Physiological and Perceptual Effects of Cooling Trousers: A Crossover Pilot Study

Introduction
Cold-water immersion (CWI) is a commonly used recovery modality to positively affect subjective recovery parameters and reduce inflammatory reactions [1]. Because the use of CWI can be unpleasant and challenging, alternatives, such as cooling trousers by Icebein™, have been developed. Due to their novelty, there exists a lack of scientific research on the primary physiological and perceptual responses to these cooling trousers, which this pilot study seeks to examine.
Methods
Twelve healthy males (26±4.2 years old) volunteered to wear the Icebein™ cooling trousers for a duration of 20 min. with the water temperature set at 5ºC. Lower leg skin temperature (FLIR, A655, Kent, UK), skin perfusion of the m. quadriceps femoris vastus lateralis (moor VMS-LDF-1, Millwey, UK) and thermal perception (ISO 10551) were assessed at baseline, every 4 min. during the intervention (except skin temperature), and every 4 min. post-cooling up to 20 min. follow-up time. 
Results
Skin temperature significantly decreased from baseline to post-cooling (–12.4±5.63ºC, p<.001) and remained lower than baseline until the 20 min follow-up time (all: p<.001). Skin perfusion showed a significant decrease compared to baseline (p =0.038). Perfusion was decreased by 19.9±23.7% immediately post-cooling and by 22.1±26.4% at the end of the 20 min follow-up time. Wearing cooling trousers induced a significant perception of cold (p<.001) compared to baseline values.
Discussion & conclusion
The results show that the cooling trousers from Icebein™ elicit a significant skin-cooling reduction, decrease skin perfusion and induce a substantial perception of cold. These preliminary results demonstrate the physiological effects of this novel cooling strategy for potential performance recovery usage. Future studies should aim to directly compare the effects of cooling trousers and CWI with a larger sample size.