Topical and Ingested Cooling Methodologies for Endurance Exercise Performance in the Heat.

Russ Best,Florence Riera,Stephen Payton,Iain Spears,Nicolas Berger

doi:10.3390/sports6010011

Abstract

This systematic review and meta-analysis aimed to assess studies which have investigated cooling methodologies, their timing and effects, on endurance exercise performance in trained athletes (Category 3; VO2max ≥ 55 mL·kg·min−1) in hot environmental conditions (≥28 °C). Meta-analyses were performed to quantify the effects of timings and methods of application, with a narrative review of the evidence also provided. A computer-assisted database search was performed for articles investigating the effects of cooling on endurance performance and accompanying physiological and perceptual responses. A total of 4129 results were screened by title, abstract, and full text, resulting in 10 articles being included for subsequent analyses. A total of 101 participants and 310 observations from 10 studies measuring the effects of differing cooling strategies on endurance exercise performance and accompanying physiological and perceptual responses were included. With respect to time trial performance, cooling was shown to result in small beneficial effects when applied before and throughout the exercise bout (Effect Size: −0.44; −0.69 to −0.18), especially when ingested (−0.39; −0.60 to −0.18). Current evidence suggests that whilst other strategies ameliorate physiological or perceptual responses throughout endurance exercise in hot conditions, ingesting cooling aids before and during exercise provides a small benefit, which is of practical significance to athletes’ time trial performance.

Highlights

Heat exposure imposes perceptual and physiological demands on athletes that can be attenuated by interventions; the precise timing and best method of administration for these remain unclear
Topical (−0.50; −1.03 to 0.04) and ingested (−0.41; −0.61 to −0.20) methodologies induced small beneficial effects upon rating of perceived exertion (RPE), with trivial effects found when combined strategies were applied (−0.13; −0.53 to 0.27). This meta-analysis aimed to assess the effects of practical precooling and percooling strategies applied to trained endurance athletes exercising in hot environmental conditions
We found combining topical and ingested cooling methods to only have a trivial effect upon time trial performance with a broad confidence interval (−0.07; −0.44 to 0.29), supported by an expectedly trivial change in power output (0.02; −0.39 to 0.44)

Summary

Introduction

Heat exposure imposes perceptual and physiological demands on athletes that can be attenuated by interventions; the precise timing and best method of administration for these remain unclear. Cooling strategies applied before (precooling) and during (percooling) exercise have been shown to ameliorate deleterious symptoms experienced whilst exercising in the heat [1] Strategies to attenuate these factors are of importance given the increasingly global nature of elite endurance sports, and the consequent scheduling demands placed upon athletes who often arrive at events with little time for heat-acclimatisation. Subjective measures of athlete wellbeing/fatigue have been shown to be more reliable and sensitive than objective indices in predicting performance, better reflecting acute and chronic training stresses [7]. These findings highlight the importance of how an athlete feels in determining performance outcomes. Cooling methodologies that display no physiological effect but improve psychological condition may still be of value to the athlete with respect to performance

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Discussion

Conclusion