Application of evidence-based recommendations for heat acclimation: Individual and team sport perspectives

Abstract

Heat acclimation or acclimatization (HA) occurs with repeated exposure to heat inducing adaptations that enhance thermoregulatory mechanisms and heat tolerance leading to improved exercise performance in warm-to-hot conditions. HA is an essential heat safety and performance enhancement strategy in preparation for competitions in warm-to-hot conditions for both individual and team sports. Yet, some data indicate HA is an underutilized pre-competition intervention in athletes despite the well-known benefits; possibly due to a lack of practical information provided to athletes and coaches. Therefore, the aim of this review is to provide actionable evidence-based implementation strategies and protocols to induce and sustain HA. We propose the following suggestions to circumvent potential implementation barriers: 1) incorporate multiple induction methods during the initial acclimation period, 2) complete HA 1-3 weeks before competition in the heat to avoid training and logistical conflicts during the taper period, and 3) minimize adaptation decay through intermittent exercise-heat exposure or re-acclimating immediately prior to competition with 2-4 consecutive days of exercise-heat training. Use of these strategies may be desirable or necessary to optimize HA induction and retention around existing training or logistical requirements.

Heat alleviation strategies for athletic performance: A review and practitioner guidelines

“…That said, HA will require specialist facilities, with training often having to be completed on a stationary ergometer (i.e. running, cycling or rowing) [15], though "circuit/strength training" activity can be implemented [91]. The use of ergometry may be considered as a limitation, but this is arguably offset by the ability to individualize the protocol and regulate stimuli more precisely.…”

“…The time of day for HA may be of relevance depending on the type of intervention. Whilst fixedintensity and isothermic HA interventions generally elicit similar magnitudes of adaptation when performed at the same time-of-day [50,105], isothermic HA has been proposed as superior/more efficient given they induce equal adaptations for a reduced workload [15]. It is in this regard that the time-ofday may greatly impact the exercise requirements to achieve the endogenous stimuli for adaptation (the change in T CORE ) in an isothermic protocol, given typical fluctuations in circadian rhythm and thus, starting T CORE .…”

“…Heat adaptations can be induced rapidly (e.g. <5 d [14]), and whilst decay occurs over time (e.g.~1-3 wk), expedient reinduction is possible [15,16]. HA can be implemented in different ways i.e.…”

“…In keeping with previous work [15,22,23], this review is written with the practitioner in mind and with athlete-centric considerations at the forefront of the content. To that end, the experiences of practitioners working with elite athletes have informed the perspectives within this review.…”

Intermittent sprint performance in the heat is not altered by augmenting thermal perception via L-Menthol or Capsaicin mouth rinses

“…team sport players, should preference either pre cooling, or mid (per) cooling interventions as an acute ergogenic aid (Castle et al 2006;Luomala et al 2012;Sunderland et al 2015), or a heat acclimation strategy e.g. the preferable isothermic approach (Racinais et al 2015a;Pryor et al 2018), to induce enhanced physiological responses to intermittent sprinting as part of a chronic intervention (Sunderland et al 2008;Castle et al 2011) in a manner that minimises training disruption (Gibson et al 2015).…”