Japanese collegiate and club lacrosse games are often held under environmental conditions of extreme heat in the summer. Lacrosse players are also required to wear protective equipment, which is a risk factor for heat-related illness. Nevertheless, the thermoregulatory responses of lacrosse players under such conditions are poorly understood. The present study compared the thermoregulatory responses in subjects wearing the mens' lacrosse uniform or general athletic clothes during an exercise-simulated lacrosse match played in the heat (high temperatures). Eight men performed two experimental trials of 4 × 15-min intermittent cycling exercise in the heat (35°C, 50% relative humidity). All participants performed two trials wearing a lacrosse uniform (WEAR) or general athletic clothes (CON). The physiological strain index was significantly higher (p < 0.05) in the WEAR condition than in CON, and exceeded the high risk level for heat-related illness in WEAR during the 3 rd quarter. Additionally, rectal temperature, skin temperature, heart rate, and ratings for perceived exertion, thermal sensation, and thermal comfort were significantly higher (p < 0.05) in the WEAR condition than in CON. Rectal temperature continued to increase during half-time in the WEAR condition, but not in CON (p < 0.05). These findings indicate that lacrosse players are at a higher risk of heat-related illness compared to other team sport athletes during a match because of the protective equipment worn, especially after half-time. Although further studies are required to confirm the thermoregulatory responses during an actual lacrosse match, our data will be useful in developing strategies to minimize the risk of heat-related illness.

It is well known that excessively elevated core body temperature owing to prolonged exercise in high temperatures causes heat-related illness and has a negative impact on exercise performance. Many articles have been published about effective cooling methods to avoid such impacts on physiological functions in the heat. Ice slurry ingestion has been used by many athletes as a practical and effective cooling strategy. Ice slurry can easily be used on sports fields. Moreover, ice slurry reduces core body temperature more effectively than water alone. Thus, ingestion of ice slurry may be one of the best cooling strategies in hot temperatures. This article provides an overview of the effects of ice slurry ingestion on core body temperature, thermal perception, and exercise performance, and offers practical recommendations in the field that can be adopted by athletes and coaches.

The present study investigated the effects of half-time (HT) break cooling using a fan and damp sponge on physiological and perceptual responses during the 2nd half of a repeated-sprint exercise in a hot environment. Eight physically active men performed a familiarization trial and two experimental trials of a 2×30-min intermittent cycling exercise protocol with a 15-min HT break in hot conditions (35°C, 50% relative humidity). Two experimental trials were conducted in random order: skin wetting with a fan (FANwet) and no cooling (CON). During the 2nd half, a repeated-sprint cycling exercise was performed: i. e., 5 s of maximal pedaling (body weight×0.075 kp) every minute, separated by 25 s of unloaded pedaling (80 rpm) and 30 s of rest. Rectal temperature, skin temperature (chest, forearm, thigh, and calf), heart rate, physiological strain index, rating of perceived exertion, thermal sensation, and comfort were significantly improved in the FANwet condition (P<0.05). There was no significant difference in the repeated-sprint cycling exercise performance between conditions. The results suggest that skin wetting with a fan during the HT break is a practical and effective cooling strategy for mitigating physiological and perceptual strain during the 2nd half in hot conditions.

To reduce the risk of heat-related illness, appropriate body cooling strategies are needed during men’s lacrosse competitions in hot-humid environments. The current study investigated whether additional in-play cooling breaks would attenuate the core (rectal) body temperature rise during exercise designed to mimic the activity patterns of a men’s lacrosse match while wearing uniform in hot-humid environments. In randomized and counterbalanced order, ten physically active men completed two experimental trials comprising four quarters of 15-min intermittent cycling exercises separated by a 10-min simulated half-time break and two 2-min quarter breaks in a climate chamber (35°C, 50% relative humidity). The two trials included a regular simulated match condition (REG) and a water break time out condition (WBTO) that included additional 2-min breaks 7.5-min into each quarter. Rectal temperature was significantly lower (p=0.017) in the WBTO condition (38.23±0.23°C) compared with the REG condition (38.50±0.46°C) at the end of the 4th quarter. In addition, ratings of perceived exertion, thermal sensation, heart rate and the physiological strain index were significantly lower (all p<0.05) in the WBTO condition compared with the REG condition. The current results indicated that, even when wearing lacrosse uniforms, the implementation of WBTO attenuated the core body temperature elevation only in the latter stages of an intermittent cycling exercise protocol designed to mimic the exercise pattern of a men’s lacrosse match. Therefore, WBTO may provide a feasible and effective cooling strategy for lacrosse players to reduce the risk of heat-illness.

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