Effect of regular precooling on adaptation to training in the heat

Document Type

Journal Article

Publication Title

European Journal of Applied Physiology




Centre for Exercise and Sports Science Research / School of Medical and Health Sciences




Edith Cowan University, ECU


Choo, H. C., Peiffer, J. J., Pang, J. W., Tan, F. H., Aziz, A. R., Ihsan, M., ... Abbiss, C. R. (2020). Effect of regular precooling on adaptation to training in the heat. European Journal of Applied Physiology, 120, 1143-1154. https://doi.org/10.1007/s00421-020-04353-1


Purpose: This study investigated whether regular precooling would help to maintain day-to-day training intensity and improve 20-km cycling time trial (TT) performed in the heat. Twenty males cycled for 10 day × 60 min at perceived exertion equivalent to 15 in the heat (35 °C, 50% relative humidity), preceded by no cooling (CON, n = 10) or 30-min water immersion at 22 °C (PRECOOL, n = 10). Methods: 19 participants (n = 9 and 10 for CON and PRECOOL, respectively) completed heat stress tests (25-min at 60% V ˙ O 2peak and 20-km TT) before and after heat acclimation. Results: Changes in mean power output (∆MPO, P = 0.024) and heart rate (∆HR, P = 0.029) during heat acclimation were lower for CON (∆MPO − 2.6 ± 8.1%, ∆HR − 7 ± 7 bpm), compared with PRECOOL (∆MPO + 2.9 ± 6.6%, ∆HR − 1 ± 8 bpm). HR during constant-paced cycling was decreased from the pre-acclimation test in both groups (P < 0.001). Only PRECOOL demonstrated lower rectal temperature (Tre) during constant-paced cycling (P = 0.002) and lower Tre threshold for sweating (P = 0.042). However, skin perfusion and total sweat output did not change in either CON or PRECOOL (all P > 0.05). MPO (P = 0.016) and finish time (P = 0.013) for the 20-km TT were improved in PRECOOL but did not change in CON (P = 0.052 for MPO, P = 0.140 for finish time). Conclusion: Precooling maintains day-to-day training intensity and does not appear to attenuate adaptation to training in the heat. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.



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