Ice Vest Research Articles

The Effect of Intermittent Vest Cooling on Thermoregulation and Cardiovascular Strain in Baseball Catchers.

Bishop, SH, Szymanski, DJ, Ryan, GA, Herron, RL, and Bishop, PA. The effect of intermittent vest cooling on thermoregulation and cardiovascular strain in baseball catchers. J Strength Cond Res 31(8): 2060-2065, 2017-Baseball catchers are exposed to multiple physiological challenges while playing outside during the spring and summer months, many of which deal with recovery and thermoregulation. The purpose of this study was to investigate the effect of intermittent cooling on core temperature, cardiovascular strain, exertion, and recovery during a simulated catching performance in the heat. Six trained college-aged baseball catchers performed in a controlled, hot (35° C), and humid (25% relative humidity) environment in a counter-balanced, cross-over design. Ice vest cooling (VC) was used as a cooling modality and was compared with a control of no cooling (NC). Rectal temperature (Tre), heart rate (HR), rating of perceived exertion (RPE), and perceived recovery scale (PRS) were recorded before and after each simulated inning. All activities took place in a heat chamber, and each inning consisted of catchers receiving 12 pitches in their position followed by 6 minutes of recovery. Nine total innings were performed, and 27 total innings were performed with each of the 2 treatments. A significantly smaller mean Tre change was seen in VC when compared with NC (0.58 ± 0.2° C, 0.98 ± 0.2° C, p ≤ 0.01, respectively). Rating of perceived exertion was significantly lower and PRS was significantly improved for VC compared with NC (both p ≤ 0.05). Mean recovery HR during VC was significantly lower than NC in the fifth (VC = 84 ± 8 b·min, NC = 90 ± 9 b·min, p = 0.04), seventh (VC = 84 ± 3 b·min, NC = 92 ± 7 b·min, p = 0.02), and ninth (VC = 85 ± 7 b·min, NC = 93 ± 5 b·min, p = 0.01) innings. Heart rate during catching was significantly lower at the end of the VC trials when compared with NC (108 ± 16 b·min vs. 120 ± 19 b·min, p = 0.02, respectively). Vest cooling decreased heat strain, cardiovascular strain, and RPE while it improved perceived recovery in catchers over a simulated 3-game series performed in hot conditions.

Effects of cooling before and during simulated match play on thermoregulatory responses of athletes with tetraplegia.

Athletes with high level spinal cord injuries (tetraplegia) are under greater thermal strain during exercise than the able-bodied. The purpose of this study was to investigate the effectiveness of pre-cooling using an ice vest and the combination of pre-cooling and cooling during play using water sprays in athletes with tetraplegia. Counter-balanced, cross-over design. Eight wheelchair rugby players with tetraplegia completed a 60min intermittent sprint protocol (ISP) on a wheelchair ergometer in 20.2°C±0.2°C and 33.0%±3.1% relative humidity. The ISP was conducted on three occasions; no cooling (NC), pre-cooling with an ice vest (P) and pre-cooling with an ice vest and water sprays between quarters (PW). Gastrointestinal (Tgi) temperature, mean skin temperature (Tsk) and perceptual responses were measured throughout. At the end of pre-cooling, the change in Tgi was not significantly different between conditions (P>0.05) but the change in Tsk was significantly greater in P and PW compared to NC (P<0.001). The change in Tgi over the ISP was significantly lower in PW and P compared to NC (P<0.05), whilst the change in Tsk was lower in PW compared to P and NC (P<0.05). Cooling had no effect on performance or perceptual responses (P>0.05). Water spraying between quarters combined with pre-cooling using an ice vest lowers thermal strain to a greater degree than pre-cooling only in athletes with tetraplegia, but has no effect on simulated wheelchair rugby performance or perceptual responses.

Effect Of Localized Cooling On Thermo-physiological Responses To Cycling-induced Hyperthermia During Recovery In Thermally-challenging Conditions

PURPOSE: To determine the effects of a phase changing ice-vest and a palm-cooling device on rectal and mean skin temperatures, heart rate (HR), and perceived thermal comfort during a 60 minute recovery period following exercise in the heat. METHODS: Ten recreationally active men and women (25 ± 3 years, VO2 peak: 43.6 ± 7.5 mL·kg -1· min-1) cycled for 60 minutes at 50% VO2 peak on a friction-braked cycle ergometer while exposed to hot environmental conditions (36°C; 45% relative humidity). Following exercise, each subject donned an ice vest, used a palm-cooling device, or sat passively, in randomized order for 60 additional minutes while in hot environmental conditions. Rectal (Tre) and four-site (chest, tricep, quadriceps, calf)) skin (Tsk) temperatures, heart rate (HR), and perceived thermal comfort (TC) were measured every 5 min throughout exercise and recovery. RESULTS: Sixty minutes of cycling in hot environmental conditions elicited an elevation in Tre from baseline across all exercise bouts (PostTre: 38.29 ± .32 °C, Net Tre gain: 1.11 ± .34 °C). Reduction in mean Tsk during the recovery period was significantly greater with the ice vest than the non-cooling condition (MD = 1.20 ± .39 °C, p = 0.042), with specific differences at 10–30, 45, and 55 min of recovery (p < 0.05). Reduction in HR during recovery was found to be significantly greater with the ice vest than the non-cooling condition (MD = 8.5 ± 1.5 b·min-1, p = 0.001) with differences recorded at 5, 15, and 25–60 min of recovery (p < 0.05). Despite Tsk and HR differences, no significant Tre (p = 0.61) or perceived TC (p = 0.24) effects were found between the three recovery conditions. Use of the palm-cooling device was not statistically different than the non-cooling control in any variable measured. CONCLUSION: The use of a phase-changing ice vest following exercise, while still exposed to environmental heat stress, augmented Tsk and HR recovery. This may be attributed to the larger surface area exposed to the cooling stimulus compared to the palm-cooling device. However, this cooling technique was not effective in lowering Tre more than a non-cooling control, which arguably may play a greater role in hyperthermic fatigue. Furthermore, the use of palm-cooling was ineffective in providing thermo-physiological benefit during post-exercise recovery in a hot environment.

Heat‐acclimatization and pre‐cooling: a further boost for endurance performance?

To determine if pre-cooling (PC) following heat-acclimatization (HA) can further improve self-paced endurance performance in the heat, 13 male triathletes performed two 20-km cycling time-trials (TT) at 35°C, 50% relative humidity, before and after an 8-day training camp, each time with (PC) or without (control) ice vest PC. Pacing strategies, physiological and perceptual responses were assessed during each TT. PC and HA induced moderate (+10±18W; effect size [ES] 4.4± 4.6%) and very large (+28±19W; ES 11.7±4.1%) increases in power output (PO), respectively. The overall PC effect became unclear after HA (+4±14W; ES 1.4±3.0%). However, pacing analysis revealed that PC remained transiently beneficial post-HA, i.e., during the first half of the TT. Both HA and PC pre-HA were characterized by an enhanced PO without increased cardio-thermoregulatory or perceptual disturbances, while post-HA PC only improved thermal comfort. PC improved 20-km TT performance in unacclimatized athletes, but an 8-day HA period attenuated the magnitude of this effect. The respective converging physiological responses to HA and PC may explain the blunting of PC effectiveness. However, perceptual benefits from PC can still account for the small alterations to pacing noted post-HA.

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.

Performing in the heat: a new practical midcooling method

Pre-cooling aims to decrease body core temperature prior to [1] and decelerate its rise during exercise preventing excessive hyperthermia [2]. Exercise time to exhaustion in a hot environment is inversely related to the initial body temperature and directly affected by the rate of heat storage [3]. Despite the fact that all ball games involve intermittent activity with at least one long brake among periods, the majority of existing pre-cooling methods are applied before event initiation and use aggressive techniques (cold-water immersion, ice cubes, ice vests). This practice is cumbersome and may initially induce hypothermia, ensuing thermo genesis and discomfort. The purpose of this study was to investigate the effect of a new, practical method for cooling the body during the break (mid-cooling) of a prolonged, high-intensity intermittent exercise in the heat.

Effectiveness of pre-cooling and cooling during play on wheelchair rugby performance

Athletes with tetraplegia (spinal cord injury at the cervical region of the spinal cord) are at a greater risk of heat illness than their able-bodied counterparts, due to the loss of sweating capacity and vasomotor control below the lesion level. Commercially available ice vests worn prior to exercise (pre-cooling) have received considerable interest in the able-bodied athletic population eliciting varying results in performance, and physiological and thermoregulatory responses. However, limited research has been conducted in thermoregulatory impaired athletes with tetraplegia. Anecdotally water spraying the face and torso is commonly used by these athletes during breaks in play, though the effectiveness of this method has not been established. The purpose of this study was to investigate the effects of pre-cooling using an ice vest and the combination of pre-cooling and cooling during play using water sprays on simulated wheelchair rugby performance in athletes with tetraplegia.

The effects of ice vest pre-cooling on skin blood flow at rest and during exercise in the heat

Ice vest pre-cooling has been show to lower rectal tem- perature during intermittent exercise in hot conditions but only after 40 min of exercise [1]. The authors sug- gested that the ice vest may have initiated a strong local cutaneous vasoconstrictor response reducing skin blood flow [2] and thus the cooling potential, until increases in body temperature and skin blood flow occurred later in exercise. Therefore, the purpose of this study was to determine whether ice vest pre-cooling reduces skin blood flow during intermittent exercise in the heat com- pared to a no cooling control.

Effect of Practical Precooling on Neuromuscular Function and 5-km Time-Trial Performance in Hot, Humid Conditions Among Well-Trained Male Runners.

This study investigated whether torso and thigh precooling during a warm-up effects neuromuscular function and 5-km time-trial performance in hot, humid conditions. Eight well-trained male runners completed 3 randomized time-trials in 32.2 ± 0.8° C and 48.6 ± 6.7% relative humidity. A 30-minute warm-up was completed with no cooling (Control), precooling by an ice vest (Vest), or ice packs covering the thighs (Packs). Before the warm-up and after the time-trial, supramaximal femoral nerve stimulation was delivered during and following maximal isometric contractions. Core and skin temperature, heart rate, and perceptual ratings were recorded before and during the warm-up and time-trial. Overall performance time was improved in Packs compared with Control (1,407 ± 80 seconds vs. 1,492 ± 88 seconds; p ≤ 0.05) but not in Vest (1,444 ± 71 seconds; p > 0.05). In Packs, a higher exercise intensity (p ≤ 0.05) and less cumulative time (p < 0.01) were evident during the last kilometer compared with Control. Maximum voluntary force, voluntary activation, muscle contractility, and membrane excitability were not different after exercise or between conditions. Ten minutes after the warm-up, skin temperature was lower in Vest and Packs compared with Control (p < 0.01). Thermal strain and body heat content change was lower in Vest and Packs, respectively (p ≤ 0.05). Findings indicate that torso and thigh precooling during a warm-up reduces thermoregulatory strain. However, thigh opposed to torso precooling provides greater performance improvements. Neuromuscular function did not aid performance, indicating that transient changes in afferent feedback and muscle recruitment may enhance endurance trial performance.

The Effect Of A Mixed Method Pre- And Halftime Cooling Strategy On Soccer Skill Performance

Repeated sprinting ability and skill proficiency are key to success in team sports. Cooling lessens the thermal stress during repeated high intensity exercise, and as a result, better preserves repeated sprinting ability. It is unknown if cooling benefits skill performance. PURPOSE: To examine the effect of a mixed method cooling strategy on thermoregulatory responses and skill performance during simulated soccer in the heat. METHODS: Six male university soccer players completed 1 practice and 2 experimental sessions. In the experimental sessions, players completed 2 soccer halves. Each half consisted of a 36-min soccer specific cycling protocol (40 s at 3.3 Wkg-1 followed by 20 s at 1 Wkg-1 x 36 repeats) in the heat (30-32°C, 40-45% humidity). Skills testing made up the remainder of each half. Skill was assessed with a modified Loughborough Soccer Passing Test (LSPT) and a dribbling test. In one session cooling was applied for 25 min before the 1st half and for 15 min at halftime (COOL). Cooling involved ingestion of a sports drink slushy combined with wearing an ice vest. In the other session (CTL) players ingested sports drink. Core (TC) and tympanic temperature (TTY) were monitored throughout. RESULTS: TC at the start of the 1st half was lower in COOL than in CTL (37.0 ± 0.2 vs. 37.4 ± 0.1 °C; p=0.01). The increase in TC in the 1st half (1.3 ± 0.3 vs. 1.3 ± 0.5 °C), TC at the start of the 2nd half (37.4 ± 0.5 vs. 37.8 ± 0.3 °C), and the rise in TC in the 2nd half (0.9 ± 0.2 vs. 0.8 ± 0.5°C) were not different between COOL and CTL. TTY did not differ between COOL and CTL at any time. In COOL, the time needed to complete the LSPT in the 1st and 2nd half was 37.9 ± 1.1 s and 37.8 ± 0.4 s, respectively. Players amassed 8.1 ± 4.4 s and 5.4 ± 3.1 s of penalty time during these tests. Completion time and penalty time in CTL were 38.0 ± 1.2 s and 6.6 ± 2.3 (1st half) and 38.6 ± 1.7 s and 6.9 ± 4.0 s (2nd half). Time to complete the dribbling test in the 1st half equaled 7.0 ± 0.5 s and 6.9 ± 0.5 s in COOL and CTL. In the 2nd half these times equaled 7.1 ± 0.5 s and 7.2 ± 0.5 s. No between-condition differences were observed for any of the skill variables. CONCLUSION: The combination of ice slushy and ice vest cooling effectively reduced TC prior to the simulated soccer. Although thermal stress was slightly lower during the 1st and 2nd half due to cooling, this did not result in better skill performance.

Cooling athletes with a spinal cord injury.

Cooling strategies that help prevent a reduction in exercise capacity whilst exercising in the heat have received considerable research interest over the past 3 decades, especially in the lead up to a relatively hot Olympic and Paralympic Games. Progressing into the next Olympic/Paralympic cycle, the host, Rio de Janeiro, could again present an environmental challenge for competing athletes. Despite the interest and vast array of research into cooling strategies for the able-bodied athlete, less is known regarding the application of these cooling strategies in the thermoregulatory impaired spinal cord injured (SCI) athletic population. Individuals with a spinal cord injury (SCI) have a reduced afferent input to the thermoregulatory centre and a loss of both sweating capacity and vasomotor control below the level of the spinal cord lesion. The magnitude of this thermoregulatory impairment is proportional to the level of the lesion. For instance, individuals with high-level lesions (tetraplegia) are at a greater risk of heat illness than individuals with lower-level lesions (paraplegia) at a given exercise intensity. Therefore, cooling strategies may be highly beneficial in this population group, even in moderate ambient conditions (~21 °C). This review was undertaken to examine the scientific literature that addresses the application of cooling strategies in individuals with an SCI. Each method is discussed in regards to the practical issues associated with the method and the potential underlying mechanism. For instance, site-specific cooling would be more suitable for an athlete with an SCI than whole body water immersion, due to the practical difficulties of administering this method in this population group. From the studies reviewed, wearing an ice vest during intermittent sprint exercise has been shown to decrease thermal strain and improve performance. These garments have also been shown to be effective during exercise in the able-bodied. Drawing on additional findings from the able-bodied literature, the combination of methods used prior to and during exercise and/or during rest periods/half-time may increase the effectiveness of a strategy. However, due to the paucity of research involving athletes with an SCI, it is difficult to establish an optimal cooling strategy. Future studies are needed to ensure that research outcomes can be translated into meaningful performance enhancements by investigating cooling strategies under the constraints of actual competition. Cooling strategies that meet the demands of intermittent wheelchair sports need to be identified, with particular attention to the logistics of the sport.

Adding a cooling vest during cycling improves performance in warm and humid conditions

It is known that warm and humid environment reduces human physical performance. The present study examined whether the use of an ice-vest in such conditions can improve cycling performance. Seven participants cycled with consecutive, non-stop, 10-minute cycles of nine minutes at 60% of their V ̇ O 2 max punctuated by a one-minute sprint at 80% V ̇ O 2 max. The cycling protocol was continuously repeated until exhaustion. The protocol was performed with the ice-vest (ICE), worn after 30 min of cycling, and without the ice-vest throughout the protocol (CON). Ventilatory and thermal responses were continuously recorded. Electromyographic (EMG) signals from four muscles of the dominant leg were recorded over one minute, and subjective sensations were evaluated at 10-minute intervals. At exhaustion, the exercise time was recorded. Exercise time improved significantly while wearing the ice-vest from 61 min and 29 s to 74 min and 14 s (+21.5%±7.6; p<0.05). Mean power frequency and amplitude of the EMG revealed decreased neuromuscular fatigue during ICE compared to CON. Ventilatory responses indicated a tendency towards lower ventilation, respiratory quotient was significantly lower and both thermal parameters and subjective sensations indicated lower thermal strain during ICE in comparison to CON. These results suggest that wearing an ice-vest during cycling in warm and humid conditions decreases thermal and physical strain, thereby improving cycling performance.

Ice Cooling Vest on Tolerance for Exercise under Uncompensable Heat Stress

This study was conducted to evaluate the effectiveness of a commercial, personal ice cooling vest on tolerance for exercise in hot (35°C), wet (65% relative humidity) conditions with a nuclear biological chemical suit (NBC). On three separate occasions, 10 male volunteers walked on a treadmill at 3 miles per hour and 2% incline while (a) seminude (denoted CON), (b) dressed with a nuclear, biological, chemical (NBC) suit with an ice vest (V) worn under the suit (denoted NBCwV); or (c) dressed with an NBC suit but without an ice vest (V) (denoted NBCwoV). Participants exercised for 120 min or until volitional fatigue, or esophageal temperature reached 39.5°C. Esophageal temperature (Tes), heart rate (HR), thermal sensation, and ratings of perceived exertion were measured. Exercise time was significantly greater in CON compared with both NBCwoV and NBCwV (p < 0.05), whereas Tes, thermal sensation, heart rate, and rate of perceived exertion were lower (p < 0.05). Wearing the ice vest increased exercise time (NBCwoV, 103.6 ± 7.0 min; NBCwV, 115.9 ± 4.1 min) and reduced the level of thermal strain, as evidenced by a lower Tes at end-exercise (NBCwoV, 39.03 ± 0.13°C; NBCwV, 38.74 ± 0.13°C) and reduced thermal sensation (NBCwoV, 6.4 ± 0.4; NBCwV, 4.8 ± 0.6). This was paralleled by a decrease in rate of perceived exertion (NBCwoV, 14.7 ± 1.6; NBCwV, 12.4 ± 1.6) (p < 0.05) and heat rate (NBCwoV, 169 ± 6; NBCwV, 159 ± 7) (p < 0.05). We show that a commercially available cooling vest can significantly reduce the level of thermal strain during work performed in hot environments.

Effect Of Leg Cooling Versus Ice Vest Cooling On Time Trial Paced Cycling

PURPOSE: To test the hypothesis that cooling interventions will enhance performance during a 13-mile simulated time trial in a warm environment. METHODS: Nine trained male cyclists (peak oxygen uptake = 57.8 ± 5.0 mL·kg-1·min-1) completed 3 simulated 13-mile time trials in a warm environment (26.0 ± 0.5 °C, 43.8 ± 3.0 % relative humidity) separated by 72 hours. On each occasion, participants warmed up for 10 min while wearing either an ice vest (VEST) on the torso, cooling packs wrapped around the quadriceps and calves (LEG), or no cooling apparatus (CONTROL). RESULTS: Average core and mean skin temperatures were not significantly different among treatments (all p > 0.05). Likewise, time to completion was not significantly different [39.3 ± 5.2 min (VEST), 40.0 ± 5.2 min (LEG), 41.3 ± 4.2 min (CONTROL), p = 0.25]. Despite a lack of statistical significance, the time trial was completed faster during VEST compared to CONTROL by 7 out of 9 (78%) participants with an average time 3.2 ± 1.9 min faster. Similarly, 5 out of 9 (55%) participants completed the time trial faster during LEG compared to CONTROL with an average time 5.9 ± 1.9 min faster. CONCLUSIONS: These data suggest competitive cyclists may experience a modest benefit while utilizing cooling modalities during an active warm-up before a trial.

The impact of different cooling modalities on the physiological responses in firefighters during strenuous work performed in high environmental temperatures

This study investigated the impact of ice vests and hand/forearm immersion on accelerating the physiological recovery between two bouts of strenuous exercise in the heat [mean (SD), 49.1(1.3)°C, RH 12 (1)]. On four occasions, eight firefighters completed two 20-min bouts of treadmill walking (5 km h, 7.5% gradient) while wearing standard firefighter protective clothing. Each bout was separated by a 15-min recovery period, during which one of four conditions were administered: ice vest (VEST), hand/forearm immersion (W), ice vest combined with hand/forearm immersion (VEST + W) and control (CON). Core temperature was significantly lower at the end of the recovery period in the VEST + W (37.97 ± 0.23°C) and W (37.96 ± 0.19°C) compared with the VEST (38.21 ± 0.12°C) and CON (38.29 ± 0.25°C) conditions and remained consistently lower throughout the second bout of exercise. Heart rate responses during the recovery period and bout 2 were similar between the VEST + W and W conditions which were significantly lower compared with the VEST and CON which did not differ from each other. Mean skin temperature was significantly lower at the start of bout 2 in the cooling conditions compared with CON; these differences reduced as exercise progressed. These findings demonstrate that hand/forearm immersion (~19°C) is more effective than ice vests in reducing the physiological strain when firefighters re-enter structural fires after short rest periods. Combining ice vests with hand/forearm immersion provides no additional benefit.

How to measure thermal effects of personal cooling systems: human, thermal manikin and human simulator study

Thermal effects, such as cooling power and thermophysiological responses initiated upon application of a personal cooling system, can be assessed with (i) humans, (ii) a thermal manikin and (iii) a thermophysiological human simulator. In order to compare these methods, a cooling shirt (mild cooling) and an ice vest (strong cooling) were measured using human participants and a thermal manikin. Under all conditions, cooling was provided for 45 min, while resting at a room temperature of 24.6–25.0 °C and a relative humidity of 22–24%. Subsequently, the thermophysiological human simulator was used under the same conditions to provide data on thermophysiological responses such as skin and rectal temperatures. The cooling power determined using the thermal manikin was 2 times higher for the cooling shirt and 1.5 times higher for the ice vest compared to the cooling power determined using human participants. For the thermophysiological human simulator, the cooling power of the cooling shirt was similar to that obtained using human participants. However, it was 2 times lower for the ice vest when using the thermophysiological human simulator. The thermophysiological human simulator is shown to be a useful tool to predict thermophysiological responses, especially upon application of mild cooling intensity. However, the thermophysiological human simulator needs to be further improved for strong cooling intensities under heterogeneous conditions.

Use of an ice vest to elicit a cold response in neonatal lambs

Use of an ice vest to elicit a cold response in neonatal lambs

A practical cooling strategy for reducing the physiological strain associated with firefighting activity in the heat

The aim of this study was to establish whether a practical cooling strategy reduces the physiological strain during simulated firefighting activity in the heat. On two separate occasions under high ambient temperatures (49.6 ± 1.8°C, relative humidity (RH) 13 ± 2%), nine male firefighters wearing protective clothing completed two 20-min bouts of treadmill walking (5 km/h, 7.5% gradient) separated by a 15-min recovery period, during which firefighters were either cooled (cool) via application of an ice vest and hand and forearm water immersion (∼19°C) or remained seated without cooling (control). There was no significant difference between trials in any of the dependent variables during the first bout of exercise. Core body temperature (37.72 ± 0.34 vs. 38.21 ± 0.17°C), heart rate (HR) (81 ± 9 vs. 96 ± 17 beats/min) and mean skin temperature (31.22 ± 1.04°C vs. 33.31 ± 1°C) were significantly lower following the recovery period in cool compared with control (p < 0.05). Core body temperature remained consistently lower (0.49 ± 0.02°C; p < 0.01) throughout the second bout of activity in cool compared to control. Mean skin temperature, HR and thermal sensation were significantly lower during bout 2 in cool compared with control (p < 0.05). It is concluded that this practical cooling strategy is effective at reducing the physiological strain associated with demanding firefighting activity under high ambient temperatures.

Influence of garment design on elite athlete cooling

High endurance sports in hot and humid conditions are detrimental to both performance and athletes themselves. This has led to an increasing interest in reducing thermal stresses, including the use of personal cooling garments. The design of such garments requires addressing a number of technical and human interface demands. Here we examine the design requirements for effective athlete cooling based on phase change material (PCM) media recognizing the complex heat transport and moisture management processes required within an active cooling garment. The layout and assembly of prototype PCM garments were subsequently optimized in tests in thermally‐stressful environments. The final prototype PCM garment design achieved overall cooling performance comparable to conventional ice vests, although containing approximately half their cooling capacity by avoiding the associated detrimental aspects of ice usage.

Long-Distance Interval Training following Pre-Cooling with an Ice Vest

This study evaluated how preparing for an interval workout, while wearing a cooling vest, affects core temperature (Tc), heart rate (HR), and interval time in long-distance runners. Nineteen male collegiate cross-country runners exercised under two different conditions: (a) wearing a Nike PreCool™ ice vest for one hour prior to the workout (30 minutes resting with the vest and 30 minutes while performing their warm-up); and (b) a control condition utilizing a traditional warm-up. Subjects performed 8 × 1000 m intervals. HR and Tc were measured prior to warm-up, immediately before the first interval, and after each interval. Tc measured before the first interval was significantly lower in the vest condition (difference = 0.37° ± 0.2°C). Differences persisted through the sixth interval. Differences in HR and interval times were nonsignificant between conditions for all intervals Wearing an ice vest prior to and during warm-up effectively lowers Tc during long-distance interval training.