Journal of Sports Science and Medicine
Journal of Sports Science and Medicine
ISSN: 1303 - 2968   
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©Journal of Sports Science and Medicine (2022) 21, 164 - 170   DOI: https://doi.org/10.52082/jssm.2022.164

Research article
Ice Ingestion Maintains Cognitive Performance during a Repeated Sprint Performance in The Heat
Nur Shakila Mazalan1,3, , Grant Justin Landers1, Karen Elizabeth Wallman1, Ullrich Ecker2
Author Information
1 School of Human Sciences (Exercise and Sports Science), The University of Western Australia, Crawley, WA, Australia
2 School of Psychological Science, The University of Western Australia, Crawley, WA, Australia
3 Faculty of Education, National University of Malaysia, Bangi, Selangor, Malaysia

Nur Shakila Mazalan
✉ School of Human Sciences (Exercise and Sports Science), The University of Western Australia, Crawley, WA, Australia
Email: nurshakila.mazalan@research.uwa.edu.au
Publish Date
Received: 26-11-2021
Accepted: 08-03-2022
Published (online): 01-06-2022
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ABSTRACT

This study investigated the effects of precooling via crushed ice ingestion on cognitive performance during repeated-sprint cycling in the heat. Nine males, non-heat acclimatised to heat (mean age: 28.2 ± 2.7 y; height: 175.7 ± 9.7 cm; body-mass: 76.9 ± 10.6 kg) completed a 30 min bout of repeated-sprint (36 × 4 s sprints, interspersed with 56 s rest-breaks) on a cycle ergometer in a climate chamber (35°C, 70% relative humidity). Crushed ice ingestion (7g·kg-1, -0.4°C, ICE) or no cooling (CON) interventions were completed at rest, in the climate chamber, 30 min prior to exercise. Working memory was assessed via the serial seven test (S7) and the automated operation span task (OSPAN) at various time points before, during, and post-exercise. Core body temperature (Tc), forehead temperature (Th), and thermal sensation (TS) were assessed throughout the protocol. Working memory significantly declined during exercise in CON as measured by S7 (p = 0.01) and OSPAN (p = 0.03); however, it was preserved in ICE with no change at the end of exercise in either S7 or OSPAN scores compared to baseline (p = 0.50, p = 0.09, respectively). Following precooling, Th (-0.59°C, p < 0.001) and Tc (-0.67°C, p = 0.005) were significantly decreased in ICE compared to CON. At the end of the exercise, ICE significantly reduced Tc compared to CON (p = 0.03), but no significant differences were recorded for Th. Further, TS was lower following precooling in ICE (p = 0.008) but not during exercise. In conclusion, ice ingestion significantly reduced Th and Tc and facilitated maintenance of cognitive performance during repeated-sprint exercise in the heat, which may lead to better decision making.

Key words: Precooling, cognitive function, team sport, forehead temperature


           Key Points
  • Thirty minutes of precooling via crushed ice ingestion able to preserve and maintain cognitive efficiency (working memory) during repeated-sprint exercise in the heat compared to no cooling trial.
  • The preservation and maintenance in cognitive performance is associated with a reduction in T and T following crushed ice ingestion prior to repeated-sprint exercise in the heat.
  • Crushed ice ingestion significantly reduced TS after cooling but the cooling sensation was observed to diminish during the exercise.

INTRODUCTION

In team sports, many major competitions are carried out in hot and humid environments where ambient conditions can exceed 30°C and 70% relative humidity (RH). For example, more than 25% of football matches during the 2014 World Cup in Brazil were played under heat stress (Nassis et al., 2015), while the 2022 World Cup is scheduled to be played in Qatar, where ambient temperatures can average ~30°C. Exercising in hot and humid conditions increases core body temperature (Tc) and can increase cardiovascular strain (increased heart rate and decreased stroke volume; Periard et al., 2021). Notably, a Tc ≥ 38.5°C (hyperthermia: Knochel and Reed, 1994) can result in the impairment or early termination of both endurance and repeated-sprint exercise (Drust et al., 2005; Girard et al., 2015; Gonzalez-Alonso et al.1999; Sunderland and Nevill, 2005). Further, the same Tc threshold is also used for clamped hyperthermia research by implementing a physiological controlled approach (fixed Tc during exercise, Periard et al., 2021). Although 38.5°C may represent a typical threshold, some people are able to withstand higher Tc and perform successfully (Racinais et al., 2019). Cognitive task performance relying on attention and working memory functions have also been reported to be impaired when Tc ≥ 38.5°C (Bandelow et al., 2010; Hocking et al., 2001; Schmit et al., 2017), thus potentially limiting the ability of those affected to process information effectively during exercise (Kenefick et al., 2007).

Effective cognitive processing refers to the mind’s ability to evaluate multiple pieces of information and then make appropriate decisions. This involves the limited-capacity systems of attention and working memory (Brown, 1996). Impairment in cognitive performance whilst exercising in the heat (Donnan et al., 2021) has been attributed to a reduction in cerebral blood flow (Nybo and Nielsen, 2001). This decrease in blood flow is likely due to blood being diverted to the periphery (for cooling) and the working muscles that extract oxygen from the blood for energy production (Falkowska et al., 2015). This can result in less oxygen and nutrients flowing to the brain, leading to transient cognitive impairment. Additionally, reduced cerebral blood flow may impair heat removal from the brain (Nybo et al., 2002), leading to increased brain temperature and potentially compounding cognitive deficits (Hocking et al., 2001).

Precooling has been used as a strategy to counteract the negative effects of heat on subsequent exercise and cognitive performance. Precooling has been found to be effective in reducing pre-exercise Tc, consequently delaying the onset of thermally induced fatigue by providing greater heat storage capacity (Zimmermann et al., 2017). This in turn has resulted in improved subsequent cognitive performance assessed before and after endurance exercise in the heat (Saldaris et al., 2019; 2020). Specifically, Saldaris et al. (2020) reported that working memory and decision-making were maintained pre and post 90 min of running at 65% V̇O2peak in hot and humid conditions following precooling with 7 g·kg-1 of crushed ice ingestion, compared to no-cooling. These researchers suggested that crushed ice ingestion cooled the blood in the carotid arteries via conduction, which then flowed to the brain, thus cooling the brain. While benefit has been found for precooling on cognitive performance prior to and after endurance exercise, its impact in respect to repeated-sprint performance has not been well researched.

Compared to endurance exercise, prolonged repeated-sprint performance in the heat results in lower peak Tc (~38.5 versus ~40.0°C) and peak heart rate (~160 bpm versus ~170 bpm: Brade et al., 2013; Maroni et al., 2018, Maroni et al., 2019). These differences are most likely due to the inclusion of regular rest intervals during repeated-sprint performance (≤60 s per break; Girard et al., 2011), which may result in lower metabolic heat production, compared to endurance performance. Nonetheless, peak Tc during repeated-sprint performance can still become hyperthermic and exceed levels associated with cognitive impairment (i.e., 38.5°C). Thus, when exposed to hot ambient conditions, team-sport athletes may not be able to maintain a level of cognitive function needed to assist in accurate decision-making (Smits et al., 2014). To date, no studies have assessed the effect of precooling using ice ingestion on subsequent cognitive performance when performing repeated-sprints in the heat. Therefore, the aim of this study was to examine the effects of crushed ice ingestion (precooling) on cognitive function assessed prior to, during and after repeated-sprint exercise in hot and humid conditions. It was hypothesised that crushed ice ingestion would reduce Tc, Th and subsequently maintain cognitive performance assessed at various time points when performing repeated-sprint exercise in the heat, compared to a no-cooling control.

METHODS

Participants

Nine healthy, trained, team-sport athletes were recruited to this study (mean age: 28.2 ± 2.7 y; height: 1.76 ± 0.10 m; body-mass: 76.9 ± 10.6 kg; body surface area: 1.90 ± 0.17 m2). All participants were informed of the details and requirements of the study. Written informed consent was provided from each participant prior to testing. Ethical approval was granted from the Human Research Ethics of Committee of the University (RA/4/20/6057).

Experimental overview

This cross-over study consisted of one familiarisation session and two experimental trials. All trials were performed at the same time of the day, one week apart. Experimental trials consisted of 30 min of repeated-sprint cycling (36 × 4 s sprints) preceded by 30 min of precooling where participants either ingested 7 g·kg-1 of crushed ice (-0.4°C; ICE), which had been crushed with a commercial ice crusher (Avalanche, Sunbeam, Australia), or ingested the same amount of room temperature tap water (35°C; CON). Trials were completed in a randomised order.

Familiarisation session

One week prior to the experimental trials, height (Seca, West Germany, Germany) and nude body-mass (model ED3300; Sauter Multi-Range, Ebingen, West Germany) were recorded. Participants were familiarised with the cognitive tasks (automated operation span test; OSPAN and serial seven test; S7), perceptual response scale (thermal sensation), and completed the 30 min repeated-sprint cycling protocol in the climate chamber (35°C, 70% RH).

Experimental protocol

Participants refrained from any strenuous exercise, ingestion of alcohol and caffeine 24 h prior to each testing session. During the same 24 h period participants recorded food and physical activities into personal diaries and then followed the same diet and activity regime prior to the subsequent experimental trial. Participants ingested a telemetry capsule (CorTemp®, Palmetto, FL, USA) eight hours prior to each trial to assess Tc.

Upon arrival to the laboratory, a mid-stream urine sample was collected to determine participants’ hydration levels (TE-RM10SG, 1.000-1.070, Test Equip, Dandenong, Australia) via urine-specific gravity. If hypohydration occur (USG > 1.030), participants then consumed an additional 500 ml of water. No participants were found to be hypohydrated (i.e., USG > 1.030). A skin thermistor (Skin Sensor SST-1, Physitemp Instruments Inc, NJ, USA) was taped to the middle of the forehead, to assess forehead temperature (Th) via a computerised program (DASYLab Light, National Instruments, Ireland Resources Ltd., USA).

Participants then entered the climate chamber (35°C, 70% RH) and completed the OSPAN test (10 min) and the S7 test (1 min) in a seated position. Participants remained seated and undertook either experimental intervention (crushed ice ingestion, ICE or ingested tap water, CON) 30 min prior to exercise. Participants completed the S7 test again after the rest period. The exercise trials began with a standardised 5 min cycling warm-up that included 2 x 4 s maximal sprints at 3.5 and 4.5 min followed by the 30 min repeated-sprint protocol.

The repeated-sprint protocol comprised of 30 x 4 s maximal sprints every 1 min (4 s sprint followed by 56 s active recovery ranging at 25-100 W). Additionally, six maximal 4 s sprints were performed at 2.5, 7.5, 12.5, 17.5, 22.5, 27.5 min to replicate the unpredictable nature of team-sport. The repeated-sprint protocol was adopted from a study by Brade et al. (2013). The exercises were performed on a calibrated front access cycle ergometer (Model EX-10, Repco, Victoria, Australia). During exercise, participants ingested 100 ml of tap water (room temperature) every 10 min to offset sweat losses. The S7 test was performed again after 27 min of exercise whilst cycling, while the OSPAN was performed again after completing the exercise. Throughout the exercise, thermal sensation (TS; 0 = unbearably cold to 8 = unbearably hot, Young et al., 1987) was measured every 5 min.

Cognitive tests

The OSPAN task assesses working memory capacity (Turner and Engle, 1989). This test is a computerised cognitive test administered using Inquisit 5 software (Millisecond Software, USA) and requires participants to remember correctly the serial order of presented letters and simultaneously answer math problems as a secondary task distractor (e.g., (8 / 4 + 3 = ?) as rapidly as possible. This test takes ~10 min to complete. There were 15 sets of trials in total where each set size ranged from 3-7 letters and included varied math problems. In total, there were 75 letters to be remembered and 75 math problems to be solved, with the presentation of these variables randomly programmed by the software for each session. The outcome measure was the sum of the total number of correct answers, with a total mark of 75 (Bayliss et al., 2003). The task’s internal consistency is α = 0.78, while test-retest reliability coefficients have been recorded to be 0.83 (Unsworth et al., 2005). This task has been previously used to assess cognitive performance during exercise in the heat (Mazalan et al., 2021).

The S7 test assesses attention and working memory (Bristow et al., 2016). Participants were required to count down out loud from any random number given (between 900 to 1000) by sevens in 1 min (similar to Hayman, 1942). Any mistake in calculations were carried on by subtracting from the current number given. The outcomes measured were the total number of correct and incorrect answers. The test was administered verbally at three-time points during exercise (prior to precooling, after precooling and 3 min before the end of exercise).

Statistical analyses

All statistical data were analysed using the IBM Statistical Package for Social Sciences version 28.0 (SPSS Inc, Chicago, IL, USA); descriptive statistics were presented as mean ± standard deviation unless otherwise stated. Data was assessed for normality (Shapiro-Wilk test) and sphericity (Mauchly’s test). Two-way, repeated-measures ANOVAs were performed on the data to test for condition differences. Statistical significance was set at p ≤ 0.05. Where main interaction effects occurred, post hoc comparisons (Bonferroni) were conducted and paired sample t-tests were used to identify specific condition differences if significance was found. In addition, Cohen’s d effect sizes (ES) were used to identify meaningful differences in the data (Cohen, 1988) with only moderate (0.5-0.8) and large (>0.8) ES reported. All values are expressed as mean ± SD.

RESULTS

There were no differences in environmental conditions (p > 0.05; 34.9 ± 0.9° C, 70.1 ± 6.8 % RH) or the amount of total work done (CON: 108540 ± 19747 Joule [J], ICE: 110654 ± 20895 J, p > 0.05) between trials.

Serial seven scores significantly declined over time in CON compared to baseline (-3, p = 0.01, d = 1.5, 0.36 to 2.43 95% CI) but were maintained in ICE (0, p = 0.08). Further, moderate to large ES demonstrated an increase in scores in ICE between baseline and prior to exercise (d = 0.8, -0.19 to 1.73 95% CI), and a decline in scores after 27 min of exercise compared to prior to exercise (d = 0.69, -0.31 to 1.59 95% CI). However, S7 scores in ICE were not different between baseline and 27 min into exercise, suggesting that cognitive performance on this task was maintained over the exercise protocol (p > 0.05). At min 27, the average S7 score in CON was significantly lower than ICE (p = 0.01, d = 1.30, 0.19 to 2.20 95% CI; Table 5.1).

Similarly, OSPAN scores followed the same pattern as S7 scores. Baseline OSPAN scores were similar in both CON and ICE (65.1 ± 5.5, 65.0 ± 5.4, p > 0.05 respectively). Whilst scores in CON significantly declined over time (p = 0.03, d = 0.9, -0.08 to 1.74 95% CI), scores in ICE were observed to be maintained between baseline (65.0 ± 5.4) and min 30 (66.8 ± 4.2, p = 0.09). Further, scores for OSPAN were significantly lower in CON compared to ICE at the end of the exercise (p = 0.003, d = 0.78, 0.23 to 1.68 95% CI; Table 1).

Similar Tc values were observed at baseline for ICE and CON (37.00 ± 0.26°C, 36.93 ± 0.25°C, respectively, p > 0.05). Precooling led to a significant reduction in Tc as early as min 5 (ICE: 36.91 ± 0.25°C) into the ice ingestion compared to baseline (37 ± 0.26°C, p < 0.001, d = 0.35, -1.26 to 0.6 95% CI), with Tc further declining over the 30 min period of precooling (-0.67°C). At the end of precooling, Tc was significantly lower in ICE compared to CON (ICE: 36.33 ± 0.31°C, CON: 37.10 ± 0.11°C, p < 0.001, d = 3.31, 1.69 to 4.41 95% CI). Further, Tc remained significantly lower in ICE compared to CON at the end of exercise protocol (ICE: 38.07 ± 0.37°C; CON: 38.5 ± 0.22°C, p = 0.03, d = 1.41, 0.44 to 2.31 95% CI; Figure 1a).

Forehead temperature was similar at baseline between trials (CON: 35.39 ± 0.39°C, ICE: 35.52 ± 0.38°C, p = 0.86). ICE significantly reduced Th following precooling (min 30) compared to baseline (-0.59°C, p < 0.001, d = 1.53, 0.24 to 2.26 95% CI), with Th commencing to decline at the 15th min mark of the cooling protocol (ICE: 35.22 ± 0.42°C, CON: 35.68 ± 0.32°C, p = 0.02, d = 1.23, -0.14 to 2.13 95% CI) compared to CON. Meanwhile, Th significantly increased in CON (min 30) compared to baseline (+0.54°C, p < 0.01, d = 1.53, 0.38 to 2.45 95% CI) during the cooling/no-cooling protocol. Furthermore, Th was significantly lower at the start of the exercise in ICE compared to CON (min 0: -0.5°C, p = 0.004, d = 2.09, 0.81 to 3.04 95% CI), but was not different to CON from min 5 onwards into the exercise. Moderate to large ES suggested a tendency for Th to be lower for ICE compared to CON at every 5 min interval of the exercise protocol (p = 0.06-0.25, d = 0.66-1.09; Figure 1b).

Additionally, TS was significantly lower in ICE compared to CON at the beginning of exercise (min 0), and following precooling (p = 0.008, d = 1.57, 0.41 to 2.49 95% CI%; Table 2). While there was no main effect for trial (p = 0.78), mean TS increased progressively across the protocol, with this supported by main effect for time (p < 0.001), as well as large ES compared to baseline in both trials (CON: d = 7.7, 4.59 to 9.56 95% CI; ICE: d = 9.8, 5.95 to 12.15 95% CI).

DISCUSSION

This study examined the effect of crushed ice ingestion prior to exercise in hot, humid conditions on cognitive performance assessed prior to, during and after a repeated-sprint exercise. Results found that ice ingestion (7 g·kg-1) maintained working memory performance over the course of the protocol, as measured by S7 and OSPAN tests, with cognitive function declining in the control condition. Further, ice ingestion reduced Tc, Th and TS prior to exercise, with Tc remaining significantly lower throughout exercise compared to the control trial.

The current findings suggest that precooling via ice ingestion blunted the effect of heat on working memory, with similar scores found for cognitive performance between baseline and min 27 (S7) and min 30 (OSPAN) of exercise. It is noteworthy that when participants completed the final cognitive tests towards the end of exercise, Tc in CON was peaking at ~38.5°C, the stipulated threshold for cognitive deficits on some tasks (Hocking et al., 2001). Meanwhile in ICE, the highest Tc recorded during exercise was ~38.1°C. This may explain the preservation of cognitive performance in this trial, observed by constant test scores over the course of the protocol, despite exposure to heat and exercise. These results suggest that a Tc of ~38.1°C does not disturb cognitive function in respect to OSPAN and S7 performance. These findings are in agreement with previous studies, suggesting that cooling initially facilitates the preservation of cognitive performance by way of inducement and maintenance of a lower Tc (Racinais et al., 2008, Saldaris et al. 2020).

Saldaris et al. (2020) reported an improvement in working memory following crushed ice ingestion (7 g·kg-1) during and after 90 min of endurance exercise in the heat, compared to no-cooling, despite Tc peaking at ~38.7°C in both trials. Saldaris et al. (2020) also noted that Tc, TS and Th were significantly lower after ice ingestion, compared to no-cooling, with Th staying significantly lower 15 min into exercise. These researchers suggested that the reduction in Tc, Th, and TS, as a result of ice ingestion, may have allowed the athlete to focus more on the task in hand rather than the discomfort of the heat (Saldaris et al., 2020). In the current study, a reduction was observed in Tc (-0.67°C), Th (-0.59°C) and TS following ice ingestion, with associated cognitive benefits apparent. It is possible that a reduction in the combination of these variables, rather than Tc alone, may result in the maintenance of subsequent cognitive performance during exercise in the heat.

In regards to cooling methods, these can be classified as being either internal (the ingestion of crushed ice) or external (the wearing of cooling vests/ice packs/head cooling cap) strategies that cool the body either pre (prior), per (mid), or post-exercise (Best et al., 2018; Lee et al., 2014; Gaoua et al., 2011; Mazalan et al., 2022; Saldaris et al., 2020). In contrast to the results found in the current study in respect to ice ingestion (internal precooling), external precooling using a cooling cap was reported to reduce pre-exercise Th (-2.1°C) but not Tc prior to 60 min of running at 70% V̇O2peak in the heat (Mazalan et al., 2021). These researchers reported that this cooling effect diminished at the beginning of exercise with no benefit observed for subsequent cognitive performance (Mazalan et al., 2021). Similarly, the combination of external cooling devices (ice jacket and hand cooling gloves) prior to a cycling race simulation in the heat did not reduce Tc during exercise (Th not assessed) or have a benefit for subsequent cognitive performance (Maroni et al., 2019). Based on these findings, it can be suggested that internal precooling (via ice ingestion) may provide a greater cooling benefit on physiological and cognitive responses compared to external means (cooling devices). In this context, internal precooling may delay the drift in Tc and Th towards hyperthermia and subsequently act as a heat sink by allowing greater heat transfer via conduction, consequently reducing endogenous heat accumulation during exercise. Notably, ice changing its form from solid to liquid requires a great deal of heat absorption (Merrick et al., 2003). Therefore, an advantage of the internal heat loss that occurs as a result of ice ingestion lies in the efficiency of the heat transfer in the body. Notably, combining internal and external cooling methods has been shown to be more effective at lowering Tc than just utilising one cooling mode. For example, the reduction in Tc observed following cooling was greater in the study by Saldaris et al. (2020) (Tc: -0.80°C) compared to the current study (Tc: -0.67°C), most likely due to the cooling protocol being conducted in a cool room (~20°C) rather than an environmental chamber (~35°C). This suggests that the combination of internal cooling (ice ingestion) and external cooling (exposure to a cool room) prior to exercise could provide a greater heat sink by lowering Tc even further during the cooling protocol. Overall, these findings are of special interest for athletes who play sports where a deterioration in working memory in the heat could affect decision making under pressure whilst playing in an unpredictable game environment, such as team sports (Jiménez-Pavón, et al., 2011). Further, these findings are of relevance to sports event organisers, who may consider establishing a cooling station at events that provide crushed ice to athletes, which can be ingested prior to (or even during) exercise in the heat to preserve athletes’ subsequent physiological and cognitive performance.

Assessment of Th in this and other studies (Saldaris et al., 2019; 2020), represented an indirect assessment of brain temperature, with ice ingestion shown to reduce this variable. As noted earlier, this reduction in Th, was proposed to be due to conductive cooling resulting from the ingested ice cooling the blood in the carotid arteries, which then flowed to the brain (Onitsuka et al., 2018). This may result in the brain being better able to dissipate heat and hence blunt the exercise heat-induced rise in Th. In support of this, Onitsuka et al. (2018) reported a lower brain temperature (-0.4°C) associated with ice slushy ingestion (7.5 g·kg-1), as determined by magnetic resonance spectroscopy. The reduction in Th reported by these researchers over the cooling period was less than that found in the current study (Th -0.4°C versus Th -0.57°C), however, the cooling period used by Onitsuka et al. (2018) was shorter (15 min versus 30 min). This suggests that a longer cooling period in the current study facilitated a greater reduction in Th, which in turn may further benefit cognitive performance. While the use of magnetic resonance spectroscopy represents a better method for assessing brain temperature than measuring forehead temperature, this is not feasible during exercise, as it requires athletes to be in a supine position.

CONCLUSION

In conclusion, this study demonstrated that precooling with ice ingestion resulted in the maintenance of working memory, compared to no-cooling. This outcome was most likely a result of lower Tc and Th, and possibly TS that occurred after ice ingestion. This suggests that ice ingestion is an effective method that can reduce thermal strain, subsequently enhancing the brain’s ability to function during exposure to heat and exercise. Overall, these results demonstrate an effective and efficient strategy to preserve cognitive performance during exercise in hot and humid conditions.

ACKNOWLEDGEMENTS

The authors would like to express their gratitude to the participants for their commitment and interest. No potential conflict of interest was reported by the authors. This research was supported by The University of Western Australia. The experiments comply with the current laws of the country in which they were performed. The authors have no conflict of interest to declare. The datasets generated during and/or analyzed during the current study are not publicly available, but are available from the corresponding author who was an organizer of the study.

AUTHOR BIOGRAPHY

Journal of Sports Science and Medicine Nur Shakila Mazalan
Employment: Institute affiliation: School of Human Sciences (Exercise and Sports Science), The University of Western Australia, Crawley, WA, Australia
Degree: PhD
Research interests: Exercise physiology, thermoregulation and cognitive performance
E-mail: nurshakila.mazalan@research.uwa.edu.au
 

Journal of Sports Science and Medicine Grant Justin Landers
Employment: School of Human Sciences (Exercise and Sports Science), The University of Western Australia, Crawley, WA, Australia
Degree: Doctor / PhD
Research interests: Sport performance in different environments, kinanthropometry
E-mail: grant.landers@uwa.edu.au
 

Journal of Sports Science and Medicine Karen Elizabeth Wallman
Employment: School of Human Sciences (Exercise and Sports Science), The University of Western Australia, Crawley, WA, Australia
Degree: Associate Professor / PhD
Research interests: Chronic fatigue syndrome, exercise physiology and biochemistry, sport and physical activity and obesity
E-mail: Karen.wallman@uwa.edu.au
 

Journal of Sports Science and Medicine Ullrich Ecker
Employment: School of Psychological Science, The University of Western Australia, Crawley, WA, Australia
Degree: Associate Professor / PhD
Research interests: Human memory and reasoning
E-mail: ullrich.ecker@uwa.edu.au
 
 
REFERENCES
Journal of Sports Science and Medicine Bandelow S., Maughan R., Shirreffs S., Ozgünen K., Kurdak S., Ersöz G., Binnet M., Dvorak J. (2010) The effect of exercise, heat, cooling and rehydration strategies on cognitive function in football players. Scandinavian Journal of Medicine Science and Sports 20, 148-160.  Crossref
Journal of Sports Science and Medicine Bayliss D. M., Jarrold C., Gunn D. M., Baddeley A. D. (2003) The complexities of complex span: Explaining individual differences in working memory in children and adults. Journal of Experimental Psychology: General 132, 71-92.  Crossref
Journal of Sports Science and Medicine Best R., Payton S., Spears I., Riera F., Berger N. (2018) Topical and ingested cooling methodologies for endurance exercise performance in the heat. Sports 6, 11-.  Crossref
Journal of Sports Science and Medicine Brade C. J., Dawson B. T., Wallman K. E. (2013) Effect of pre-cooling on repeat-sprint performance in seasonally acclimatised males during an outdoor simulated team-sport protocol in warm conditions. Journal of Sports Science and Medicine 12, 565-570.  Pubmed
Journal of Sports Science and Medicine Bristow T., Jih C. S., Slabich A., Gunn J. (2016) Standardization and adult norms for the sequential tasks of serial 3’s and 7’s. Applied Neuropsychology: Adult 23, 372-378.  Crossref
Journal of Sports Science and Medicine Brown T. E. (1996) . Brown attention deficit disorder scales for adolescents and adults.
Journal of Sports Science and Medicine Cohen, J. (1988) Statistical power analysis for the behavioural sciences (2nd ed.) Hillsdale, NJ: Lawrence Erlbaum Associates.
Journal of Sports Science and Medicine Donnan K., Williams E. L., Stanger N. (2021) The effects of heat exposure during intermittent exercise on physical and cognitive performance among team sport athletes. Perceptual and Motor Skills 128, 439-466.  Crossref
Journal of Sports Science and Medicine Drust B., Rasmussen P., Mohr M., Nielsen B., Nybo L. (2005) Elevations in core and muscle temperature impairs repeated sprint performance. Acta Physiologica Scandinavica 183, 181-190.  Crossref
Journal of Sports Science and Medicine Duffield R., Marino F. E. (2007) Effects of pre-cooling procedures on intermittent-sprint exercise performance in warm conditions. European Journal of Applied Physiology 100, 727-735.  Crossref
Journal of Sports Science and Medicine Falkowska A., Gutowska I., Goschorska M., Nowacki P., Chlubek D., Baranowska-Bosiacka I. (2015) Energy metabolism of the brain, including the cooperation between astrocytes and neurons, especially in the context of glycogen metabolism. International Journal of Molecular Sciences 16, 25959-25981.  Crossref
Journal of Sports Science and Medicine Gaoua N., Racinais S., Grantham J., El Massioui F. (2011) Alterations in cognitive performance during passive hyperthermia are task dependent. International Journal of Hyperthermia 27, 1-9.  Crossref
Journal of Sports Science and Medicine Gerrett N., Jackson S., Yates J., Thomas G. (2017) Ice slurry ingestion does not enhance self-paced intermittent exercise in the heat. Scandinavian Journal of Medicine and Science in Sports 27, 1202-1212.  Crossref
Journal of Sports Science and Medicine Girard O., Brocherie F., Bishop D. J. (2015) Sprint performance under heat stress: A review. Scandinavian Journal of Medicine and Science in Sports 25, 79-89.  Crossref
Journal of Sports Science and Medicine Girard O., Mendez-Villanueva A., Bishop D. (2011) Repeated-sprint ability - Part I: factors contributing to fatigue. Sports Medicine (Auckland) 41, 673-694.  Crossref
Journal of Sports Science and Medicine Gonzalez-Alonso J., Teller C., Andersen S. L., Jensen F. B., Hyldig T., Nielsen B. (1999) Influence of body temperature on the development of fatigue during prolonged exercise in the heat. Journal of Applied Physiology 86, 1032-1039.  Crossref
Journal of Sports Science and Medicine Hayman M. (1942) Two-minute clinical test for measurement of intellectual impairment in psychiatric disorders. Archives of Neurology and Psychiatry 47, 454-464.  Crossref
Journal of Sports Science and Medicine Hocking C., Silberstein R. B., Lau W. M., Stough C., Roberts W. (2001) Evaluation of cognitive performance in the heat by functional brain imaging and psychometric testing. Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology 128, 719-734.  Crossref
Journal of Sports Science and Medicine Jiménez-Pavón D., Romeo J., Cervantes-Borunda M., Ortega F. B., Ruiz J. R., España-Romero V., Marcos A., Castillo M. J. (2011) Effects of a running bout in the heat on cognitive performance. Journal of Exercise Science and Fitness 9, 58-64.  Crossref
Journal of Sports Science and Medicine Kenefick R. W., Cheuvront S. N., Sawka M. N. (2007) Thermoregulatory function during the marathon. Sports Medicine 37, 312-315.  Crossref
Journal of Sports Science and Medicine Knochel, J. P. and Reed, G. (1994) Disorders of heat regulation. In: Narins RG, ed. Maxwell & Kleeman's clinical disorders of fluid and electrolyte metabolism. 5th ed. New York: McGraw-Hill, 15, 49-90.
Journal of Sports Science and Medicine Lee J. K., Koh A. C., Koh S. X., Liu G. J., Nio A. Q., Fan P. W. (2014) Neck cooling and cognitive performance following exercise-induced hyperthermia. European Journal of Applied Physiology 114, 375-384.  Crossref
Journal of Sports Science and Medicine Maroni T., Dawson B., Dennis M., Naylor L., Brade C., Wallman K. (2018) Effects of half-time cooling using a cooling glove and jacket on manual dexterity and repeated-sprint performance in heat. Journal of Sports Science and Medicine 17, 485-491.  Crossref
Journal of Sports Science and Medicine Maroni T., Dawson B., Landers G., Naylor L., Wallman K. (2019) Hand and torso pre-cooling does not enhance subsequent high intensity cycling or cognitive performance in heat. Temperature 7, 165-177.  Crossref
Journal of Sports Science and Medicine Mazalan N. S., Landers G. J., Wallman K. E., Ecker U. (2021) Head cooling prior to exercise in the heat does not improve cognitive performance. Journal of Sports Science and Medicine 20, 69-76.  Crossref
Journal of Sports Science and Medicine Mazalan N. S., Landers G. J., Wallman K. E., Ecker U. (2022) A combination of ice ingestion and head cooling enhances cognitive performance during endurance exercise in the heat. Journal of Sports Science and Medicine 21, 23-32.  Crossref
Journal of Sports Science and Medicine Merrick M. A., Jutte L. S., Smith M. E. (2003) Cold modalities with different thermo-dynamic properties produce different surface and intramuscular temperatures. Journal of Athletic Training 38, 28-33.  Crossref
Journal of Sports Science and Medicine Minett G. M., Duffield R., Marino F. E., Portus M. (2011) Volume-dependent response of precooling for intermittent-sprint exercise in the heat. Medicine and Science in Sports and Exercise 43, 1760-1769.  Crossref
Journal of Sports Science and Medicine Minett G. M., Duffield R., Marino F. E., Portus M. (2012) Duration-dependant response of mixed-method pre-cooling for intermittent-sprint exercise in the heat. European Journal of Applied Physiology 112, 3655-3666.  Crossref
Journal of Sports Science and Medicine Nassis G. P., Brito J., Dvorak J., Chalabi H., Racinais S. (2015) The association of environmental heat stress with performance: Analysis of the 2014 FIFA World Cup Brazil. British Journal of Sports Medicine 49, 609-613.  Crossref
Journal of Sports Science and Medicine Nybo L., Moller K., Volianitis S., Nielsen B., Secher N. H. (2002) Effects of hyperthermia on cerebral blood flow and metabolism during prolonged exercise in humans. Journal of Applied Physiology 93, 58-64.  Crossref
Journal of Sports Science and Medicine Nybo L., Nielsen B. (2001) Hyperthermia and central fatigue during prolonged exercise in humans. Journal of Applied Physiology 91, 1055-1060.  Crossref
Journal of Sports Science and Medicine Onitsuka S., Nakamura D., Onishi T., Arimitsu T., Takahashi H., Hasegawa H. (2018) Ice slurry ingestion reduces human brain temperature measured using non-invasive magnetic resonance spectroscopy. Scientific Reports 8, 2757.  Crossref
Journal of Sports Science and Medicine Periard J. D., Eijsvogels T. M., Daanen H. A. M. (2021) Exercise under heat stress: thermoregulation, hydration, performance implications, and mitigation strategies. Physiological Revision 101, 1873-1979.  Crossref
Journal of Sports Science and Medicine Racinais S., Gaoua N., Grantham J. (2008) Hyperthermia impairs short-term memory and peripheral motor drive transmission. Journal of Physiology 586, 4751-4762.  Crossref
Journal of Sports Science and Medicine Racinais S., Moussay S., Nichols D., Travers G., Belfekih T., Schumacher Y. O., Periard J. D. (2019) Core temperature up to 41.5ºC during the UCI Road Cycling World Championships in the heat. British Journal of Sports Medicine 53, 426-429.  Crossref
Journal of Sports Science and Medicine Saldaris J. M., Landers G. J., Lay B. S. (2020) Enhanced decision making and working memory during exercise in the heat with crushed ice ingestion. International Journal of Sports Physiology and Performance 15, 503-510.  Crossref
Journal of Sports Science and Medicine Saldaris J. M., Landers G. J., Lay B. S., Zimmermann M. R. (2019) Internal precooling decreases forehead and core temperature but does not alter choice reaction time during steady state exercise in hot, humid conditions. Journal of Thermal Biology 81, 66-72.  Crossref
Journal of Sports Science and Medicine Schmit C., Hausswirth C., Le Meur Y., Duffield R. (2017) Cognitive functioning and heat strain: performance responses and protective strategies. Sports Medicine (Auckland) 47, 1289-1302.  Crossref
Journal of Sports Science and Medicine Schulze E., Daanen H. A., Levels K., Casadio J. R., Plews D. J., Kilding A. E., Siegel R., Laursen P. B. (2015) Effect of thermal state and thermal comfort on cycling performance in the heat. International Journal of Sports Physiology and Performance 10, 655-663.  Crossref
Journal of Sports Science and Medicine Smits B. L. M., Pepping G. J., Hettinga F. J. (2014) Pacing and decision making in sport and exercise: The roles of perception and action in the regulation of exercise intensity. Sports Medicine (Auckland) 44, 763-775.  Crossref
Journal of Sports Science and Medicine Sunderland C., Nevill M. E. (2005) High-intensity intermittent running and field hockey skill performance in the heat. Journal of Sports Sciences 23, 531-540.  Crossref
Journal of Sports Science and Medicine Turner M. L., Engle R. W. (1989) Is working memory capacity task dependent?. Journal of Memory and Language 28, 127-154.  Crossref
Journal of Sports Science and Medicine Unsworth N., Heitz R. P., Schrock J. C., Engle R. W. (2005) An automated version of the operation span task. Behavior Research Methods 37, 498-505.  Crossref
Journal of Sports Science and Medicine Young A. J., Sawka M. N., Epstein Y., Decristofano B., Pandolf K. B. (1987) Cooling different body surfaces during upper and lower body exercise. Journal of Applied Physiology 63, 1218-1223.  Crossref
Journal of Sports Science and Medicine Zimmermann M., Landers G., Wallman K.E., Saldaris J. (2017) The effects of crushed ice ingestion prior to steady state exercise in the heat. International Journal of Sport Nutrition and Exercise Metabolism 27, 220-227.  Crossref
 
 
 
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