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

International competition inevitably presents logistical challenges for athletes. Events such as the Tokyo 2020 Olympic Games require further consideration given historical climate data suggest athletes will experience significant heat stress. Given the expected climate, athletes face major challenges to health and performance. With this in mind, heat alleviation strategies should be a fundamental consideration. This review provides a focused perspective of the relevant literature describing how practitioners can structure male and female athlete preparations for performance in hot, humid conditions. Whilst scientific literature commonly describes experimental work, with a primary focus on maximizing magnitudes of adaptive responses, this may sacrifice ecological validity, particularly for athletes whom must balance logistical considerations aligned with integrating environmental preparation around training, tapering and travel plans. Additionally, opportunities for sophisticated interventions may not be possible in the constrained environment of the athlete village or event arenas. This review therefore takes knowledge gained from robust experimental work, interprets it and provides direction on how practitioners/coaches can optimize their athletes' heat alleviation strategies. This review identifies two distinct heat alleviation themes that should be considered to form an individualized strategy for the athlete to enhance thermoregulatory/performance physiology. First, chronic heat alleviation techniques are outlined, these describe interventions such as heat acclimation, which are implemented pre, during and post-training to prepare for the increased heat stress. Second, acute heat alleviation techniques that are implemented immediately prior to, and sometimes during the event are discussed. Abbreviations: CWI: Cold water immersion; HA: Heat acclimation; HR: Heart rate; HSP: Heat shock protein; HWI: Hot water immersion; LTHA: Long-term heat acclimation; MTHA: Medium-term heat acclimation; ODHA: Once-daily heat acclimation; RH: Relative humidity; RPE: Rating of perceived exertion; STHA: Short-term heat acclimation; TCORE: Core temperature; TDHA: Twice-daily heat acclimation; TS: Thermal sensation; TSKIN: Skin temperature; V̇O2max: Maximal oxygen uptake; WGBT: Wet bulb globe temperature.

Neck Cooling Improves Table Tennis Performance amongst Young National Level Players

This study aimed to examine the effects of neck cooling on table tennis performance. Eight young, National level, male table tennis players (age 16 ± 2 years, height 1.77 ± 0.08 m, body mass 67.54 ± 10.66 kg) were recruited. Participants attended four testing sessions separated by a week. Session one determined fitness levels, and session two was a familiarisation trial. The final two sessions involved completing the table tennis-specific protocol either with (ICE) or without (CON) neck cooling for 1 min before each exercise period (bout: 80⁻90 shots), which represented an individual game. The exercise protocol required completing three bouts to represent a match, each simulating a different skill (forehand, backhand, alternate forehand and backhand), against a mechanical ball thrower. Performance was measured by the number of balls hitting two pre-determined targets. Heart rate, ratings of perceived exertion (RPE), and thermal sensation (TS) were measured. Total performance scores (shots on target) were significantly greater during ICE (136 ± 26), compared to CON (120 ± 25; p = 0.006) with a 15 (±12)% improvement. Effects for time (p < 0.05) but not condition (p > 0.05) were found for RPE and all other physiological variables. TS significantly decreased with cooling throughout the protocol (p = 0.03). Neck cooling appears to be beneficial for table tennis performance by lowering thermal sensation.

Running performance in the heat is improved by similar magnitude with pre-exercise cold-water immersion and mid-exercise facial water spray

This investigation compared the effects of external pre-cooling and mid-exercise cooling methods on running time trial performance and associated physiological responses. Nine trained male runners completed familiarisation and three randomised 5 km running time trials on a non-motorised treadmill in the heat (33°C). The trials included pre-cooling by cold-water immersion (CWI), mid-exercise cooling by intermittent facial water spray (SPRAY), and a control of no cooling (CON). Temperature, cardiorespiratory, muscular activation, and perceptual responses were measured as well as blood concentrations of lactate and prolactin. Performance time was significantly faster with CWI (24.5 ± 2.8 min; P = 0.01) and SPRAY (24.6 ± 3.3 min; P = 0.01) compared to CON (25.2 ± 3.2 min). Both cooling strategies significantly (P < 0.05) reduced forehead temperatures and thermal sensation, and increased muscle activation. Only pre-cooling significantly lowered rectal temperature both pre-exercise (by 0.5 ± 0.3°C; P < 0.01) and throughout exercise, and reduced sweat rate (P < 0.05). Both cooling strategies improved performance by a similar magnitude, and are ergogenic for athletes. The observed physiological changes suggest some involvement of central and psychophysiological mechanisms of performance improvement.