Effect Of Ice Slurry Ingestion Research Articles

Effects of ice slurry ingestion on body temperature and softball pitching performance in a hot environment: a randomized crossover trial

BackgroundAlthough softball players are often required to play in hot environments, scarce evidence is available regarding the effects of ice slurry ingestion on body temperature and pitching performance in softball pitchers in a hot environment. Thus, this study investigated the effects of ice slurry ingestion before and between innings on body temperature and softball pitching performance in a hot environment.MethodsIn a randomized crossover design, seven heat-acclimatized amateur softball pitchers (four males and three females) completed simulated softball games consisting of 15 best-effort pitches per inning for seven innings with between-pitch rest intervals of 20 s. Participants were assigned to either a control trial (CON: ingestion of 5.0 g·kg−1 of cool fluid [9.8 ± 2.2 °C] before simulated softball games and 1.25 g·kg−1 of cool fluid between inning intervals) or an ice trial (ICE: ingestion of ice slurry [− 1.2 ± 0.1 °C] based on the same timings and doses as the CON). Participants performed both trials in an outdoor ground during the summer season (30.8 ± 2.7 °C, 57.0 ± 7.9% relative humidity).ResultsIce slurry ingestion before the simulated softball game (pre-cooling) resulted in a greater reduction in rectal temperature compared with cool fluid ingestion (p = 0.021, d = 0.68). No significant differences were observed between the trials in rectal temperature changes during the simulated softball game (p > 0.05). Compared to the CON, heart rate during the game was significantly decreased (p < 0.001, d = 0.43), and handgrip strength during the game was significantly increased (p = 0.001, d = 1.16) in the ICE. Ratings of perceived exertion, thermal comfort, and thermal sensation were improved in the ICE compared to those in the CON (p < 0.05). Ball velocity and pitching accuracy were not affected by ICE.ConclusionsIce slurry ingestion before and between innings reduced thermal, cardiovascular, and perceptual strain. However, it did not affect softball pitching performance compared to cool fluid ingestion.

Effect of ice slurry ingestion on thermoregulatory responses during fixed-intensity cycling in humid and dry heat.

This study examined the thermoregulatory response and ergogenic effects of ice slurry (ICE) ingestion in hot environments with high and low relative humidity (RH). Eight males completed four trials in a crossover manner in dry (DRY: 34.7 ± 0.2°C, 38 ± 2%RH) and humid heat (HUM: 34.8°C ± 0.2°C, 80 ± 1%RH). They ingested 8.0g·kg-1 of ICE (0.0°C) or 37.5°C water (CON) during 30min before exercise, and three aliquots (3.2g·kg-1) of ICE or CON during 45-min cycling at 50%[Formula: see text]O2peak, followed by cycling to exhaustion at 80%[Formula: see text]O2peak (TTE). Body core temperature (Tcore), mean skin temperature (Tsk), heart rate (HR), thermal comfort, thermal sensation and rating of perceived exertion (RPE) were measured. Relative to CON, ICE improved TTE by 76.5 ± 96.5% in HUM and 21.3 ± 44.9% in DRY (p = 0.044). End-exercise Tcore was lower in ICE versus CON in DRY (37.8 ± 0.4°C versus 38.1 ± 0.3°C, p = 0.005) and HUM (38.8 ± 0.4°C versus 39.3 ± 0.6°C, p = 0.004). ICE decreased HR, heat storage and heat strain index only in DRY (p < 0.001-0.018). ICE improved thermal sensation and comfort in DRY and HUM (p < 0.001-0.011), attenuated RPE in HUM (p = 0.012) but not in DRY (p = 0.065). ICE tended to benefit performance in humid heat more than in dry heat. This is likely due to the reduced extent of hyperthermia in dry heat and the relative importance of sensory inputs in mediating exercise capacity.

Effect of Ice Slurry Ingestion on Post-Exercise Physiological Responses in Rugby Union Players

Delayed recovery of the core body temperature after exercise adversely affects physiological functions, and the effects of ingesting lower-temperature ice slurry on post-exercise recovery remain unclear. We investigated the effects of ingesting −2 °C ice slurry on physiological recovery after field-based rugby union training. Fifteen university rugby union players participated in our randomized controlled study. The players participated in the training for 60 min in a hot outdoor environment (wet-bulb globe temperature, 30.5 °C). Physiological responses were measured during a physical performance test performed after the players ingested either −2 °C-ice slurry (ICE, N = 7) at 5 g/kg body mass or a 30 °C-fluid (CON, N = 8) during the 15 min recovery period after the training. Tympanic temperatures and heart rates were measured as the physiological indices, as well as heat storage. The ICE group showed significantly decreased tympanic temperatures and heart rates (p &lt; 0.05) during the recovery period and increased heat storage (p &lt; 0.05) but did not show improvement of physiological indices during the performance test compared to the CON group. These results suggest that ingestion of −2 °C ice slurry in even lower amounts than those previously reported is useful for physiological recovery after training in hot outdoor environments.

Comparison of the effect of post-exercise cooling with ice slurry ingestion between males and females.

This study aimed to compare the effects of ice slurry ingestion on post-exercise cooling in males and females. Twenty-four healthy adults (male n=12; body weight [BW], 65.8±10.3kg; female, n=12; BW, 58.2±10.0kg) participated in this study. Participants ingested 7.5g/kg of either ice slurry at -1°C (ICE) or control fluid at 20°C (CON) during recovery after cycling at 55% VO2max until the rectal temperature reached 38.5°C or exhaustion in a hot environment (controlled at 38°C, 40% relative humidity). Rectal (Tre) and skin (Tsk) temperature, ratings of thermal sensation (TS), thermal comfort (TC), heart rate (HR), mean arterial pressure (MAP), and whole body sweat loss (WBSL) were measured 60min after exercise. Ice slurry ingestion reduced Tre and TS and improved post-exercise hypotension only in females (p<0.05). In comparison, males did not receive cooling effect from post- exercise cooling with ice slurry ingestion. WBSL tended to be lower in ICE than CON in males (ICE, 454.3±172.3g; CON, 539.7±157.2g; p=0.065). In conclusion, sex differences were observed in the effects of post-exercise cooling with ice slurry ingestion.

Effect of ice slurry ingestion on core temperature and blood pressure response after exercise in a hot environment.

Delays in the restoration of thermoregulation after exercise in a hot environment has been associated with post-exercise hypotension. This study tested the hypothesis that simultaneous internal cooling and rehydration by ingesting ice slurry prevents the excessive decrease in mean arterial pressure (MAP) and promotes recovery of core and skin temperatures in male athletes. Seven male athletes participated in this randomized controlled trial with a crossover design. The participants ran on a treadmill at 75% of their maximal oxygen uptake in the heat (35°C, 60% relative humidity), up to exhaustion. Immediately after exercise, participants ingested either 4g⋅kg -1 body weight of ice slurry (0.5°C, ICE) or a control beverage (28°C, CON). The participants then recovered by sitting for 20min. We measured participants' rectal temperature (Tre), skin temperature (Tsk), mean arterial pressure (MAP), heart rate (HR), cardiac output (CO), total peripheral resistance (TPR), and physiological strain index (PSI) before exercise (Pre), after running to exhaustion (PEx), and at 0 (P0), 10 (P10), and 20 (P20) minutes after ice slurry or control beverage ingestion. MAP, CO, HR, TPR, or PSI did not change significantly during the recovery period. At P10 and P20, Tre and Tsk significantly decreased in the ICE group compared to the CON group (p<0.05). These results suggested that ingestion of ice slurry, post-exercise, promoted core and skin temperature recovery but did not affect the central and peripheral cardiovascular responses during the acute recovery period.

Cooling during short-term heat acclimation enhances aerobic capacity but not sweat capacity

ABSTRACT To characterize the adaptive responses to short-term heat acclimation (HA) training with repeated-sprint exercises and to determine the effects of ice slurry ingestion during HA on aerobic capacity and adaptations. Seven physically active males completed two 5 consecutive day interventions in a randomized cross-over design. Participants performed approximately 80-min intermittent repeated-sprints using a cycling ergometer including break-time and half time in 36.5°C and 50%RH. Participants ingested either 1.25 g·kg body mass−1 of ice slurry (ICE: −1°C) or room temperature beverage (NOC: 36.5°C) throughout each break and 7.5 g·kg body mass−1 of the same drink during half time. Maximum oxygen uptake (O2max) test in hot conditions was completed before and after HA training. Ice slurry ingestion during short-term HA training induced significantly higher both O2max and watt at O2max following HA training. Total work done was significantly higher in HA with ICE than for the NOC trial on both day 1 and day 5. Sweating Na+ concentration in NOC trial at day 5 were significantly lower than those in the NOC trial day 1, but was not observed in ICE trial. Cooling during HA training may be an effective strategy for enhancement of aerobic capacity via the adaptations gained from a higher quantity of exercise caused by cooling, but does not improve heat loss capacity. Highlights There is the potential dilemma whether cooling during short-term training in the heat might negatively impacts the process of helping athletes adapt to hot environments. Cooling during short-term heat training may be an effective strategy to enhancement of aerobic capacity via the adaptations gained from a higher quantity of exercise caused by cooling, but does not improve heat loss capacity. The study suggests the importance to selecting cooling during the heat acclimation phase of consecutive field training according to the individual's training plan.

Impact of Ice Slurry Ingestion During Break-Times on Repeated-Sprint Exercise in the Heat.

The study aimed to investigate the effects of ice slurry ingestion during break times and half-time (HT) on repeated-sprint performance and core temperature in the heat. Seven males performed two different trials as follows: ice slurry (−1°C) or room temperature water ingestion at each break and HT break at 36.5°C, 50% relative humidity. Participants performed 30 sets of 1-min periods of repeated- sprint exercises protocol using a cycling ergometer. Each period consisted of 5 sec of maximal pedaling, 25 sec of pedaling with no workload, and 30 sec of rest; two sets of exercise periods were separated by 10 min of rest. Each break was implemented for 1 min after every 5 sets. The rectal temperature in ice slurry ingestion was significantly lower than that of the room temperature water at 45 set (p=0.04). Total and mean work done was greater in ice slurry ingestion compared to room temperature water ingestion (p < 0.05). These results suggested that ice slurry ingestion during break times and HT break may be an effective cooling strategy to attenuate the rise of core temperature in the second half of exercise and improve the repeated-sprint exercise capacity in the heat.

Effects of Ice-slurry Ingestion on Body Internal Cooling for Firefighters in Heat

Effects of Ice-slurry Ingestion on Body Internal Cooling for Firefighters in Heat

Effect of Ice Slurry Ingestion on Cardiovascular Drift and V˙O2max during Heat Stress

This study aimed to test the hypothesis that ice slurry ingestion attenuates the magnitude of CV drift and accompanying decrement in V˙O2max during heat stress. Eight men completed a graded exercise test on a cycle ergometer in 22°C to measure V˙O2max. Then on three separate occasions (in randomly assigned counterbalanced treatment orders), they cycled at 60% V˙O2max in hot conditions (35°C, 40% RH) for 15 min, 45 min with tepid (23°C) fluid ingestion (45FL), or 45 min with ice (-1°C) slurry ingestion (45ICE), followed immediately by measurement of V˙O2max. The purpose of the separate 15- and 45-min trials was to measure CV drift and V˙O2max over the same time interval. The increase in heart rate between 15 and 45 min was twice as large in 45FL (8.6%) compared with 45ICE (4.6%; P = 0.02). Stroke volume declined by 6.2% in 45FL but was maintained with 45ICE (P = 0.02). V˙O2peak decreased from 15 to 45 min by 8.6% and 9.0% in 45FL and 45ICE, respectively, but was not different between conditions (P = 0.79). Although ice slurry ingestion attenuated CV drift more than fluid ingestion, it did not mitigate the decline in V˙O2max. Contrary to previous findings, when ice slurry is ingested, changes in heart rate may not reflect changes in relative metabolic intensity during prolonged exercise in the heat.

Ice slurry ingestion during break times attenuates the increase of core temperature in a simulation of physical demand of match-play tennis in the heat

ABSTRACTThis investigation assessed the effect of ice slurry ingestion compared to that of cold water ingestion during break times on thermal strain and perception in simulated match-play tennis in the heat. Seven male recreational athletes (age = 22 ± 2 yr, height = 1.72 ± 0.08 m, Body mass = 64.8 ± 6.8 kg) performed two trials in a climate chamber, each time completing 4 sets of simulated match-play. During International Tennis Federation-mandated breaks (90-s between odd-numbered games; 120-s between sets), either ice slurry or cold water were ingested. The rectal temperature, forehead skin temperature, heart rate, rating of thermal comfort and total sweat loss were measured. The change in rectal temperature in the ice slurry trial was significantly lower than that in the cold water trial by game 3 of set 3 (p = 0.02). These differences in Δrectal temperature persisted throughout the remainder of the “match” (p < 0.05). Forehead skin temperature, heart rate and rating of thermal comfort were significantly lower in the ice slurry trial than in the cold water trial by the second half of the experiment (p < 0.05). Total sweat loss in ice slurry trial is significantly lower than cold water trial (p = 0.002). These results suggested that ice slurry ingestion was more effective than cold water ingestion in mitigating the development of heat strain during simulated match-play tennis in the heat.

Ice Slurry Ingestion and Physiological Strain During Exercise in Non-Compensable Heat Stress

Precooling with ice slurry ingestion attenuates the increase in rectal temperature (Tre) during subsequent running and cycling. It remains unclear how this cooling method affects physiological strain during work while wearing protective garments. This study investigated the effect of ice slurry ingestion on physiological strain during work in hot conditions while wearing firefighter protective clothing. In three counterbalanced trials, eight men (mean ± SD; age = 21 ± 2 yr, height = 179.5 ± 3.5 cm, mass = 79.1 ± 4.1 kg, body fat = 11.4 ± 3.7%) wore firefighter protective clothing and walked (4 km · h-1, 12% incline, ∼7 METs) for 30 min in hot conditions (35°C, 40% RH). Every 2.5 min, subjects ingested 1.25 g · kg-1 (relative total: 15 g · kg-1, absolute total: 1186.7 ± 61.3 g) of a tepid (22.4 ± 1.7°C), cold (7.1 ± 1.5°C), or ice slurry (-1.3 ± 0.2°C) beverage. Heart rates (HR) were lower with ice slurry ingestion compared to both fluid trials starting 5 min into exercise (tepid = 158 ± 14, cold = 157 ± 11, ice slurry = 146 ± 13 bpm) and persisting for the remainder of the bout (min 30: tepid = 196 ± 10, cold = 192 ± 10, ice slurry = 181 ± 13 bpm). Tre was lower with ice slurry ingestion compared to cold and tepid trials (min 5: tepid = 37.17 ± 0.38, cold = 37.17 ± 0.39, ice slurry = 37.05 ± 0.43°C; min 30: tepid = 38.15 ± 0.29, cold = 38.31 ± 0.36, ice slurry = 37.95 ± 0.32°C). The physiological strain index (PSI) was lower with ice slurry ingestion compared to fluid trials starting at min 5 (tepid = 3.8 ± 0.7, cold = 3.8 ± 0.6, ice slurry = 3.0 ± 0.5) and remained lower throughout exercise (min 30: tepid = 8.2 ± 0.6, cold = 8.3 ± 0.9, ice slurry = 6.9 ± 1.2). A large quantity of ice slurry ingested under non-compensable heat stress conditions mitigated physiological strain during exercise by blunting the rise in heart rate and rectal temperature.Ng J, Wingo JE, Bishop PA, Casey JC, Aldrich EK. Ice slurry ingestion and physiological strain during exercise in non-compensable heat stress. Aerosp Med Hum Perform. 2018; 89(5):434-441.

Ice slurry ingestion reduces human brain temperature measured using non-invasive magnetic resonance spectroscopy

We previously reported that ice slurry ingestion reduced forehead skin temperature, thereby potentially reducing brain temperature (Tbrain). Therefore, in the current study, we investigated the effect of ice slurry ingestion on Tbrain using proton magnetic resonance spectroscopy, which is a robust, non-invasive method. Eight male participants ingested 7.5 g/kg of either a thermoneutral drink (37 °C; CON) or ice slurry (−1 °C; ICE) for about 5 min following a 15-min baseline period. Then, participants remained at rest for 30 min. As physiological indices, Tbrain, rectal temperature (Tre), mean skin temperature, nude body mass, and urine specific gravity were measured. Subjective thermal sensation (TS) and thermal comfort (TC) were measured before and after the experiment. Tbrain and Tre significantly reduced after ingestion of ICE compared with after ingestion of CON, and there was a significant correlation between Tbrain and Tre. The other physiological indices were not significantly different between beverage conditions. TS and TC were significantly lower with ICE than with CON (p < 0.05). These results indicate that ice slurry ingestion can cool the brain, as well as the body’s core.

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

The effects of pre cooling on endurance performance are widely known. In contrast, the approach of cooling during endurance exercise in combination with pre-exercise cooling has been poorly understood. The purpose of the present study was to determine whether the effects of precooling and cooling during exercise enhance exercise performance compared to the ingestion of a thermo-neutral beverage (20 °C) or precooling alone in cycling performance. This was an experimental study using a randomised crossover design in which 7 cyclists underwent three trials comprising of 45 min steady state cycling (SS) at 70% VO2 max and a subsequent 10 km time trial (TT) in hot conditions (32 °C, 50% relative humidity). Rectal temperature (Tre), heat storage (HS), heart rate (HR), blood lactate concentration (BLA) and thermal sensation (TS) were measured. The intervention consisted of: (1) ingestion of thermo-neutral beverage before and during SS cycling (TN), (2) ingestion of ice slurry beverage and application of iced towels (precooling) prior to exercise, and then ingestion of thermo-neutral beverage during SS (PRE) and (3) precooling strategy as above plus ice slurry ingestion during SS cycling (PRE + MID). The intake of thermo-neutral or ice slurry beverage (14 g/kg) occurred over 30 min before and every 15 min during SS cycling. There was no significant difference in TT performance between all the conditions (P =0.72). However, PRE and PRE + MID caused a significant decrease in Tre (P < 0.05) from TN during exercise. Accordingly, both precooling and a combination of precooling and mid-cooling during exercise in hot conditions may be a practical and effective way of reducing core temperature. Future studies should investigate longer distance events and timing of ice slurry ingestion.

Effect of Ice Slurry Ingestion on Cardiovascular Drift and Maximal Oxygen Uptake During Heat Stress

Effect of Ice Slurry Ingestion on Cardiovascular Drift and Maximal Oxygen Uptake During Heat Stress

The effect of ice ingestion during endurance exercise

When exercising in a hot and humid environment, athletes encounter thermoregulatory strain leading to decreased central neurological drive and reduced skeletal muscle activation [1]. Reducing initial core temperature prior to exercise increases the capacity to store metabolic and environmental heat [2]. It has been also found that ice 'slurry' ingestion is an effective precooling strategy reducing rectal temperature (Tre) [5]. The purpose of this study was to compare the effects of ice slurry ingestion before exercise in the heat with combined precooling (with ice slurry) and ingestion of ice slurry during exercise on endurance performance in hot conditions.

The effect of ice slurry ingestion on intermittent activity and a run to exhaustion in the heat

Major competitions are often staged in hot environments. However, the body's ability to dissipate heat is compromised during heat stress resulting in a concomitant rise in core temperature (Tc), ultimately leading to impaired performance. Precooling methods such as ice vests and cold water immersion are employed before competition, to lower Tc and increase heat storage before a critical Tc is reached. However, there are numerous practical limitations meaning pre-existing methods are impractical for use in a field setting. Ice slurry ingestion has been investigated as a more practical precooling method and has enhanced endurance performance [1], however research has yet to determine its effects upon intermittent activity. Therefore the aim of this study was to determine the efficacy of ice slurry ingestion as a precooling method prior to intermittent activity and a run to exhaustion in the heat.

The Effects of Ice Slurry Ingestion on Exercise In The Heat While Wearing Firefighting Clothing

The Effects of Ice Slurry Ingestion on Exercise In The Heat While Wearing Firefighting Clothing

Ice slurry ingestion reduces both core and facial skin temperatures in a warm environment

Internal body cooling by ingesting ice slurry has recently attracted attention. Because ice slurries are ingested through the mouth, it is possible that this results in conductive cooling of the facial skin and brain. However, no studies have investigated this possibility. Thus, the aim of this study was to investigate the effects of ice slurry ingestion on forehead skin temperature at the point of conductive cooling between the forehead skin and brain. Eight male subjects ingested either 7.5g/kg of ice slurry (−1°C; ICE), a cold sports drink (4°C; COOL), or a warm sports drink (37°C; CON) for 15min in a warm environment (30°C, 80% relative humidity). Then, they remained at rest for 1h. As physiological indices, rectal temperature (Tre), mean skin temperature, forehead skin temperature (Thead), heart rate, nude body mass, and urine specific gravity were measured. Subjective thermal sensation (TS) was measured at 5-min intervals throughout the experiment. With ICE, Tre and Thead were significantly reduced compared with CON and COOL conditions (p<0.05). The results of the other physiological indices were not significantly different. TS with ICE was significantly lower than that with CON and COOL (p<0.05) and was correlated with Tre or Thead (p<0.05). These results indicate that ice slurry ingestion may induce conductive cooling between forehead skin and brain, and reduction in core and forehead skin temperature reduced thermal sensation.

The Effects of Ice Slurry Ingestion before Exertion in Wildland Firefighting Gear

Purpose. To investigate the effect of ice slurry ingestion precooling on body core temperature (Tc) during exertion in wildland firefighting garments in uncompensable heat stress. Methods. On two separate trials, 10 males ingested 7.5 g·kg−1 of either an ice slurry (0.1°C) or control beverage (20°C) during seated rest for 30 minutes prior to simulating the U.S. Forest Service Pack Test on a treadmill in wildland firefighting garments in a hot environment (38.8 ± 1.2°C, 17.5 ± 1.4% relative humidity). Deep gastric temperature, mean skin temperature (Tsk), and heart rate (HR) were recorded. Ratings of perceived exertion, thermal sensation, comfort, and sweating were assessed. Results. Compared with ingestion of a temperate beverage, precooling with ice slurry before exertion in a hot environment reduced Tc during the first 30 minutes of the exercise bout. Exercise time and distance completed were not different between treatments. Skin temperature, heart rate, and perceptual responses rose in both conditions during exercise but did not differ by condition. Conclusion. Pretreatment with ice slurry prior to exertion in wildland firefighting garments results in a modest reduction in Tc during the first 30 minutes of exercise when compared to pretreatment with control beverage but the ice slurry precooling advantage did not persist throughout the 45-minute exercise protocol.

Ice slurry ingestion during cycling improves Olympic distance triathlon performance in the heat

This study investigated the effect of ice slurry ingestion during a triathlon on intragastric temperature and 10 km running performance in the heat. Nine well-trained male triathletes performed two randomised trials of a simulated Olympic distance triathlon in hot conditions (32–34°C). Exercise intensity during the swim (1500 m) and cycle (1 hr) legs was standardised, and the 10 km run leg was a self-paced time trial. During the cycle leg, either 10 g · kgBM−1 of ice slurry (< 1°C) or room temperature fluid (32–34°C) was ingested. In the run leg of the ice slurry trial, performance time (43.4 ± 3.7 vs. 44.6 ± 4.0 min; P = 0.03), intragastric temperature (at 1.5 km; 35.5 ± 1.2 vs. 37.5 ± 0.4°C; P = 0.002) and perceived thermal stress (at 5 km; 73 ± 9 vs. 80 ± 7 mm; P = 0.04) were significantly lower. Oxygen consumption was significantly higher in the ice trial between 9.5–10 km (52.4 ± 3.4 vs. 47.8 ± 5.4 mL · kg−1 · min−1; P = 0.04). The results suggest ice slurry ingestion was an effective ergogenic aid for triathlon running performance in the heat. The attenuation of intragastric temperature and perceived thermal stress were likely contributors to the self-selection of a higher running intensity and improved performance time.