Discussion
There has been an increasing concern shared by sports organisations on weather change and global warming, and its effects towards developing EHI. In order to disseminate information on EHI risk mitigation to their communities, sports organisations need to understand the latest evidence related to EHI in sports. The present study identified EHI-related documents published by sports organisations in Victoria and analysed their content by rating them against an extract of current international recommendations.7–9 Findings highlighted the gaps and limitations in existing Victorian sports organisations’ official EHI documentation. Most documents focused on three main areas: (1) weather-related parameters as major risks, primarily referring to ambient temperature (n=22 documents; 84% of all identified documents); (2) the importance of hydration in preventing EHI (n=20 documents; 80% of all identified documents); and (3) event modification and cancellation strategies (n=22; 88% of all identified documents). Most EHI documents were not comprehensive enough to provide current best evidence and, given their age, they may need reviewing. Importantly, this study found that there is a need for EHI policies to be updated in line with emerging scientific evidence.
The recent international consensus recommendations mainly focused on three main preventive measures for EHI: heat acclimatisation, hydration and cooling strategies.9 It is recommended for athletes to undertake exercise in a euhydrated state and minimise body water deficits through proper rehydration during exercise.9 In the present analysis, most documents provided a good account on hydration in preventing EHI, detailing the type, volume and timing of fluid intake. This most likely reflects the fact that ‘hydration’ has long been a general topic in sports science, for preventing of EHI and for improving performance22 and cognitive functions.23 Nonetheless, the most suitable fluid intake strategies and recommendations should be made based on the playing context and availability of additional resources such as medical trained personnel.24 For example, elite-level athletes can benefit from having a ‘programmed drinking’ strategy (eg, calculating specific fluid volumes per kilogram body mass).25 On the other hand, ‘ad libitum drinking’ (consumption of fluid to thirst) can be a suitable recommendation for community sporting context where resources may not be available for advance fluid intake strategies.26
In contrast to the hydration issue, which was well covered in the documents, there was far less emphasis on heat acclimatisation and cooling strategies. At the community-level sport participation, simple cooling strategies such as fanning air, application of cold towels, ingestion of cold fluids or ice slurry and resting in shade or access to air-conditioned rooms during the breaks can be effective in reducing the risk of EHI.9 For individuals with suspected heat stroke, immediate whole body cooling is strongly recommended before transporting to a hospital, in order to minimise morbidity and mortality.7–9 Current evidence shows the importance of structured heat acclimatisation sessions for athletes (ideally for 2 weeks using a comparable degree of heat stress as the target competition) to gain complete physiological adaptations and maximum benefits.9 These recommendations were not addressed in most documents included in this study. Within the context of community sport participation, it is difficult to consider the role of heat acclimation. For elite athletes, well-structured heat acclimatisation strategies can be implemented with the resources available at elite level. Therefore, recommendations in policy documents should be tailored to suit the playing context and availability of resources. If possible, heat acclimatisation programmes can be incorporated into participants’ training by coaching staff, when they expect to compete in hot environments.7–9 Where not feasible, players and staff should be additionally mindful of risk.
Defining and recognising early forms of EHI are discussed in recent literature.27 Clarity on EHI definitions is important for accurate diagnosis of different forms of EHI and recognising their severity. The topic areas related to categorising and defining different EHI conditions, symptoms and signs to assist with early recognition, and first aid and treatment were not commonly addressed in the reviewed documents. A number of documents presented background information referring to more severe forms of EHI, such as heat exhaustion/heat stroke, but no mention of milder forms such as muscle cramps, heat rash and heat syncope was provided. Knowledge and awareness in these milder forms among sports participants, coaches and event organisers are important, especially as warning signs can be recognised through player monitoring, allowing treatment timely measures to be implemented.7 28 Therefore, the specific recommendations in the current documents could be expanded to ensure that they contain up-to-date information for recognising and managing early forms of EHI, thus avoiding progression to more severe and fatal forms such as heat stroke.2
Fewer than half of the documents included in this study presented a clear, evidence-informed strategy for event organisers to determine the level of risk when faced with a decision towards enacting event modification or cancellation measures. Where this strategy was in place, the event modification or cancellation decision was based mainly only on weather-related parameters and cut-off values, largely relying on ambient temperature and, to a lesser extent, WBGT. The weather data can be easily obtained through online resources such as the Bureau of Meteorology website (www.bom.gov.au), and therefore widely used by event organisers and serve as important indicators in making event modification/cancellation decisions. However, due to other multiple interacting factors that are associated with developing EHI, it is important not to rely solely on weather parameters (eg, WBGT, ambient temperature).9 For example, Cricket Australia has updated their heat policy in 2019 and introduced a Heat Stress Risk Index that includes two personal parameters (clothing, activity) relevant to cricket in addition to four environmental parameters (https://www.cricketaustralia.com.au/cricket/rules-and-regulations). Similarly, the National Rugby League (NRL) uses a checklist with many weather and non-weather parameters to gauge EHI risk (https://www.playrugbyleague.com/policies).
These weather indices do not account for metabolic heat production associated with exercise workload or individual characteristics of the athletes.9 The rate of metabolic heat production in the body during exercise is related to the intensity and duration of physical activity (workload)29 and therefore, a significant variation can be observed among different sports due to their different physical demands.30 In addition, some factors related to an individual participant, such as their body morphology,31 level of physical fitness31 and acclimatisation state, can also influence the development of EHI.32 Therefore, it would be useful for sports organisations to review their current guidelines and consider including non-weather-related factors where appropriate in making event modification or cancellation decisions.
The variability in the quality of recommendations, and complexity in providing evidence-based information to the community has been demonstrated in an earlier review.20 Findings of our study were consistent with this earlier review where hydration (fluid intake), weather parameters (heat limits) and event modification (precautionary interventions) were commonly presented as heat illness prevention themes.20 Other research into sports safety policy and guideline development in Australia has demonstrated both the advantages of such processes as well as the challenges that sports organisations face when developing and implementing local-level safety policies and practices.15 33 34 This reflects the current situation in Australia where a large number of resources for safety promotion in sports are available, but can often overlap in their focus and therein cause confusion.10 One previous effort against the proliferation of inconsistent information about EHI to sports organisations in Australia has been the publication of general guidelines by SMA.17–19 Of the 25 documents reviewed in this study, 11 had incorporated the SMA guidelines and refer to their website and related resources. However, very few of them had specifically adapted the SMA guidelines to match their sport and playing characteristics. While SMA guidelines provide a comprehensive account on EHI for Australia, and were disseminated along with the intent that sports organisations should adapt the information to match their specific sporting context and setting, limitations in these documents should be acknowledged (eg, particularly in making generalised recommendations based on weather parameters).35 Further, a recent analysis of the limitations in the content of SMA resources, concluded there is a compounded problem when sports organisations rely on those as their source of guidance. This puts a particular onus on sports medicine bodies to always make sure that their resources, developed with the intent that they will be used by sports bodies and other third parties, are kept fully up to date and are updated in a timely manner when new evidence is available. For example, the Australian NRL has used the SMA documents as a guide to develop their own risk grading system to recognise high-risk circumstances, and has recommended risk mitigation and preventive measures.
Limitations
The main purpose of using the three consensus recommendations was only to guide the content analysis of heat policy documents against updated guidelines. However, this does not assure the accuracy of the content in these threeo consensus documents, or the need for including the content in the current heat policies and guidelines. Similarly, the differences in content and quality of information observed in the different documents and sports do not merely suggest they are incomplete or incorrect. Further, the study does not suggest that policy documents related to heat should include all related details for every sport in a same manner. Rather, documents should include information relevant to the type of sports and playing context while including the most important evidence-based preventive and risk mitigation measures relevant to the context. With evolving scientific evidence, the best practice can change.
The content in the reviewed EHI documents was assessed against international position statements on EHI, although it is recognised that the Australian sports setting might have different requirements due to different sports and weather conditions. The primary document search was carried out by only one person, and secondary search was limited to the sports where no documents were found during the primary search. Only the first author was involved in summarising the best practice recommendations from the two position and consensus statements, and extracting and summarising information from selected sport-specific documents. A second author was involved only in reviewing the content in the sport-specific documents against the best practice recommendations. Due to these reasons, there could be potential bias in document selection, data retrieval and analysis. The sample of 22 sports included represents a large number of the major sports in Victoria, however, results may not be generalisable to other sports.