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Extreme Physiology & Medicine

Open Access

Investigating the lower ambient temperature limit for pre-cooling to be beneficial for athletic performance

  • Iris Broekhuijzen1Email author,
  • Simon Hodder1,
  • Maarten Hupperets1 and
  • George Havenith1
Extreme Physiology & Medicine20154(Suppl 1):A2

Published: 14 September 2015


Skin TemperatureEnvironmental TemperatureThermal ComfortTime TrialThermal Sensation


When exercising in the heat, performance is deteriorated. It has been shown that pre-cooling can counteract this deterioration in the heat [1], but it is unclear what the effects of pre-cooling on performance are in temperate environments. Thus, the current study was performed to see if there is any difference in performance with pre-cooling at 24 °C and 27 °C, and thus if there is a threshold in environmental temperature above which pre-cooling becomes beneficial to performance. We hypothesised pre-cooling to enhance performance at both environmental temperatures.


Nine healthy males (mean (SD) age 24.2 (7.2) years; VO2,max 60.6 (6.2) participated in the study. Six participants performed 4 experimental trials: CON27 (control, 27 °C), COOL27 (pre-cooling, 27 °C), CON24 (control, 24 °C) & COOL24 (pre-cooling, 24 °C). Three participants only performed CON27 & COOL27. Pre-cooling was applied for 30 minutes and during the warm-up before a cycling time trial. Participants were cooled using a cooling vest and sleeves made of a combination of a mesh fabric and pockets filled with hydrophilic silica gel, which was soaked and frozen overnight. 30 minutes of baseline measurements in room temperature (23.3 (0.7) °C) were taken, followed by 39 minutes of pre-cooling in testing climate of which the last 9 minutes participants were warming up. Performance was measured using a time trial equivalent to cycling for one hour at 75 % VO2,max. Mean skin temperature (Tskin) was measured throughout the trial using 8 iButtons [2] and core temperature was measured using a radio pill (Tcore). Body temperature (Tbody) was subsequently calculated using the calculation from Hardy et al. [3]. Thermal sensation (-10 to +10, extremely cold to extremely hot), thermal comfort (0 to 7, comfortable to extremely uncomfortable) and rating of perceived exertion (RPE; [4]) were assessed at 20% intervals of the time trial.


Results show a significant performance improvement at 27 °C (p = 0.036 (one-tailed)), but no significant differences are seen at 24 °C (p = 0.325 (one-tailed)). This was strengthened by the Hopkins approach [5], which showed a 97% or a very likely chance of an improvement in performance at 27 °C following pre-cooling. Pre-cooling lowered both Tskin (p < 0.005) and Tbody (p < 0.05), but not Tcore. Sweat rate was significantly lowered following pre-cooling at 27 °C (0.67 (0.11) vs. 0.61 (0.13); p < 0.05), but not at 24 °C (p = 0.075). Furthermore, thermal sensation was lower (i.e. cooler) following pre-cooling (27: 1.6 (1.4) vs. -4.0 (1.41), 24: -0.33 (0.94) vs. -4.33 (1.25); p < 0.05) and thermal discomfort was increased (27: 1.2 (0.4) vs. 2.8 (0.75), 24: 1.0 (0.0) vs. 3.5 (1.2); p < 0.05) following pre-cooling.


Our results indicate that pre-cooling improves performance in 27 °C, but not in 24 °C and thus that the threshold in environmental temperature for pre-cooling using the tested cooling vest and sleeves to become beneficial for cycling time trial performance appears to be above 24 °C.

Authors’ Affiliations

Environmental Ergonomics Research Centre, Loughborough University, UK


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© Broekhuijzen et al.; 2015

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.