strain during outdoor exercise in the heat on a sunny summer day.

The fan cooling vest is coming into very common use by Japanese outdoor manual workers. We examined that to what extent using this vest reduces thermal strain and perception during outdoor exercise in the heat on a sunny summer day. Ten male baseball players in high school conducted two baseball training sessions for 2-h with (VEST) or without (CON) a commercially available fan cooling vest on a baseball uniform. These sessions commenced at 10 a.m. on separate days in early August. The fan airflow rate attached the vest was 62 L·s-1. Neither ambient temperature (Mean ± SD: VEST 31.9 ± 0.2°C; CON 31.8 ± 0.7°C), wet-bulb globe temperature (VEST 31.2 ± 0.4°C; CON 31.4 ± 0.5°C) nor solar radiation (VEST 1008 ± 136 W·m-2; CON 1042 ± 66 W·m-2) was different between trials. Mean skin temperature (VEST 34.5 ± 1.1°C; CON 35.1 ± 1.4°C), infrared tympanic temperature (VEST 38.9 ± 0.9°C; CON 39.2 ± 1.2°C), heart rate (VEST 127 ± 31 bpm; CON 139 ± 33 bpm), body heat storage (VEST 140 ± 34 W·m-2; CON 160 ± 22 W·m-2), thermal sensation (- 4-4: VEST 0 ± 2; CON 3 ± 1) and rating of perceived exertion (6-20: VEST 11 ± 2; CON 14 ± 2) were lower in VEST than CON (all P < 0.05). Total distance measured with a global positioning system (VEST 3704 ± 293 m; CON 3936 ± 501 m) and body fluid variables were not different between trials. This study indicates that the fan cooling vest use can reduce thermal strain and perception during outdoor exercise in the heat on a sunny summer day. Cooling with this vest would be effective to mitigate thermal risks and perceptual stress in athletes and sports participants under such settings.

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.

History, Knowledge, and Education of Sport-Related Concussion Among College Athletes in Japan.

CONTEXT: Limited studies have investigated sports-related concussion (SRC) awareness and knowledge among athletes in Japan. SRC research is scarce among Asians compared to North American and European cohorts. OBJECTIVE: We aimed to examine previous SRC history, level of SRC knowledge, and previous exposure to SRC education among collegiate athletes in Japan by the level of contact and access to medical staff. DESIGN: Cross-sectional study. SETTING: Single university study in XXX. PATIENTS OR OTHER PARTICIPANTS: A total of 2,103 athletes (48 varsity teams) were contacted to participate in an anonymous survey. Data from athletes with (1) SRC history in the past 3 months, (2) persistent SRC symptoms, (3) non-traditional sports, and (4) incomplete surveys were excluded. As a result, data from 593 athletes representing 43 varsity teams were included in this analysis. MAIN OUTCOME MEASURES: Outcome measures were level of contact (contact [CON], limited contact [LTD], noncontact [NC]), access to medical staff (MEDYES, MEDNO), SRC knowledge (maximum score of 49), and previous SRC history (self-report; yes, no), and previous SRC education (self-report; EDUYES, EDUNO). RESULTS: The average SRC knowledge total score was 33.4 ± 6.1 (range, 18-48). Knowledge score in CON was higher than LTD and NC (p<.001), and in MEDYES than MEDNO (median, MEDyes= 34.0, MEDNO= 32.0; U=27841.5, p<.001). SRC history was statistically different by the level of contact (χ2 [2] =27.95, p<.001) and by access to medical staff (χ2 [1] =4.5, p=.034). The presence of SRC history and previous SRC education contributed to higher SRC knowledge, independent of the level of contact and access to medical staff (p<.001). CONCLUSIONS: Japanese athletes who participated in CON sports had a higher prevalence of SRC history, higher knowledge, and greater exposure to SRC education than those in LTD or NC. Access to medical staff was associated with higher SRC knowledge.

Exertional Heat Stroke Survival at the Falmouth Road Race: 180 New Cases With Expanded Analysis.

CONTEXT: A high number of exertional heat stroke (EHS) cases occur during the Falmouth Road Race. OBJECTIVES: To extend previous analyses of EHS cases during the Falmouth Road Race by assessing or describing (1) EHS and heat exhaustion (HE) incidence rates, (2) EHS outcomes as they relate to survival, (3) the effect of the environment on these outcomes, and (4) how this influences medical provider planning and preparedness. DESIGN: Descriptive epidemiologic study. SETTING: Falmouth Road Race. PATIENTS OR OTHER PARTICIPANTS: Patients with EHS or HE admitted to the medical tent. MAIN OUTCOME MEASURE(S): We obtained 8 years (2012 to 2019) of Falmouth Road Race anonymous EHS and HE medical records. Meteorologic data were collected and analyzed to evaluate the effect of environmental conditions on the heat illness incidence (exertional heat illness [EHI] = EHS + HE). The EHS treatment and outcomes (ie, cooling time, survival, and discharge outcome), number of HE patients, and wet bulb globe temperature (WBGT) for each race were analyzed. RESULTS: A total of 180 EHS and 239 HE cases were identified. Overall incidence rates per 1000 participants were 2.07 for EHS and 2.76 for HE. The EHI incidence rate was 4.83 per 1000 participants. Of the 180 EHS cases, 100% survived, and 20% were transported to the emergency department. The WBGT was strongly correlated with the incidence of both EHS (r2 = 0.904, P = .026) and EHI (r2 = 0.912, P = .023). CONCLUSIONS: This is the second-largest civilian database of EHS cases reported. When combined with the previous dataset of EHS survivors from this race, it amounts to 454 EHS cases resulting in 100% survival. The WBGT remained a strong predictor of EHS and EHI cases. These findings support 100% survival from EHS when patients over a wide range of ages and sexes are treated with cold-water immersion.

Heat Preparation and Knowledge at the World Athletics Race Walking Team Championships Muscat 2022.

PURPOSE: To assess elite racewalkers' preparation strategies, knowledge, and general practices for competition in the heat and their health status during the World Athletics Race Walking Teams Championships (WRW) Muscat 2022. METHODS: Sixty-six elite racewalkers (male: n = 42; mean age = 25.8 y) completed an online survey prior to WRW Muscat 2022. Athletes were grouped by sex (males vs females) and climate (self-reported) they live/trained in (hot vs temperate/cold), with differences/relationships between groups assessed. Relationships between ranking (medalist/top 10 vs nonmedalist/nontop 10) and precompetition use of heat acclimation/acclimatization (HA) were assessed. RESULTS: All surveyed medalists (n = 4) implemented, and top 10 finishers were more likely to report using (P = .049; OR = 0.25; 95% CI, 0.06%-1%), HA before the championships. Forty-three percent of athletes did not complete specific HA training. Females (8% [males 31%]) were less likely to have measured core temperature (P = .049; OR = 0.2; 95% CI, 0.041-0.99) and more likely to not know expected conditions in Muscat (42% vs 14%; P = .016; OR = 4.3; 95% CI, 1%-14%) or what wet bulb globe temperature is (83% vs 55%; P = .024; OR = 4.1; 95% CI, 1%-14%). CONCLUSIONS: Athletes who implemented HA before the championships tended to place better than those who did not. Forty-three percent of athletes did not prepare for the expected hot conditions at the WRW Muscat 2022, primarily attributed to challenges in accessing and/or cost of equipment/facilities for HA strategies. Further efforts to bridge the gap between research and practice in this elite sport are needed, particularly in female athletes.

Thermal strain is greater in the late afternoon than morning during exercise in the gym without airflow and air conditioning on a clear summer day.

Introduction: There are no reports examining the time-of-day effect on team training sessions in the gym without airflow and air conditioning on thermal strain in the summer heat. We investigated this effect during badminton training sessions on a clear summer day. Methods: Nine male high school badminton players (Mean ± SD; age 17.1 ± 0.6 y, height 171 ± 4 cm, body mass 59 ± 7 kg) completed two 2.5-h badminton training sessions in the gym without airflow and air conditioning. The training sessions were started at 0900 h (AM) and 1600 h (PM) on separate days in August. Skin temperatures (chest, triceps, thigh, calf), infrared tympanic temperature, heart rate, thermal sensation and rating of perceived exertion were recorded at rest and at regular intervals during the sessions. Results: Indoor and outdoor environmental heat stress progressively increased in AM and decreased in PM during the sessions. Ambient temperature (AM 30.1 ± 0.9°C; PM 33.2 ± 1.0°C: P < 0.001) and wet-bulb globe temperature (AM 28.1 ± 0.5°C; PM 30.0 ± 0.9°C: P = 0.001) during the sessions in the gym were higher in PM than AM. Mean skin temperature (AM 34.2 ± 1.0°C; PM 34.7 ± 0.7°C: P < 0.001), infrared tympanic temperature (AM 37.8 ± 0.5°C; PM 38.1 ± 0.4°C: P = 0.001) and thermal sensation (AM 2.7 ± 1.4; PM 3.3 ± 1.0: P < 0.001) during the sessions were higher in PM than AM. Body heat storage (AM 159 ± 30 W·m-2; PM 193 ± 30 W·m-2: P < 0.05) was greater in PM than AM. There were no time-of-day differences in the average heart rate (AM 75 ± 4% age-predicted maximal heart rate; PM 76 ± 5 age-predicted maximal heart rate: P = 0.534), body mass loss (AM 0.6 ± 0.3 kg; PM 0.8 ± 0.2°C: P = 0.079), the volume of water ingested (AM 1.5 ± 0.1 L; PM 1.6 ± 0.3 L: P = 0.447) and rating of perceived exertion (AM 16 ± 2; PM 16 ± 3: P = 0.281). Conclusions: This study indicates greater thermal strain in PM trial than in AM trial during team training sessions in the gym without airflow and air conditioning on a clear summer day. Therefore, athletes and coaches of indoor sports should perceive that athletes may be exposed to a greater risk for thermal strain in the late afternoon from 1600 h than in the morning from 0900 h during the sessions in the gym under these conditions.

Question Format Matters: Do Athletes Really Know the Signs and Symptoms of a Sport-Related Concussion?

Authors of previous studies commonly used a multiselect checklist method to assess an athlete's ability to recognize true sport-related concussion (SRC) signs and symptoms (S&S) among incorrect distractor options. However, this may overinflate the evaluation of participants' knowledge because the multiselect method does not test athletes' ability to retrieve knowledge from their long-term memory. To examine this hypothesis, we sent an online survey to registered members of the Japan Lacrosse Association (n = 8530) to assess differences in reported SRC S&S by open-ended-question and multiselect formats. We also evaluated whether previous exposure to SRC education and a history of SRC influenced athletes' SRC S&S knowledge. The numbers and proportions of responses were calculated using descriptive statistics. The Pearson correlation was calculated to analyze the relationship between scores from the 2 question formats. Unpaired-samples t tests were conducted to compare the mean scores for each question format by previous SRC education and history of diagnosed SRC. Odds ratios were computed to express the relationship between the proportion of correct answers by question format per symptom. The response rate of the survey was 35.9% (n = 3065), and scores from the 2 question formats were correlated (r = 0.34, 95% CI = 0.31, 0.37; P < .001). For both question formats, athletes with previous exposure to SRC education and a history of SRC had a greater number of correct answers; however, the mean differences were trivial. Researchers and clinicians should acknowledge the difference between multiselect (recognition) and open-ended (free recall) formats when assessing one's understanding of SRC and managing athletes with a suspected SRC.

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.

Epidemiology of sudden cardiac death and sudden cardiac arrest with resultant disability during high school organized sport in Japan.

OBJECTIVES: To examine the incidence and survival rates of sudden cardiac arrest that were documented during school organized sports in Japan. DESIGN: Retrospective cohort study. METHODS: Insurance claim data of cardiac events (sudden cardiac death and sudden cardiac arrest with resultant disabilities) that occurred during Japanese high school organized sports between 2009 and 2018 were retrieved. Participation data from All Japan High School Athletic Federation and Japan High School Baseball Federation were used for incidence rate calculations. Incidence rate ratios with 95 % confidence interval were calculated to compare the risk by sports and sex. The survival rate was calculated with the proportion of resuscitated cases to total number of cardiac events in this dataset. RESULTS: A total of 55 cardiac events (25 survivors and 30 deceased) were identified in the dataset. The majority affected male student-athletes (92.7 %). The frequency and incidence rate of cardiac events were highest in male baseball (n = 16 [29.1 %], incidence rate: 0.91 per 100,000 athlete-years). Incidence rate ratio revealed that male basketball (2.19, 95 % confidence interval: 1.04-4.60), male baseball (2.31, 95 % confidence interval: 1.32-4.03), and first-year male baseball (4.11, 95 % confidence interval: 2.10-8.07) had significantly higher risk of cardiac events, compared to the overall incidence rate (0.38 per 100,000 athlete-years). The survival rates were 37.5 % in the first half (2009-2013) and 56.5 % in the latter half (2014-2018) of the study period. CONCLUSIONS: The risk of cardiac events was highest in male, baseball, first-year student-athletes. Rapid AED application by bystanders should be advocated to enhance better survival.

Athlete Medical Services at the Marathon and Race Walking Events During Tokyo 2020 Olympics.

Epidemiological data from race walk and marathon events suggest that a high incidence rate of exertional heat illness is associated with high ambient temperature and relative humidity. The 2020 Summer Olympics in Tokyo was no exception, which led the organizing committee to relocate the race walk and marathon competitions to Sapporo, which was predicted to experience much milder heat. Nonetheless, during the Games, Sapporo recorded the highest daytime ambient temperature in the past 97 years, with consecutive days over 30°C from July 22nd to August 7th, 2021. Five events (men's and women's 20 km race walk, men's 50 km race walk, women's and men's marathon) were held in Sapporo from August 5th to August 8th, 2021. The percentage of athletes who did not finish (DNF) in each event was 8.8% in men's 20 km race walk, 20.3% in men's 50 km race walk, 8.6% in women's 20 km race walk, 17.1% in women's marathon and 28.3% in men's marathon. A total of fifty athletes were transferred to the athlete medical station: 28 athletes completed the race (i.e., collapsed after finish line), while 24 were DNF athletes transported from the course. Forty-eight (96%) of athletes who were admitted to the athlete medical station exhibited signs and symptoms of exertional heat illness. Two athletes diagnosed with exertional heat stroke and three athletes diagnosed with severe heat exhaustion (rectal body temperature >39.5°C with or without central nervous system disturbance) were cooled using whole-body cold water immersion at the heat deck located within the athlete medical station. All athletes who were cooled successfully recovered without any complications. These athletes required an average of 14 ± 9.4 min (range, 6-30 min) to cool their rectal temperature below 39°C. These results show the importance for event organizers to prepare strategies to keep athletes cool, such as an ample amount of ice and water to supply whole-body cold water immersion.

Sudden Death in High School Athletes: A Case Series Examining the Influence of Sickle Cell Trait.

ABSTRACT: Athletes with sickle cell trait (SCT) have up to a 37-fold increased risk of exercise-related death. Exertional collapse associated with sickle cell trait (ECAST) is uncommon but can lead to exercise-related death due to exertional sickling. We present a case series of fatal ECAST in high school athletes aged 14 to 16 years. All 3 athletes experienced collapse during practice sessions with muscle pain or weakness. Upon evaluation at the hospital, the athletes had a significant metabolic acidosis that did not respond as expected to fluid resuscitation. Admitting diagnoses for the athletes included exertional heat stroke or dehydration. All 3 athletes had profound rhabdomyolysis leading to acute renal failure, worsening metabolic acidosis, and hyperkalemia. They rapidly progressed to disseminated intravascular coagulation, multiorgan system failure, and death. The autopsies of all 3 athletes showed extensive sickle cell vaso-occlusion involving the spleen liver, and muscles. Final clinical and pathologic diagnosis supported ECAST with fatal exertional rhabdomyolysis. Exertional collapse associated with sickle cell trait is an uncommon but potentially deadly condition that is often underrecognized or misdiagnosed as exertional heat stroke. The development of ECAST is thought to be multifactorial with exercise intensity, recent illness, and exercising conditions (ie, heat and altitude). Prevention should be the primary goal for athletes with SCT through exercise modification, education of precipitation factors, and cessation of exercise with recent illness. Athletes with suspected ECAST should undergo aggressive resuscitation with a low threshold for early transfer to a tertiary care facility for further management and potential hemodialysis.

Prehospital management of exertional heat stroke at sports competitions for Paralympic athletes.

OBJECTIVES: To adapt key components of exertional heat stroke (EHS) prehospital management proposed by the Intenational Olympic Committee Adverse Weather Impact Expert Working Group for the Olympic Games Tokyo 2020 so that it is applicable for the Paralympic athletes. METHODS: An expert working group representing members with research, clinical and lived sports experience from a Para sports perspective reviewed and revised the IOC consensus document of current best practice regarding the prehospital management of EHS. RESULTS: Similar to Olympic competitions, Paralympic competitions are also scheduled under high environmental heat stress; thus, policies and procedures for EHS prehospital management should also be established and followed. For Olympic athletes, the basic principles of EHS prehospital care are: early recognition, early diagnosis, rapid, on-site cooling and advanced clinical care. Although these principles also apply for Paralympic athletes, slight differences related to athlete physiology (eg, autonomic dysfunction) and mechanisms for hands-on management (eg, transferring the collapsed athlete or techniques for whole-body cooling) may require adaptation for care of the Paralympic athlete. CONCLUSIONS: Prehospital management of EHS in the Paralympic setting employs the same procedures as for Olympic athletes with some important alterations.

Heat Safety in the Workplace: Modified Delphi Consensus to Establish Strategies and Resources to Protect the US Workers.

The purpose of this consensus document was to develop feasible, evidence-based occupational heat safety recommendations to protect the US workers that experience heat stress. Heat safety recommendations were created to protect worker health and to avoid productivity losses associated with occupational heat stress. Recommendations were tailored to be utilized by safety managers, industrial hygienists, and the employers who bear responsibility for implementing heat safety plans. An interdisciplinary roundtable comprised of 51 experts was assembled to create a narrative review summarizing current data and gaps in knowledge within eight heat safety topics: (a) heat hygiene, (b) hydration, (c) heat acclimatization, (d) environmental monitoring, (e) physiological monitoring, (f) body cooling, (g) textiles and personal protective gear, and (h) emergency action plan implementation. The consensus-based recommendations for each topic were created using the Delphi method and evaluated based on scientific evidence, feasibility, and clarity. The current document presents 40 occupational heat safety recommendations across all eight topics. Establishing these recommendations will help organizations and employers create effective heat safety plans for their workplaces, address factors that limit the implementation of heat safety best-practices and protect worker health and productivity.

Comparison of the effect of post-exercise cooling with ice slurry ingestion between males and females.

This study aimed to compare the effects of ice slurry ingestion on post-exercise cooling in males and females. Twenty-four healthy adults (male n = 12; body weight [BW], 65.8 ± 10.3 kg; female, n = 12; BW, 58.2 ± 10.0 kg) participated in this study. Participants ingested 7.5 g/kg of either ice slurry at -1 °C (ICE) or control fluid at 20 °C (CON) during recovery after cycling at 55% VO2max until the rectal temperature reached 38.5 °C or exhaustion in a hot environment (controlled at 38 °C, 40% relative humidity). Rectal (Tre) and skin (Tsk) temperature, ratings of thermal sensation (TS), thermal comfort (TC), heart rate (HR), mean arterial pressure (MAP), and whole body sweat loss (WBSL) were measured 60 min after exercise. Ice slurry ingestion reduced Tre and TS and improved post-exercise hypotension only in females (p < 0.05). In comparison, males did not receive cooling effect from post- exercise cooling with ice slurry ingestion. WBSL tended to be lower in ICE than CON in males (ICE, 454.3 ± 172.3 g; CON, 539.7 ± 157.2 g; p = 0.065). In conclusion, sex differences were observed in the effects of post-exercise cooling with ice slurry ingestion.

Epidemiology of sports-related fatalities during organized school sports in Japanese high schools between 2009 and 2018.

Limited literature has investigated epidemiology of sports-related fatalities during high school organizes sports in Japan. Therefore, the purposes of this study are to determine the frequency and incidence rate of sports-related fatalities in Japanese high schools by cause and sports, and to examine the type of on-site first responder. Insurance claim data of sports-related fatalities in Japanese high schools reported to Japan Sports Council Injury and Accident Mutual Aid Benefit System between 2009 and 2018 were retrieved as the primary data source. All fatalities were classified into direct or indirect type by the reported etiology and further categorized into cardiac-related, head and neck injury, exertional heat stroke (EHS), or other. Frequency and incidence rate were calculated by cause of death and sports, and incidence rates were expressed per 100,000 athlete-years (AY) with 95% confidence interval (CI). Information regarding first responder to the incident was also retrieved and examined by frequency. A total of 63 sports-related fatalities were analyzed. The overall incidence rate was 0.45 (95%CI = 0.25-0.65) per 100,000AY. The incidence rates of direct and indirect fatalities declined from 0.36 and 0.50 per 100,000AY to 0.28 and 0.00 per 100,000AY, respectively. The leading cause of deaths was cardiac-related (n = 30/63, 47.6%), followed by head and neck injury (n = 15/63, 23.8%) and EHS (n = 14/63, 22.2%). The number of fatalities was highest in male baseball (n = 12/63, 19.0%) and the incidence rate was highest in male judo (4.79 per 100,000 AY, 95%CI: 0.68-8.15). Coach was the most frequently reported first responder onsite (n = 52/63, 82.5%). Medically trained personnel were involved in onsite care in two cases (3.2%). In conclusion, the occurrence of sports-related fatalities has declined over time from 2009 to 2018. To deliver appropriate medical care onsite for better survival, employment of medically trained personnel should be promoted in high school sports setting in Japan.