Roundtable on Preseason Heat Safety in Secondary School Athletics: Heat Acclimatization

Abstract

Objective To provide best-practice recommendations for developing and implementing heat-acclimatization strategies in secondary school athletics. Data Sources An extensive literature review on topics related to heat acclimatization and heat acclimation was conducted by a group of content experts. Using the Delphi method, action-oriented recommendations were developed. Conclusions A period of heat acclimatization consisting of ≥14 consecutive days should be implemented at the start of fall preseason training or practices for all secondary school athletes to mitigate the risk of exertional heat illness. The heat-acclimatization guidelines should outline specific actions for secondary school athletics personnel to use, including the duration of training, the number of training sessions permitted per day, and adequate rest periods in a cool environment. Further, these guidelines should include sport-specific and athlete-specific recommendations, such as phasing in protective equipment and reintroducing heat acclimatization after periods of inactivity. Heat-acclimatization guidelines should be clearly detailed in the secondary school's policy and procedures manual and disseminated to all stakeholders. Heat-acclimatization guidelines, when used in conjunction with current best practices surrounding the prevention, management, and care of secondary school student-athletes with exertional heat stroke, will optimize their health and safety.

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

“…15 93 For summer sports where the potential for sweat evaporation may be reduced by protective equipment, the heat stress risk of non-heat acclimated athletes can be managed by permitting a progressive period of heat adaptation with minimal equipment coverage over several days before full protective equipment ensembles are worn. 74 The common practice of some sports such as using large 'bibs' (ie, sleeveless shirts with numbers and logos for identifying and commercial purposes) may also have to be adapted to provide the athletes with garments of appropriate fabric, size and fitting so as not to impair sweat evaporation. Despite our better understanding of sweat physiology 149 and clothing requirements, 150 it remains unclear how different commercially available clothing should be selected depending on the prevailing level of heat stress (eg, tropical vs desert), skin colour, previous exposure/tan and activity.…”

“…Research studies have consistently reported that performance in the heat increases after days/weeks of training in the heat,71 or that athletes are less likely to suffer a heat-related medical event when they are acclimated to hot ambient conditions when required to do intense exercise 65 72. The physiological and performance benefits of heat acclimation have been extensively covered in numerous recent narrative reviews,67 73 meta-analyses,68 consensus statements,7 15 Delphi consensus74 and practical recommendations 70…”

“…It is therefore recommended that clothing should impair sweat evaporation as little as possible, and the exposed skin area available for evaporative heat loss in athletes is maximised 15 93. For summer sports where the potential for sweat evaporation may be reduced by protective equipment, the heat stress risk of non-heat acclimated athletes can be managed by permitting a progressive period of heat adaptation with minimal equipment coverage over several days before full protective equipment ensembles are worn 74. The common practice of some sports such as using large ‘bibs’ (ie, sleeveless shirts with numbers and logos for identifying and commercial purposes) may also have to be adapted to provide the athletes with garments of appropriate fabric, size and fitting so as not to impair sweat evaporation.…”

Exertional heat stroke in sport and the military: epidemiology and mitigation

“…Several strategies to mitigate the impact of environmental heat stress exist in both athletic and military settings, including heat acclimation, ensuring adequate hydration and mandated work‐to‐rest ratios (Army, 2022 ; McCubbin et al., 2020 ; Périard et al., 2021 ). A number of organisations have also published guidance for the prevention of heat‐related illness and EHS (Adams et al., 2021 ; Casa et al., 2015 ; Roberts et al., 2021 ) and a wide variety of risk factors have been identified (Bouchama et al., 2022 ; DeGroot et al., 2015 ; Leon & Kenefick, 2011 ). In this review, we examine the epidemiology of EHS, the most common risk factors, and policies designed to mitigate risk in sport and military settings.…”

A Review of Elite Athlete Evidence-Based Knowledge and Preparation for Competing in the Heat

“…Elite endurance training provides a health protective effect against EHS. For example, even temperate-based elite endurance training induces a partially heat acclimated phenotype [3,7,35,102] whilst elite endurance athletes who are heat acclimated/acclimatised can tolerate a Tc ≥ 41 °C without succumbing to EHS (i.e., no alteration in mental status [80,84,97]). Across various competition levels, intermittent sport athletes (386 individuals across 34 studies) have been observed to reach a peak Tc of 38.5 °C to 39.5 °C (24 of 34 studies included in a recent systematic review) and ≥ 39.5 °C (6 out of 34 studies [38]).…”