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Exertional heat fatalities in Australian sport and recreation

      Abstract

      Objectives

      To describe the number and case characteristics of sport and recreation-related exertional heat deaths in Australia and summarise recommendations derived from case narratives.

      Design

      Descriptive, population-based, retrospective cohort study.

      Methods

      Cases were identified using the National Coronial Information System (NCIS) through multiple search strategies comprising queries, keywords and cause of death codes. Cases were included where there was evidence that the deceased was actively engaged in sport or recreation and exertional heat illness was causal or contributory to the death. Data extraction were performed independently, in duplicate, to ensure accuracy. Descriptive statistics are used to report deceased's socio-demographic characteristics, incident characteristics, type of sport/recreational activity and time sequence of events. Content analysis is used to summarise recommendations.

      Results

      Thirty-eight deaths (males n = 29, 74%; median age = 40 years, range 8–77) were identified during the study period (2001 to 2018), with 22 recommendations for five cases. Two cases occurred during organised sport and 36 during active recreation, of which 27 were in hiking. Eleven (29%) individuals were international visitors. There were 22 recommendations across 5 cases presented, with a focus on education and training.

      Conclusions

      Exertional heat deaths in outdoor recreation in Australia were far more prevalent than cases in organised sport. The largest proportion of deaths occurred in hiking with two populations featuring: males aged 15–45 years and international visitors. Considering the incident characteristics and time sequence of events, measures such as early recognition of symptoms, provision of first aid and timely access to emergency medical care are important to prevent fatalities.

      Keywords

      Practical implications

      • Two distinct populations who had a fatal heat related death were identified — males aged 15–45 years and international visitors. Any safety and awareness information that is developed must be relevant and accessible to these populations.
      • Most fatalities occurred during hiking on days of high temperature and high humidity. Clear and simple messaging of ‘hiking on days of extreme heat is strongly discouraged’ should be promoted.
      • Delays in accessing medical care contributed to many fatalities. Recognition of signs/symptoms and rapid emergency assistance is crucial to survival.
      • Recommendations were focused on organisational influences. Yet most cases occurred in an environment where such organisations had no direct influence on the deceased participant. Renewed strategies are needed ideally driven by state-or nationwide organisations.

      1. Background

      The 2019–2020 Australian Summer of high temperatures, bushfires and smoke significantly impacted participation in sport and recreation across the country.
      • Australian Bureau of Meteorology and Commonwealth Scientific and Industrial Research Organisation (CSIRO)
      State of the Climate 2020.
      These events raised concern that as extreme temperatures become more common, safe participation in outdoor sport and recreation will become increasingly challenging.
      • May C.
      • on behalf of Clearinghouse for Sport
      Heat illness in sport and exercise (website).
      Existing evidence has shown that an increased number of hospital admissions are reported during heat waves in Australia.
      • Khalaj B.
      • Lloyd G.
      • Sheppeard V.
      • et al.
      The health impacts of heat waves in five regions of New South Wales, Australia: a case-only analysis.
      Most of these cases are attributed to the classic form of heat injury that is linked directly with environmental conditions and commonly seen in elderly and infant populations.
      In younger and more active populations, morbidity from heat tends to be exertional, meaning it not only occurs due to high environmental temperatures but also through the body's increased metabolic activity that results in abnormal or excessive core body temperature.
      • O'Connor F.G.
      • Casa D.J.
      Exertional heat illness in adolescents and adults: epidemiology, thermoregulation, risk factors, and diagnosis.
      Exertional heat illness occurs on a spectrum from mild (e.g. cramps, nausea) to moderate (e.g. exercise associated exhaustion and collapse) to severe or catastrophic (e.g. heat strokes with multi organ failure, death).
      • O'Connor F.G.
      • Casa D.J.
      Exertional heat illness in adolescents and adults: epidemiology, thermoregulation, risk factors, and diagnosis.
      Epidemiological studies of heat injury in sport were recently summarised in a systematic review, where an increased trend in deaths over the last three decades was noted.
      • Gamage P.J.
      • Fortington L.V.
      • Finch C.F.
      Epidemiology of exertional heat illnesses in organised sports: a systematic review.
      The review also highlighted a general lack of detailed sport-specific information on cases, particularly outside of the USA.
      There is potentially a high risk of death from heat in Australian sport and recreation, due to the region's climate and generally strong levels of participation in outdoor sport and recreation activities. To continue to promote safe participation in outdoor events, an understanding of past heat-related deaths is important. This information will help to identify sports and populations at highest risk as well as opportunities for prevention and improved emergency responses. Accordingly, the aim of this study was to describe the incidence, socio-demographic, incident and response characteristics of EHI cases in Australia between 2001 and 2019. Specifically, alongside epidemiological case data, we focus on the content of recommendations from medico-legal investigations reported to, or by, the Coroner.

      2. Methods

      A population-based retrospective cohort study was performed to examine all cases of exertional heat-related deaths in sport and recreation notified to Australian Coroners from 1 January 2001 to 31 December 2018. This study was approved by the Justice Human Research Ethics Committee CF/19/24669 and Western Australia Coronial Ethics Committee.
      The primary data source for this study was the National Coronial Information System (NCIS). The NCIS is an internet-based data repository of all deaths notified to Australian Coroners since July 2000 (2001 in Queensland). The NCIS stores coded and free text information on the deceased's socio-demographic characteristics; activity; location (at the time of the incident and usual place of residence); mechanism and cause of death. Up to four full-text reports (1. police narrative of circumstances; 2. autopsy report; 3. toxicology report; and 4. Coroners' finding) may be attached for each case. The NCIS is accessible to authorised users, approved by the Justice Human Research Ethics Committee.
      Searches of the NCIS are performed by building a query or using key words or codes. Three independent searches of the NCIS were performed (Supplementary Table 1). Two search strategies, the query design and key word search, were developed in consultation with a staff member of the NCIS Unit. The third search was of the International Classification of Diseases (ICD-10) external cause of death code X30 exposure to excessive natural heat. Results of the three searches were combined and duplicates deleted to form a unit record dataset. Three authors (AC, LB, LF) reviewed each case against the inclusion criteria and any uncertainty on inclusion was resolved via group discussion.
      Cases that met the following eligibility criteria were included in the study:
      • the death occurred between 1 January 2001 and 31 December 2018 in Australia;
      • the death investigation has been completed by the Coroner and data coded in the NCIS by 1 March 2019;
      • there was evidence that the deceased was actively engaged in a sport or recreation/leisure activity at the time of the incident;
      • exertional heat illness was determined as causal or contributory to death; and
      • the deceased was considered as active at the time when signs/symptoms commenced or shortly beforehand.
      Excluded were cases that were not clearly active with intent of fitness or competition, such as children trapped in cars or older people engaged in tasks at home. This exclusion was based on these cases requiring a different prevention approach from that cases that were ultimately included.
      For cases that met the inclusion criteria the NCIS record was reviewed and up to 67 data items were extracted into a dataset derived by the research team (Supplementary Table 2) using Microsoft Excel. Data items extracted related to: socio-demographic characteristics of the deceased; comorbidities of deceased; sport/recreational activity data; incident data including date and location; time sequence of events; pre-hospital care; and cause of death. Two authors independently performed the data extraction (AC, LF). Uncertainty on any variables was resolved via discussion with a third author (LB).
      Descriptive statistical analyses were performed to examine the frequency of deaths with consideration to the deceased's socio-demographic characteristics (age, gender, state of residence); incident-related characteristics (state, year, season, place of incident, weather and conditions); type of sport/recreational activity; and cause of death (both Coroner specified cause of death and all recorded diagnoses in international statistical classification of diseases and related health problems, tenth revision (ICD-10)).
      A descriptive content analysis was used for summarising Coroners' reports to identify key findings and recommendations among the text documents.
      • Bengtsson M.
      How to plan and perform a qualitative study using content analysis.
      The analysis used an a priori design with the themes based around steps for identifying public health actions from coronial data.
      • Bugeja L.
      • McClure R.J.
      • Ozanne-Smith J.
      • et al.
      The public policy approach to injury prevention.
      All text was initially coded by looking for four themes:
      • Target population (beneficiary) of a finding or recommendation
      • Organisation that needs to act on a recommendation
      • A contributory factor - defined as aspects of behaviour or lifestyle, environmental exposure, or an inherited characteristic, which is known to be associated with health-related condition(s) considered important to prevent.
      • A countermeasure - any intervention that addresses a specific risk factor for injury.
      Specific countermeasures strategies were then coded across four themes according to whether they addressed:
      • Laws & regulation
      • Training & education
      • Equipment
      • Behaviours
      Finally, the timing of the strategy, addressing pre-event, event or post-event factors was determined.
      All coding was undertaken by two authors (AC and LF). A third author (LB) revised all codes that differed for a binding decision. Where a more medically derived decision was required, author PG was consulted. Example text is presented to help with understanding the content that makes up each theme. Text is redacted in places to remove potential identifiers of specific people or organisations.

      3. Results

      There were 38 exertional heat-related deaths in Australia related to active sport or recreation identified. Cases were most frequently male (n = 29, 74%) and ages ranged from 8 to 77 years (median 40 years) (Table 1). At least one case was recorded for residents from all States/Territories, the majority residing in Western Australia (WA) (n = 7), New South Wales (NSW) (n = 5) and Queensland (QLD) (n = 5). Most deaths occurred in recreation (n = 36, 95%), including 27 hiking deaths. Two deaths occurred in organised sport. Eleven (29%) deaths were international visitors to Australia.
      Table 1Socio-demographic and incident characteristics of sport/recreational EHI deaths, Australia, 2001–2018.
      n%
      Characteristics of individuals
      Cases38100
      Sex
       Male2974.4
       Female925.6
      Age (median, range)40, 8–77
       ≤205
       21–4016
       41–608
       >609
      Country of origin
       Australia2771.1
       Overseas1129.0
      State of usual residence
       ACT
      For protection of individual privacy, data are supressed where fewer than five (1–4) cases are reported. If there is only one variable < 5, a second cell is also suppressed.
      For protection of individual privacy, data are supressed where fewer than five (1–4) cases are reported. If there is only one variable < 5, a second cell is also suppressed.
       NSW513.2
       NT
      For protection of individual privacy, data are supressed where fewer than five (1–4) cases are reported. If there is only one variable < 5, a second cell is also suppressed.
      For protection of individual privacy, data are supressed where fewer than five (1–4) cases are reported. If there is only one variable < 5, a second cell is also suppressed.
       QLD513.2
       SA
      For protection of individual privacy, data are supressed where fewer than five (1–4) cases are reported. If there is only one variable < 5, a second cell is also suppressed.
      For protection of individual privacy, data are supressed where fewer than five (1–4) cases are reported. If there is only one variable < 5, a second cell is also suppressed.
       TAS
      For protection of individual privacy, data are supressed where fewer than five (1–4) cases are reported. If there is only one variable < 5, a second cell is also suppressed.
      For protection of individual privacy, data are supressed where fewer than five (1–4) cases are reported. If there is only one variable < 5, a second cell is also suppressed.
       VIC
      For protection of individual privacy, data are supressed where fewer than five (1–4) cases are reported. If there is only one variable < 5, a second cell is also suppressed.
      For protection of individual privacy, data are supressed where fewer than five (1–4) cases are reported. If there is only one variable < 5, a second cell is also suppressed.
       WA718.4
      Characteristics of incident
      State of incident in Australia
       ACT00
       NSW513.2
       NT821.1
       QLD513.2
       SA
      For protection of individual privacy, data are supressed where fewer than five (1–4) cases are reported. If there is only one variable < 5, a second cell is also suppressed.
      For protection of individual privacy, data are supressed where fewer than five (1–4) cases are reported. If there is only one variable < 5, a second cell is also suppressed.
       TAS
      For protection of individual privacy, data are supressed where fewer than five (1–4) cases are reported. If there is only one variable < 5, a second cell is also suppressed.
      For protection of individual privacy, data are supressed where fewer than five (1–4) cases are reported. If there is only one variable < 5, a second cell is also suppressed.
       VIC
      For protection of individual privacy, data are supressed where fewer than five (1–4) cases are reported. If there is only one variable < 5, a second cell is also suppressed.
      For protection of individual privacy, data are supressed where fewer than five (1–4) cases are reported. If there is only one variable < 5, a second cell is also suppressed.
       WA1129.0
      Year of incident
       2001–2006615.8
       2007–20121642.1
       2013–20181642.1
      Season of incident
       Summer2155.3
       Autumn/Winter613.2
       Spring1129.0
      Place of death
       At place of incident2976.3
       In hospital or in transit718.4
      Elapsed time between symptom identification and death
       <1 h00
       1–5 h718.4
       >5 h923.7
       Undetermined
      Unable to be ascertained from the data available.
      1026.3
       Not stated/available615.8
      Evidence of contributing co-morbid conditions
       Yes1231.6
       No2463.2
      a For protection of individual privacy, data are supressed where fewer than five (1–4) cases are reported. If there is only one variable < 5, a second cell is also suppressed.
      b Unable to be ascertained from the data available.
      For 17 (45%) cases the state of death differed from state of residence. Most fatal incidents occurred in WA (n = 11, 29%), followed by Northern Territory (NT) (n = 8), QLD (n = 5) and NSW (n = 5). Deaths occurred most frequently in the Summer (n = 21, 55%) or Spring (n = 11, 29%) months. Potential contributory comorbidities were noted in the records of 12 cases. These included a high BMI/obesity, mental health or heart/cardiovascular conditions, or regular medication use. Where information was available on the timing of symptom onset and death (n = 22, 57.9%), the duration between recognition of first symptoms to time of death was greater than 5 h in 9 cases (41%, out of 22 known cases). In most cases (n = 29, 76%), the place of death was recorded as the place of the incident.
      The primary cause of death was variously described by Coroners as heat stroke, heat exhaustion, hyperthermia and exposure (Supplementary Table 3). In many cases other causes were listed as contributory or present, including hyponatraemia or dehydration (n = 8); with medication, chronic or coronary disease, obesity or similar (n = 7); and with infection (different types noted), sepsis or organ failure (n = 7). The ICD-10 classification of the underlying cause of death assigned by the Australian Bureau of Statistics was recorded as a variant of X30 “exposure to excessive natural heat (at other specified places)” for 26 cases. Up to five ICD-10 codes were assigned to describe other diagnoses. There were 33 unique codes assigned across all cases.
      There were 22 recommendations (range of 0–10) specified across 5 cases (Table 2, Table 3). The target population and organisation were mentioned equally (77% each), pre-event strategies were most common (82%), and education and training was the basis of most strategies (63.6%).
      Table 2Overview of target population, timing and strategies identified in the coronial data for sport and recreation settings in the prevention or management of fatalities from exertional heat illness.
      VariableDescription or example of variableSport & recreation
      Overview of data
       Cases includedTotal number of fatalities identified38
       InquestWas an inquest held (court hearing)5 (13.2%)
       Number of recommendations (median, range)The number of separate recommendations identifiable in the text22 (2.5, 0–10)
      Target of finding
       Population of intervention“…provided to sports trainers and other first responders should be …”17 (77.3%)
       Organisation targeted“…that a working party (including the Ambulance Service, Police Service, Fire Brigade, National Parks and Wildlife and Communications Service Point) be established to …”17 (77.3%)
       Contributory factors“…travelling to areas outside the metropolitan area…”11 (50.0%)
       Countermeasure“the importance of carrying sufficient quantities of water and adequately planning overnight walks…”17 (77.3%)
      Strategies
       Laws & regulations“….”8 (36.4%)
       Environment“…utilize communication equipment to check on current weather forecasts prior to each day's activities and periodically throughout the day …”
      For protection of individual privacy, data are supressed where fewer than five (1–4) cases are reported. If there is only one variable < 5, a second cell is also suppressed.
       Education & training“…to deliver the appropriate education campaign and update information sources.”14 (63.6%)
       Behaviour modification“…the activity should be postponed to a cooler condition (or cooler part of the day) or postponed to another day.”
      For protection of individual privacy, data are supressed where fewer than five (1–4) cases are reported. If there is only one variable < 5, a second cell is also suppressed.
      Timing of strategy
       Pre event“prior to each day's activities…”18 (81.8%)
       Event“recommend that all participants have with them…”
      For protection of individual privacy, data are supressed where fewer than five (1–4) cases are reported. If there is only one variable < 5, a second cell is also suppressed.
       Post-event
      For protection of individual privacy, data are supressed where fewer than five (1–4) cases are reported. If there is only one variable < 5, a second cell is also suppressed.
      a For protection of individual privacy, data are supressed where fewer than five (1–4) cases are reported. If there is only one variable < 5, a second cell is also suppressed.
      Table 3Strategies identified for sport and recreation settings in the prevention or management of fatalities from exertional heat illness.
      ThemeSport & recreation
      Laws & governanceResponsibility of recreation providers
      • Providers need to ensure their clients are well instructed in the dangers which can arise once there is a loss of visual or auditory contact. Loss of orientation can have devastating results even in the most apparently benign of environments once the ability to seek help is removed.
      • Providers need to consider the benefits of Accreditation and market events with an emphasis on personal safety.
      • That the organisation updates the written material delivered to co-ordinators to specify that participants must obtain written pre-approval for each event, planned on identified dates, and that staff must keep records of such pre- approval. In circumstances where an expedition is cancelled after pre-approval, records should be kept of the pre-approval and reasons for cancellation.
      Training & educationReview and update course content
      • National accredited courses (*delivered by multiple organisations as Provide First Aid - HLTAID003) need to consider revising content and training.


      Knowledge of risks
      • Pre-event information should be updated to reflect the dangers of heat stroke, heat exhaustion and dehydration and ways in which to manage these conditions. Participants should be thoroughly briefed on these dangers prior to event and reminded of them throughout.
      • Parents/guardians should be fully advised of the risks of the event prior to signing a consent form.
      • Organisations need to be mindful of the fact people inexperienced in remote conditions frequently have no concept of their own safety.
      • That the organisation review its educational material (on-line services, signage, literature and use of external media) to determine whether it can offer further assistance to educate the public about the importance of carrying sufficient quantities of water and adequately planning overnight walks.
      • That organisation devise a public notice and take steps to ensure that copies of the notice are placed on public notice boards where there is potential for people to become stranded in remote areas.
      • That organisations who service remote communities liaise with community leaders with a view to arranging for the training of community members about survival when lost or stranded.


      Plan ahead
      • Educate participants on the importance of contacting appropriate local authorities to determine the:
        1) availability of water on planned walking routes;
        2) availability of schemes that provide for the registration of trips with local authorities; and
        3) importance of utilising such schemes;
      • In organised activities, participants should obtain written pre-approval for each expedition, planned on identified dates


      Understand first aid
      • That organiser adopt immediate procedures to provide more accurate guidelines for heat stress management during such activities. Consider the resources offered by Sports Medicine Australia which relate to sporting activities in times of high heat and humidity.
      • That the organisation conduct a review of its literature relating to advice to staff and participants on water consumption during events
      • That a working party (five organisations named) be established to review the structure, operation, management and training for triple 0 emergency call centres, with attention given to (several organisational and equipment issues identified)
      EquipmentProvision of safety equipment
      • Staff should make use of equipment to check on current weather forecasts prior to each day's activities and periodically throughout the day and amend the activities accordingly.
      • The value of one candidate in any walking group carrying a Personal Locator Beacon (PLB) where those devices are available from Police or the National Parks and Wildlife Service
      • That the organisation review its capacity to educate the public as to the availability of PLB's
      • That a review be conducted to determine whether the organisation provides sufficient assistance to members of the public in relation to safe water consumption on walks and the availability of Personal Locator Beacons (PLB's). Where necessary, funding should be allocated to ensure that the organisation is able to deliver the appropriate education campaign and update information sources
      BehavioursReschedule events
      • That the *organiser consider holding their event during periods of lower/milder heat and not during peak summer conditions.
      • Rescheduling of events is a well-supported mitigation strategy. There are several known challenges in re-scheduling particularly in regard to planning ahead (avoiding last minute changes) and venue availability.
      Temperature or weather descriptors were available for 31 cases (Supplementary Table 4). Twelve cases were noted to occur in temperatures that exceeded 40 °C and seven cases were 35–39°. Twenty four cases made note of a hot temperature or extreme heat and five specified high humidity.

      4. Discussion

      This is the first study to present national population-based data on heat-related deaths linked to sport and recreation activity in Australia. The results confirm that while such deaths are rare, they occur with enough regularity to warrant renewed attention toward their prevention. Three key findings of our study are highlighted: population targets; hiking in the heat; and sign/symptom awareness. Firstly, we found two distinct populations at risk. One is young-to-middle aged men, between the ages of 15–45 years, and the second is international visitors. Recognising these two distinct groups is crucial to targeting information that is most relevant and accessible for them. Secondly, most fatalities occurred during hiking on days invariably described as being extremely hot with high humidity. We recommend the development of clear and simple messaging aligned with the view that ‘hiking on days of extreme heat is strongly discouraged.’ Third and finally, exertional heat illness signs and symptoms should be well-known among active populations as delays can be fatal. Three quarters of cases in this series died at the location of the incident where they were active. Where known, the time between the first symptoms being identified and death occurring was frequently more than 5 h. Rapid recognition and calling for emergency assistance as soon as a case is suspected is crucial to survival.
      Recommendations targeted to individuals or populations were focused around planning ahead and taking personal responsibility. Specific strategies included ensuring water would be available along the chosen trail or carrying a sufficient quantity for the activity, as well as registering trips with local authorities, including the planned route and timings. Such strategies rely on individuals knowing, and doing, the right thing. Work arising from the Australian Understanding and Preventing Led Outdoor Accidents Data System (UPLOADS) has shown that event contributory factors are often apportioned to those within an individual's control while factors aimed at a broader system level are missed, despite their potential for stronger influence on prevention.
      • McLean S.
      • Finch C.F.
      • Goode N.
      • et al.
      Applying a systems thinking lens to injury causation in the outdoors: evidence collected during 3 years of the understanding and preventing led outdoor accidents data system.
      The recommendations targeted at organisations in this series were focused on content of first aid training, having strong knowledge of heat risks and how to manage them, rescheduling of events, providing equipment (including personal locator beacons) and communicating in multiple formats. Specifically, national accredited first aid courses were encouraged to consider revising content and training and aligning with the resources available from Sports Medicine Australia.
      • Gamage P.J.
      • Finch C.F.
      • Fortington L.V.
      Document analysis of exertional heat illness policies and guidelines published by sports organisations in Victoria, Australia.
      There are two important implications of these recommendations. Firstly, most cases were not in an environment where these specific organisational strategies would easily reach individuals, thereby limiting their impact. Secondly, if relying on guidelines published by Sports Medicine Australia, it is critical that resourcing allows them to be regularly revised and updated considering new research evidence.
      Australia has a large and varied landscape with differing climate regions that change throughout the year. Some regions are uniquely hot or humid throughout the year, such as the Northern Territory, where investigation of environmental deaths, inclusive of heat fatalities has been previously reported.
      • Tiemensma M.
      Environmental deaths in the Northern Territory of Australia, 2003–2018.
      Other areas present risky conditions periodically, such as the heatwaves experienced throughout the Summer months in the Southern States (e.g. Victoria, South Australia). Thus, the region and timing of deaths were important to consider in this study. Almost half of the cases occurred in a state that was not the home residence of the deceased emphasising the importance of knowing, and being suited to, the local conditions and emergency services. Cases occurred throughout the year, though as expected, notably more were in the Summer months. Safety messaging and reminders should be considered in the pre-summer period, as occurs with the timing of water safety messages.
      • Casten M.
      • Crawford G.
      • Jancey J.
      • et al.
      ‘Keep watch’ around water: short-term impact of a Western Australian population-wide television commercial.
      Twenty-seven fatalities were linked to hiking activities (note - we had also excluded several cases of walking where the intent of activity was not specifically for fitness or competition.) Participation data for bush walking is presented in a 2019 SportAus report from the Ausplay survey.
      • SportAus. Bush Walking
      State of Play Report: Driving Participation & Engagement.
      In Australia, bush walking and hiking are often used interchangeably as terms representing physical activity along a nature trail. SportAus reported that bush walking is popular with males and females across all age groups and the top participation reasons were consistently rated as fun/enjoyment, to be outdoors/to enjoy nature and for physical health and fitness. Thus, the high number of fatalities is a disappointing outcome when considering the non-competitive nature and ease of avoidance of the activity, where conditions are unsuitable. Previous studies have considered peoples' behaviours in National Parks, exploring, for example, their reasons for walking off trail or for leaving rubbish behind.
      • Goh E.
      Breaking the rules to venture off-trail at national parks: exploring salient beliefs through a planned behaviour approach.
      ,
      • Goh E.
      Walking off-trail in national parks: monkey see monkey do.
      Similar study designs addressing why choices are made to continue activity in risky conditions would be valuable in developing prevention strategies. We suggest that a reasonable proportion of people might not view hiking as a high risk activity, as described in a study of safety messaging in parks where incidents that occur are often attributed to the “visitors' failure to understand the seriousness of risk in unfamiliar and unpredictable natural environments.”,
      • Saunders R.
      • Weiler B.
      • Scherrer P.
      • et al.
      Best practice principles for communicating safety messages in national parks.
      p.132. Only a small proportion (11%) of those surveyed for the Ausplay study indicated they are involved in an organised version of bush walking.
      • SportAus. Bush Walking
      State of Play Report: Driving Participation & Engagement.
      Thus, community-driven strategies that are able to reach individual, recreational hikers are needed. Ideally this would not only involve outdoor activity providers but have cooperation from wider agencies, such as parks and recreation. Commercial organisations might also play an important role through their potential reach and online social media presence.
      Successful prevention measures in US sport settings have been developed from knowledge derived from long term surveillance
      • Kucera K.L.
      • Klossner D.
      • Colgate B.
      • et al.
      Annual survey of football injury research 1931–2018.
      and research trials.
      • Yeargin S.W.
      • Casa D.J.
      • Armstrong L.E.
      • et al.
      Heat acclimatization and hydration status of American football players during initial summer workouts.
      Findings are subsequently shared through positions statements,
      • Casa D.J.
      • DeMartini J.K.
      • Bergeron M.F.
      • et al.
      National Athletic Trainers’ Association position statement: exertional heat illnesses.
      guidelines
      • Casa D.J.
      • Csillan D.
      • Armstrong L.E.
      • et al.
      Preseason heat-acclimatization guidelines for secondary school athletics.
      ,
      • Adams W.M.
      • Casa D.J.
      • Drezner J.A.
      Sport safety policy changes: saving lives and protecting athletes.
      and sport specific resources. A positive finding from our results was the low number of cases in organised sport settings. It is probable that the available team and bystanders supported the awareness of a problem and transport to hospital, which was not the case for the recreation deaths. The success of the efforts from organised sports should be viewed as a positive for recreational sport participants and industry to aim for.
      Our results are limited to the 38 fatalities that were identifiable within the NCIS database. We consider that this is strong justification for a rethink on prevention strategies particularly given that for every exertional heat fatality there are likely to be several near miss cases. At present, we do not have suitable data for a fatality-to -near-miss ratio within Australia or directly related to sport,
      • Gamage P.J.
      • Fortington L.V.
      • Finch C.F.
      Epidemiology of exertional heat illnesses in organised sports: a systematic review.
      ,
      • McMahon S.
      • Gamage P.J.
      • Fortington L.V.
      Sports related heat injury in Victoria, Australia; an analysis of 11 years of hospital admission and emergency department data.
      though evidence from other studies suggest the near miss numbers could be substantial; a 5-year study focused on heat illness in the Grand Canyon, USA, identified 6 deaths and 474 non-fatal heat illness.
      • Noe C.D.R.R.S.
      • Choudhary E.
      • Cheng-Dobson L.J.
      • et al.
      Exertional heat-related illnesses at the Grand Canyon National Park, 2004–2009.
      Noted in the introduction is a lack of agreed and consistent terminology for heat morbidity in active populations.
      • O'Connor F.G.
      • Casa D.J.
      Exertional heat illness in adolescents and adults: epidemiology, thermoregulation, risk factors, and diagnosis.
      Consistent with a previous study of environmental-linked deaths in the Northern Territory,
      • Tiemensma M.
      Environmental deaths in the Northern Territory of Australia, 2003–2018.
      several variations for the cause of death were noted in different parts of the coronial files. For some cases, specific and clear terminology, linked to ICD-codes was available (e.g. X308 — Exposure to excessive natural heat and T679 — Effect of heat and light). For other cases, the diagnosis was more descriptive using variations of: Heat stroke; Heat-stroke; Heatstroke; Heat exhaustion; Heat stress; Hyperthermia; Dehydration; and others. Options to support specific diagnoses (e.g. sodium levels for hyponatraemia
      • Hew-Butler T.
      • Loi V.
      • Pani A.
      • et al.
      Exercise-associated hyponatremia: 2017 update.
      ) were not possible as our case identification was reliant on administrative data.
      The inclusion of cases required multiple search queries using a combination of diagnostic codes and free text searches. All potentially relevant files were reviewed in full. Both the cause of death and the activity at time of death being subject to discussion for inclusion. Similarly, with activity at time of death, most cases were clearly specified as ‘sport and recreation during leisure time.’ The question of ‘exertion’ was critical to inclusion in cases where the coded data was unclear and therefore our decisions were reliant on written diagnoses and reporting. We chose a conservative inclusion of cases wherein the deceased was clearly active with intent of fitness or competition. We noted several cases in young populations engaged in active play where exertion likely contributed to the outcome. Similarly, we noted cases in older populations where exertion was also likely to have contributed to the outcome while engaged in tasks at home. In both situations, these cases were determined as not being active for fitness or competition and were excluded. This was primarily decided because such cases will require a different prevention approach from those cases that were ultimately included.

      5. Conclusion

      The heat and extreme conditions in Australia are generally respected and there are several ways in which awareness of extreme days are promoted to reduce morbidity and mortality. Despite this, there were 38 preventable deaths identified in this series. Most cases were participating in outdoor recreation, such as hiking, on a day of high temperature. Specific consideration of how to reach young-to-middle aged men and international visitors with safety messaging is critical. Messaging must identify firstly that heat kills and secondly, that medical care should be rapidly accessed at first suspicion of symptoms/signs.

      Funding information

      Funding was received from the Victorian State Government for conduct of the project from which this study is derived.

      Declaration of interest

      Author LVF is an Associate Editor with the Journal of Science and Medicine in Sport. There are no other conflicts of interest declared.

      Confirmation of ethical compliance

      This study was approved by the Justice Human Research Ethics Committee CF/19/24669 and Western Australia Coronial Ethics Committee.

      Acknowledgements

      We acknowledge the Department of Justice and Community Safety (source organisation of the data), and the National Coronial Information System (database source).

      Appendix A. Supplementary data

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