A Comparison of Mixed-Method Cooling Interventions on Preloaded Running Performance in the Heat

Abstract

Stevens, CJ, Bennett, KJM, Sculley, DV, Callister, R, Taylor, L, and Dascombe, BJ. A comparison of mixed-method cooling interventions on preloaded running performance in the heat. J Strength Cond Res 31(3): 620-629, 2017-The purpose of this investigation was to assess the effect of combining practical methods to cool the body on endurance running performance and physiology in the heat. Eleven trained male runners completed 4 randomized, preloaded running time trials (20 minutes at 70% V[Combining Dot Above]O2max and a 3 km time trial) on a nonmotorized treadmill in the heat (33° C). Trials consisted of precooling by combined cold-water immersion and ice slurry ingestion (PRE), midcooling by combined facial water spray and menthol mouth rinse (MID), a combination of all methods (ALL), and control (CON). Performance time was significantly faster in MID (13.7 ± 1.2 minutes; p < 0.01) and ALL (13.7 ± 1.4 minutes; p = 0.04) but not PRE (13.9 ± 1.4 minutes; p = 0.24) when compared with CON (14.2 ± 1.2 minutes). Precooling significantly reduced rectal temperature (initially by 0.5 ± 0.2° C), mean skin temperature, heart rate and sweat rate, and increased iEMG activity, whereas midcooling significantly increased expired air volume and respiratory exchange ratio compared with control. Significant decreases in forehead temperature, thermal sensation, and postexercise blood prolactin concentration were observed in all conditions compared with control. Performance was improved with midcooling, whereas precooling had little or no influence. Midcooling may have improved performance through an attenuated inhibitory psychophysiological and endocrine response to the heat.

The Development of a Menthol Solution for Use during Sport and Exercise

“…Menthol mouth swilling is considered a practical ergogenic strategy before and during exercise in hot environments [11,30] and has been used to improve performance during time trials [17,18] and time to exhaustion [16,31]. Perception of menthol mouth swill concentration may be highly individual in nature, with 200 gene variants of the receptor responsible for menthol detection (TRPM8 [32]).…”

“…All menthol-containing studies [9,10,[16][17][18][19]31] have employed a repeated exposure during the exercise bout-this is quantified via time or distance. Better understanding the time course of menthol mouth swilling responses, and the potential impact of concentrations upon these, would provide insight into possible limitations in application for menthol-containing strategies.…”

“…A more contemporary application of menthol has been that of an ergogenic aid which can be applied topically [15], used as a mouth swill [16][17][18] or ingested alongside ice slurry [9,10,19]. This use is fitting, with menthol shown to increase the drive to breathe [20], elevate ventilation [21] and attenuate thirst [13], along with eliciting sensations of coolness and freshness that may alleviate thermal symptoms during exercise [3].…”

Per-Cooling (Using Cooling Systems during Physical Exercise) Enhances Physical and Cognitive Performances in Hot Environments. A Narrative Review

“…This relative lack of interest in this area may be explained by issues regarding practicality (e.g., excess weight, skin irritation and sport regulations) [104]. Some recent studies suggested that the advantages gained from cooling during exercise may outweigh those of pre-cooling [105,106]. Cooling during exercise is named per-cooling ('per' is derived from the Latin word meaning 'during') [27].…”

The effect of ice slurry ingestion on body temperature and cycling performance in competitive athletes

“…Fewer studies have been conducted examining the effect of a combination of pre and mid-cooling (Stevens et al, 2017). Some studies have demonstrated improved endurance performance using the combination method (Tran Trong et al, 2015) whereas others have reported no benefit (Schultze et al, 2015).…”