Effect of a cooling strategy combining forearm water immersion and a low dose of ice slurry ingestion on physiological response and subsequent exercise performance in the heat

Nakamura, Daisuke; Muraishi, Koji; Hasegawa, Hiroshi; Yasumatsu, Mikinobu; Takahashi, Hideyuki

doi:10.1016/j.jtherbio.2020.102530

Cited by 14 publications

(10 citation statements)

References 31 publications

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“…Additionally, further analysis showed differences in the relative risks ( Table 4 ), which implies the difference in risk when there is a one unit increase in WBGT max . From these notions, to reduce the occurrence of heat illness, it is important: to set an optimal hazard or warning system that matches the actual occurrence of heat illness; to ensure that heat-related information is always up-to-date and accessible via, for example, the internet or a community information transportation tool; and to use this information for developing and implementing heat illness action plans, such as promoting the use of air conditioning, hydration, and measures to avoid an excessive increase in core temperatures [ 30 ] (e.g., to reduce heat illness). Nonetheless, in the month of June in Japan, it would likely be better for the hazard levels to be set to lower temperatures because the factors that influence the occurrence of heat illnesses are complex; such lowering of the threshold could make the heat warning system more effective.…”

Section: Discussionmentioning

confidence: 99%

Trends in ambulance dispatches related to heat illness from 2010 to 2019: An ecological study

Nakamura

Kinoshita²,

Asada³

et al. 2022

PLoS ONE

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Heatstroke is a serious heat-related illness that can even cause death. Heat alert systems play an important role in reducing the number of patients experiencing heat illness, as they encourage preventive actions such as the use of air conditioning, hydration, or other strategies. However, to date, the Japanese hazard classification has not considered seasonal and regional variations, despite clear differences in meteorological conditions across different regions in Japan. Moreover, several studies have reported a difference in thermoregulation between older and younger adults, implying that the hazard classification should also consider age differences. This study examined the relationship between the number of ambulance dispatches related to heat illness (ADRHI) and the Japanese heat hazard classification from 2010 to 2019, focusing on monthly and regional differences. Data from 47 prefectures during the 10-year period were collected and analyzed. ADRHI and wet bulb globe temperature (WBGT) data were collected from Japan’s Ministry of Internal Affairs and Communications and the Ministry of the Environment Heat Illness Prevention Information website, respectively. The findings showed a significant relationship between ADRHI and WBGTmax (p < 0.05, r = 0.74). ADRHI per 100,000 people showed significant differences across months. The post hoc test detected the first steep increase in ADRHI at a WBGTmax of 23°C than at 22°C in June, and at a WBGTmax of 26°C, 27°C, and 25°C in July, August, and September, respectively. Moreover, the first significant increase in ADRHI per 100,000 people at WBGTmax differed across each region, at a WBGTmax of 24°C in Hokkaido-Tohoku, 25°C in Kanto, Kansai, and Chugoku, 26°C in Chubu, 27°C in Shikoku, and 28°C in Kyushu-Okinawa. Further, Poisson regression analysis revealed that the relative risks differed across each region and month. These results imply that the hazard classification should be adjusted according to region and month in Japan.

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Section: Discussionmentioning

confidence: 99%

Trends in ambulance dispatches related to heat illness from 2010 to 2019: An ecological study

Nakamura

Kinoshita²,

Asada³

et al. 2022

PLoS ONE

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“…We can conclude that studies showing no differences in end-exercise physiological outcomes with higher exercise intensity or duration support the positive effects of the internal cooling intervention on physiological parameters. In contrast, findings of increased core temperature at exhaustion following internal physical cooling are likely due to higher intensity or longer exercise duration in the trial Nakamura et al, 2020). When interpreting the impact of internal cooling on physiological or perceptional outcomes, it is therefore always crucial to take into account the time course and their relationship with exercise intensity and performance.…”

Section: Figure 10mentioning

confidence: 99%

Effects of internal cooling on physical performance, physiological and perceptional parameters when exercising in the heat: A systematic review with meta-analyses

et al. 2023

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Background: An elevated core temperature (Tcore) increases the risk of performance impairments and heat-related illness. Internal cooling (IC) has the potential to lower Tcore when exercising in the heat. The aim of the review was to systematically analyze the effects of IC on performance, physiological, and perceptional parameters.Methods: A systematic literature search was performed in the PubMed database on 17 December 2021. Intervention studies were included assessing the effects of IC on performance, physiological, or perceptional outcomes. Data extraction and quality assessment were conducted for the included literature. The standardized mean differences (SMD) and 95% Confidence Intervals (CI) were calculated using the inverse-variance method and a random-effects model.Results: 47 intervention studies involving 486 active subjects (13.7% female; mean age 20–42 years) were included in the meta-analysis. IC resulted in significant positive effects on time to exhaustion [SMD (95% CI) 0.40 (0.13; 0.67), p < 0.01]. IC significantly reduced Tcore [−0.19 (22120.34; −0.05), p < 0.05], sweat rate [−0.20 (−0.34; −0.06), p < 0.01], thermal sensation [−0.17 (−0.33; −0.01), p < 0.05], whereas no effects were found on skin temperature, blood lactate, and thermal comfort (p > 0.05). IC resulted in a borderline significant reduction in time trial performance [0.31 (−0.60; −0.02), p = 0.06], heart rate [−0.13 (−0.27; 0.01), p = 0.06], rate of perceived exertion [−0.16 (−0.31; −0.00), p = 0.05] and borderline increased mean power output [0.22 (0.00; 0.44), p = 0.05].Discussion: IC has the potential to affect endurance performance and selected physiological and perceptional parameters positively. However, its effectiveness depends on the method used and the time point of administration. Future research should confirm the laboratory-based results in the field setting and involve non-endurance activities and female athletes.Systematic review registration:https://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42022336623.

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“…Regarding the provision of information, a guidebook on heat countermeasures (Japan Institute of Sports Sciences, 2017 ) was published, and workshops were held in 2018 and 2019 to share up-to-date knowledge and global trends for athletes and coaches at JISS. To address the second issue, we validated the forearm cooling method and reported that a combination of forearm cooling and ice slurry ingestion resulted in a faster drop in the core temperature raised by exercise (Nakamura et al, 2020 ), and proposed this as a new effective and easy cooling method. Ice slurry ingestion was also found to promote a decrease in core temperature during post-exercise recovery (Nakamura et al, 2021 ) and decrease in brain temperature measured by non-invasive magnetic resonance spectroscopy at rest without exercise intervention (Onitsuka et al, 2018 ).…”

Section: The Heat Countermeasures Projectmentioning

confidence: 99%

Case Report: Countermeasures Against Heat and Coronavirus for Japanese Athletes at the Tokyo 2020 Olympics and Paralympic Games

Nakamura

Naito²,

Saito³

et al. 2022

Front. Sports Act. Living

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The Tokyo 2020 Olympics and Paralympic Games were held in the hottest environment in the history of the games. Additionally, the worldwide coronavirus disease 2019 (COVID-19) pandemic necessitated daily polymerase chain reaction (PCR) testing during the games, wearing a mask became mandatory publicly, and it was an unheard and unique Olympic with no spectators. Heat acclimation, hydration, and body cooling are essential for safe and high-performance activities in hot environments. In 2015, the Japan Institute of Sports Sciences launched the “Heat Countermeasure Project” to conduct experiments and practical research on heat countermeasures and investigate issues related to heat countermeasures in each athletic event. The results obtained were proposed to various Japan national sports teams, and support for heat countermeasures for the Tokyo 2020 games was promoted in consultation with national federations. Furthermore, due to the COVID-19 pandemic, infectious disease countermeasures for the Tokyo 2020 Games during support were a must. Moreover, athletes, coaches, and team staff could not avoid implementing heat countermeasures while adopting measures against infectious diseases. This study aimed to clarify the issues faced with heat countermeasures and report on heat acclimation training and cooling support efforts, considering measures against infectious diseases.

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Effect of a cooling strategy combining forearm water immersion and a low dose of ice slurry ingestion on physiological response and subsequent exercise performance in the heat

Cited by 14 publications

References 31 publications

Trends in ambulance dispatches related to heat illness from 2010 to 2019: An ecological study

Trends in ambulance dispatches related to heat illness from 2010 to 2019: An ecological study

Effects of internal cooling on physical performance, physiological and perceptional parameters when exercising in the heat: A systematic review with meta-analyses

Case Report: Countermeasures Against Heat and Coronavirus for Japanese Athletes at the Tokyo 2020 Olympics and Paralympic Games

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