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Notley SR, Mitchell D, Taylor NAS. A century of exercise physiology: concepts that ignited the study of human thermoregulation. Part 4: evolution, thermal adaptation and unsupported theories of thermoregulation. Eur J Appl Physiol 2024; 124:147-218. [PMID: 37796290 DOI: 10.1007/s00421-023-05262-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 06/13/2023] [Indexed: 10/06/2023]
Abstract
This review is the final contribution to a four-part, historical series on human exercise physiology in thermally stressful conditions. The series opened with reminders of the principles governing heat exchange and an overview of our contemporary understanding of thermoregulation (Part 1). We then reviewed the development of physiological measurements (Part 2) used to reveal the autonomic processes at work during heat and cold stresses. Next, we re-examined thermal-stress tolerance and intolerance, and critiqued the indices of thermal stress and strain (Part 3). Herein, we describe the evolutionary steps that endowed humans with a unique potential to tolerate endurance activity in the heat, and we examine how those attributes can be enhanced during thermal adaptation. The first of our ancestors to qualify as an athlete was Homo erectus, who were hairless, sweating specialists with eccrine sweat glands covering almost their entire body surface. Homo sapiens were skilful behavioural thermoregulators, which preserved their resource-wasteful, autonomic thermoeffectors (shivering and sweating) for more stressful encounters. Following emigration, they regularly experienced heat and cold stress, to which they acclimatised and developed less powerful (habituated) effector responses when those stresses were re-encountered. We critique hypotheses that linked thermoregulatory differences to ancestry. By exploring short-term heat and cold acclimation, we reveal sweat hypersecretion and powerful shivering to be protective, transitional stages en route to more complete thermal adaptation (habituation). To conclude this historical series, we examine some of the concepts and hypotheses of thermoregulation during exercise that did not withstand the tests of time.
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Affiliation(s)
- Sean R Notley
- Defence Science and Technology Group, Department of Defence, Melbourne, Australia
- School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Duncan Mitchell
- Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa
- School of Human Sciences, University of Western Australia, Crawley, Australia
| | - Nigel A S Taylor
- Research Institute of Human Ecology, College of Human Ecology, Seoul National University, Seoul, Republic of Korea.
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Donnan KJ, Williams EL, Bargh MJ. The effectiveness of heat preparation and alleviation strategies for cognitive performance: A systematic review. Temperature (Austin) 2023; 10:404-433. [PMID: 38130656 PMCID: PMC10732620 DOI: 10.1080/23328940.2022.2157645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 12/01/2022] [Indexed: 12/15/2022] Open
Abstract
A range of occupational and performance contexts (e.g. military personnel operations, emergency services, sport) require the critical maintenance of cognitive performance in environmentally challenging environments. Several reviews exist which evaluate the effectiveness of heat preparation strategies to facilitate physical performance. To date, no review has explored the usefulness of heat preparation strategies for cognitive performance. Therefore, this systematic review aimed to evaluate a range of interventions for the maintenance of cognitive performance, during or following active or passive heat exposure. Studies to be included were assessed by two authors reviewing title, abstract, and full-text. Forty articles were identified which met the inclusion criteria. Interventions were categorised into chronic (i.e. acclimation/acclimatisation) and acute strategies (i.e. hydration, cooling, supplementation, psychological). The results indicate that medium-term consecutive heat acclimation may mitigate some cognitive deficits under heat stress, although heat acclimation effectiveness could be influenced by age. Further, pre-cooling appears the most effective cooling method for maintaining cognitive performance under heat stress, although results were somewhat ambiguous. The hydration literature showed that the most effective hydration strategies were those which individualised electrolyte fortified fluid volumes to match for sweat loss. Limited research exploring psychological interventions indicates that motivational self-talk could be facilitative for maintaining cognitive skills following exercise in hot conditions. These findings can be used to help inform strategies for maintaining critical cognitive and decision-making skills in hot environments.
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Affiliation(s)
- Kate J. Donnan
- Department of Sport, Exercise, and Rehabilitation Sciences, University of Hull, Hull, HU6 7RX, UK
| | - Emily L. Williams
- Centre for Human Performance, Carnegie School of Sport, Leeds Beckett University, Leeds, LS6 3QS, UK
| | - Melissa J. Bargh
- School of Sport and Exercise Science, College of Social Science of University of Lincoln, Lincoln, LN6 7TS, UK
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Tochihara Y, Wakabayashi H, Lee JY, Wijayanto T, Hashiguchi N, Saat M. How humans adapt to hot climates learned from the recent research on tropical indigenes. J Physiol Anthropol 2022; 41:27. [PMID: 35836266 PMCID: PMC9281079 DOI: 10.1186/s40101-022-00302-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Accepted: 07/03/2022] [Indexed: 11/10/2022] Open
Abstract
AbstractThis review mainly aimed to introduce the findings of research projects comparing the responses of tropical and temperate indigenes to heat. From a questionnaire survey on thermal sensation and comfort of Indonesians and Japanese, we found that the thermal descriptor “cool” in tropical indigenes connotes a thermally comfortable feeling, suggesting that linguistic heat acclimatization exists on a cognitive level. Ten male students born and raised in Malaysia were invited to Fukuoka, Japan, and compared their responses with 10 Japanese male students with matched physical fitness and morphological characteristics. Cutaneous thermal sensitivity: The sensitivities were measured at 28 °C. The forehead warm sensitivity was significantly blunted in Malaysians. The less sensitivity to the warmth of tropical indigenes is advantageous in respect to withstanding heat stress with less discomfort and a greater ability to work in hot climates. Passive heat stress: Thermoregulatory responses, especially sweating, were investigated, during the lower leg hot bathing (42 °C for 60 min). The rectal temperature at rest was higher in Malaysians and increased smaller during immersion. There was no significant difference in the total amount of sweating between the two groups, while the local sweating on the forehead and thighs was lesser in Malaysians, suggesting distribution of sweating was different from Japanese. Exercise: Malaysian showed a significantly smaller increase in their rectal temperature during 55% maximal exercise for 60 min in heat (32 °C 70% relative humidity), even with a similar sweating and skin blood flow response in Japanese. The better heat tolerance in Malaysians could be explained by the greater convective heat transfer from the body core to the skin due to the greater core-to-skin temperature gradient. In addition, when they were hydrated, Malaysian participants showed better body fluid regulation with smaller reduction in plasma volume at the end of the exercise compared to the non-hydrated condition, whereas Japanese showed no difference between hydration conditions. We further investigated the de-acclimatization of heat adaptation by longitudinal observation on the heat tolerance of international students who had moved from tropical areas to Fukuoka for several years.
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Shourav MK, Salsabila S, Lee JY, Kim JK. Estimation of core body temperature by near-infrared imaging of vein diameter change in the dorsal hand. BIOMEDICAL OPTICS EXPRESS 2021; 12:4700-4712. [PMID: 34513219 PMCID: PMC8407806 DOI: 10.1364/boe.431534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/29/2021] [Accepted: 06/30/2021] [Indexed: 05/21/2023]
Abstract
Core body temperature (Tcore ) is a key indicator of personal thermal comfort and serves as a monitor of thermal strain. Multi-parametric sensors are not practical for estimating core temperature because they require long data collection times and a wide variety of settings. This study introduces dorsal hand vein dynamics as a novel indicator along with heart rate (HR) and dorsal hand skin temperature (Thand ) for predicting Tcore during rest following Tcore elevation. Twelve healthy males aged 27 ± 9 years old participated in the experiment. The experimental procedure consisted of a 10-min rest followed by 60 min of passive heat stress induced by leg immersion in hot water at 42°C and a 40-min thermal relaxation period after the legs were removed from the water. A near-infrared (NIR) imaging system was configured to monitor the dorsal hand veins during the entire experimental session. The values of HR, Thand , and Tcore were continuously monitored while the ambient temperature and relative humidity (RH) were maintained in a climate chamber at 20°C and 50%, respectively. Our selected predictor parameters demonstrated similar patterns in the Tcore such that the value increased as a result of passive heat stress and decreased in the thermal relaxation phase. The experimental data were divided into two phases: thermal stress and relaxation. At the resting condition, inclusion of the hand vein diameter (VD) improved the multiple linear regression value (R2 ) about 26%. At the relaxation phase, however, training regressions R2 = 0.68 and R2 = 0.94 were observed in the regression model with and without considering VD, respectively. The test regression value of R2 = 0.88 and the root mean square error (RMSE) of 0.18°C showed good agreement with the predicted values. These findings demonstrate acceptable validity of the non-invasive Tcore estimation at the resting condition. In particular, the inclusion of VD as a predictor in the regression analysis increases the prediction accuracy with a lower RMSE value.
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Affiliation(s)
- Mohiuddin Khan Shourav
- Department of Mechanical Engineering, Graduate School, Kookmin University, Seoul 02707, Republic of Korea
- Currently with the Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Syifa Salsabila
- Department of Textiles, Merchandising and Fashion Design, College of Human Ecology, Seoul National University, Seoul 08826, Republic of Korea
| | - Joo-Young Lee
- Department of Textiles, Merchandising and Fashion Design, College of Human Ecology, Seoul National University, Seoul 08826, Republic of Korea
| | - Jung Kyung Kim
- School of Mechanical Engineering and Department of Integrative Biomedical Science and Engineering, Graduate School, Kookmin University, Seoul 02707, Republic of Korea
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Taylor NAS, Lee JY, Kim S, Notley SR. Physiological interactions with personal-protective clothing, physically demanding work and global warming: An Asia-Pacific perspective. J Therm Biol 2021; 97:102858. [PMID: 33863427 DOI: 10.1016/j.jtherbio.2021.102858] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/07/2021] [Accepted: 01/13/2021] [Indexed: 01/03/2023]
Abstract
The Asia-Pacific contains over half of the world's population, 21 countries have a Gross Domestic Product <25% of the world's largest economy, many countries have tropical climates and all suffer the impact of global warming. That 'perfect storm' exacerbates the risk of occupational heat illness, yet first responders must perform physically demanding work wearing personal-protective clothing and equipment. Unfortunately, the Eurocentric emphasis of past research has sometimes reduced its applicability to other ethnic groups. To redress that imbalance, relevant contemporary research has been reviewed, to which has been added information applicable to people of Asian, Melanesian and Polynesian ancestry. An epidemiological triad is used to identify the causal agents and host factors of work intolerance within hot-humid climates, commencing with the size dependency of resting metabolism and heat production accompanying load carriage, followed by a progression from the impact of single-layered clothing through to encapsulating ensembles. A morphological hypothesis is presented to account for inter-individual differences in heat production and heat loss, which seems to explain apparent ethnic- and gender-related differences in thermoregulation, at least within thermally compensable states. The mechanisms underlying work intolerance, cardiovascular insufficiency and heat illness are reviewed, along with epidemiological data from the Asia-Pacific. Finally, evidence-based preventative and treatment strategies are presented and updated concerning moisture-management fabrics and barriers, dehydration, pre- and post-exercise cooling, and heat adaptation. An extensive reference list is provided, with >25 recommendations enabling physiologists, occupational health specialists, policy makers, purchasing officers and manufacturers to rapidly extract interpretative outcomes pertinent to the Asia-Pacific.
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Affiliation(s)
- Nigel A S Taylor
- Research Institute of Human Ecology, College of Human Ecology, Seoul National University, Seoul, Republic of Korea.
| | - Joo-Young Lee
- Research Institute of Human Ecology, College of Human Ecology, Seoul National University, Seoul, Republic of Korea
| | - Siyeon Kim
- Human Convergence Technology R&D Department, Korea Institute of Industrial Technology, Ansan, Republic of Korea
| | - Sean R Notley
- School of Human Kinetics, University of Ottawa, Ottawa, Canada
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Ko Y, Kang J, Seol SH, Lee JY. Effectiveness of skin-heating using a water-perfused suit as passive and post-exercise heat acclimation strategies. J Therm Biol 2020; 93:102703. [PMID: 33077124 DOI: 10.1016/j.jtherbio.2020.102703] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 08/14/2020] [Accepted: 08/15/2020] [Indexed: 11/26/2022]
Abstract
The purpose of the present study was to evaluate the effectiveness of passive and post-exercise heat acclimation strategies through directly heating the skin with a water-perfused suit. Nineteen young males participated in the heat acclimation (HA) protocols for 10 days, which were conducted at an air temperature of 33oC with 60%RH. The exercise-only condition (N = 6) conducted 1-h treadmill walking (6 km·h-1) followed by 1-h rest. The post-exercise passive-heating condition (N = 6) wore the suit (inflow water temperature 44.2oC) for 1-h after 1-h walking. The passive-heating condition (N = 7) donned the suit for 2 h. Heat tolerance tests (leg immersion in 42oC water for 60 min) were conducted before and after the training to evaluate changes due to the 10-day intervention. Reflecting that suit-wearing for 10 days as both passive and post-exercise HA strategies can effectively induce adaptive changes, significant interaction effects appeared in: increase or decrease in mean skin temperature (P < 0.05) and elevation in whole-body sweat rate (P < 0.05). Reduction in rectal temperature (P < 0.05) and blood pressure (P < 0.05) were found most prominently in the passive-heating condition. These results indicate that this new method of heat acclimation training, donning a skin-heating water-perfused suit, can generate thermoregulatory benefits. The passive HA intervention could be applied to individuals for whom doing exercise regularly are not feasible.
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Affiliation(s)
- Yelin Ko
- College of Human Ecology, Seoul National University, South Korea
| | - Juho Kang
- College of Human Ecology, Seoul National University, South Korea; Department of Physical Education, Seoul National University, South Korea
| | - Seon-Hong Seol
- College of Human Ecology, Seoul National University, South Korea
| | - Joo-Young Lee
- College of Human Ecology, Seoul National University, South Korea; Research Institute of Human Ecology, Seoul National University, South Korea.
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Burtscher M, Gatterer H, Burtscher J, Mairbäurl H. Extreme Terrestrial Environments: Life in Thermal Stress and Hypoxia. A Narrative Review. Front Physiol 2018; 9:572. [PMID: 29867589 PMCID: PMC5964295 DOI: 10.3389/fphys.2018.00572] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 04/30/2018] [Indexed: 12/22/2022] Open
Abstract
Living, working and exercising in extreme terrestrial environments are challenging tasks even for healthy humans of the modern new age. The issue is not just survival in remote environments but rather the achievement of optimal performance in everyday life, occupation, and sports. Various adaptive biological processes can take place to cope with the specific stressors of extreme terrestrial environments like cold, heat, and hypoxia (high altitude). This review provides an overview of the physiological and morphological aspects of adaptive responses in these environmental stressors at the level of organs, tissues, and cells. Furthermore, adjustments existing in native people living in such extreme conditions on the earth as well as acute adaptive responses in newcomers are discussed. These insights into general adaptability of humans are complemented by outcomes of specific acclimatization/acclimation studies adding important information how to cope appropriately with extreme environmental temperatures and hypoxia.
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Affiliation(s)
- Martin Burtscher
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria.,Austrian Society for Alpine and Mountain Medicine, Innsbruck, Austria
| | - Hannes Gatterer
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria.,Institute of Mountain Emergency Medicine, EURAC Research, Bolzano, Italy
| | - Johannes Burtscher
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Heimo Mairbäurl
- Medical Clinic VII, Sports Medicine, University Hospital Heidelberg, Heidelberg, Germany.,German Center for Lung Research (DZL/TLRC-H), Heidelberg, Germany
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Fdez-Arroyabe P, Robau DT. Past, present and future of the climate and human health commission. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2017; 61:115-125. [PMID: 28735444 DOI: 10.1007/s00484-017-1413-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 07/12/2017] [Accepted: 07/12/2017] [Indexed: 06/07/2023]
Abstract
The following paper presents the history of the Climate and Human Health Commission at the International Society of Biometeorology after more than one decade since its creation. A brief history of the origins of the human biometeorology is revealed through some of the main research topics and publications of the founders of the society in this field. Secondly, it is presented as a brief review of the activities of the commission in the last 10 years, based on the reports that have periodically been submitted by members of the commission to the Bulletin of the society. A summary of the topics of interest on human biometeorology and the most frequent research topics are also described. Thirdly, the need of adapting human biometeorology contents, methods and techniques to a changing world is articulated according to some of the new environmental threats in the XXI century. Finally, a list of future actions and research lines collected through a form from members of the commission is presented. The paper concludes with the existence of great challenge for human biometeorology in order to transform biometeorological knowledge into specific services to improve the wellbeing of human beings.
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Affiliation(s)
- Pablo Fdez-Arroyabe
- Geography Department, Geobiomet Research Group, University of Cantabria, Santander, Cantabria, Spain.
| | - Daysarih Tápanes Robau
- Geography Department, Geobiomet Research Group, University of Cantabria, Santander, Cantabria, Spain
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Wijayanto T, Toramoto S, Maeda Y, Son SY, Umezaki S, Tochihara Y. Cognitive performance during passive heat exposure in Japanese males and tropical Asian males from Southeast Asian living in Japan. J Physiol Anthropol 2017; 36:8. [PMID: 28057082 PMCID: PMC5217342 DOI: 10.1186/s40101-016-0124-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 12/08/2016] [Indexed: 11/22/2022] Open
Abstract
Background Heat acclimatization studies have reported that tropical natives have better physiological function to tolerate heat exposure compared to those from temperate natives, in which may result in a better ability to show a better resistance to performance losses during heat stress. In this study, we investigate whether the degree of heat acclimatization affects cognitive abilities during heat exposure by comparing heat acclimatization level of subjects from Southeast Asia and temperate natives from Japan. Methods Eleven tropical males from Southeast Asia and ten temperate males from Japan participated in this study and performed two types of cognitive task: short-term memory test and mental arithmetic test, under control and passive heat exposure conditions. Passive heat condition was stimulated through leg immersion protocol by immersing subjects’ lower legs into a hot water maintained at 42 °C in a chamber controlled at 28 °C air temperature and 50% relative humidity. Results The results show that the subjects in tropical group, who had smaller increase of rectal temperature, did not show any performance losses in both cognitive tests during heat exposure, while for Japanese group, there was performance decrement in mental arithmetic test during heat exposure (P < 0.05). We also found that the subjects in both tropical and Japanese groups tried to maintain their performance by increasing oxyhemoglobin in their prefrontal cortex area during performing the tasks during heat exposure. In addition, the subjects in the Japanese group showed higher increase of oxyhemoglobin when they performed the tasks during heat exposure than those when they performed the tasks in control condition (P < 0.05), while the subjects in tropical group did not show any differences in oxyhemoglobin during task performance between control and heating conditions. Conclusions In addition to a better ability to maintain their homeostasis during heat exposure, tropical natives from Southeast Asia showed better resistance to performance loss during heat exposure in comparison with temperate natives from Japan. The tropical natives also showed smaller increase of oxyhemoglobin indicating less cognitive effort to maintain performance.
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Affiliation(s)
- Titis Wijayanto
- Industrial Engineering Program, Faculty of Engineering, Universitas Gadjah Mada, Jl Grafika 2 Kampus UGM, Yogyakarta, 55281, Indonesia. .,Department of Human Science, Kyushu University, 4-9-1, Shiobaru, Minami-ku, Fukuoka, 815-8540, Japan.
| | - Sayo Toramoto
- Department of Human Science, Kyushu University, 4-9-1, Shiobaru, Minami-ku, Fukuoka, 815-8540, Japan
| | - Yasuhiko Maeda
- Department of Human Science, Kyushu University, 4-9-1, Shiobaru, Minami-ku, Fukuoka, 815-8540, Japan
| | - Su-Young Son
- National Institute of Occupational Safety and Health Japan, 6-2-1 Nagao, Tama-ku, Kawasaki, 214-8585, Japan
| | - Sonomi Umezaki
- Faculty of Fukuoka Medical Technology, Teikyo University, 4-3-124 Shinkatsudachimachi, Omuta, 836-8505, Japan
| | - Yutaka Tochihara
- Department of Human Science, Kyushu University, 4-9-1, Shiobaru, Minami-ku, Fukuoka, 815-8540, Japan
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Khatun A, Ashikaga S, Nagano H, Hasib MA, Taimura A. Cold-induced vasodilation comparison between Bangladeshi and Japanese natives. J Physiol Anthropol 2016; 35:13. [PMID: 27141944 PMCID: PMC4855807 DOI: 10.1186/s40101-016-0095-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 04/29/2016] [Indexed: 11/20/2022] Open
Abstract
Background The human thermoregulation system responds to changes in environmental temperature, so humans can self-adapt to a wide range of climates. People from tropical and temperate areas have different cold tolerance. This study compared the tolerance of Bangladeshi (tropical) and Japanese (temperate) people to local cold exposure on cold-induced vasodilation (CIVD). Methods Eight Bangladeshi males (now residing in Japan) and 14 Japanese males (residing in Japan) participated in this study. All are sedentary, regular university students. The Bangladeshi subject’s duration of stay in Japan was 2.50 ± 2.52 years. The subject’s left hand middle finger was immersed in 5 °C water for 20 min to assess their CIVD response (the experiment was conducted in an artificial climate chamber controlled at 25 °C with 50 % RH). Results Compared with the Bangladeshi (BD) group, the Japanese (JP) group displayed some differences. There were significant differences between the BD and JP groups in temperature before immersion (TBI), which were 33.04 ± 1.98 and 34.62 ± 0.94 °C, and time of temperature rise (TTR), which were 5.35 ± 0.82 and 3.72 ± 0.68 min, respectively. There was also a significant difference in the time of sensation rise (TSR) of 8.69 ± 6.49 and 3.26 ± 0.97 min between the BD and JP groups, respectively (P < 0.05). Moreover, the JP group showed a quick TTR after finishing immersion. Conclusions The Japanese group (temperate) has a higher tolerance to local cold exposure than the Bangladeshi group (tropical) evaluated by the CIVD test.
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Affiliation(s)
- Aklima Khatun
- Graduate school of Fisheries and Environmental Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki, 852-8521, Japan
| | - Sakura Ashikaga
- Graduate school of Fisheries and Environmental Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki, 852-8521, Japan
| | - Hisaho Nagano
- Graduate school of Fisheries and Environmental Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki, 852-8521, Japan
| | - Md Abdul Hasib
- Graduate School of Engineering, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki, 852-8521, Japan
| | - Akihiro Taimura
- Graduate school of Fisheries and Environmental Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki, 852-8521, Japan.
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Kurazumi Y, Ishii J, Fukagawa K, Kondo E, Aruninta A. Ethnic Differences in Thermal Responses between Thai and Japanese Females in Tropical Urban Climate. ACTA ACUST UNITED AC 2016. [DOI: 10.4236/ajcc.2016.51007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Wakabayashi H, Wijayanto T, Lee JY, Hashiguchi N, Saat M, Tochihara Y. A comparison of hydration effect on body fluid and temperature regulation between Malaysian and Japanese males exercising at mild dehydration in humid heat. J Physiol Anthropol 2014; 33:5. [PMID: 24490869 PMCID: PMC3929238 DOI: 10.1186/1880-6805-33-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 01/21/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND This study investigated the effect of hydration differences on body fluid and temperature regulation between tropical and temperate indigenes exercising in the heat. METHODS Ten Japanese and ten Malaysian males with matched physical characteristics (height, body weight, and peak oxygen consumption) participated in this study. Participants performed exercise for 60 min at 55% peak oxygen uptake followed by a 30-min recovery at 32°C and 70% relative air humidity with hydration (4 times each, 3 mL per kg body weight, 37°C) or without hydration. Rectal temperature, skin temperature, heart rate, skin blood flow, and blood pressure were measured continuously. The percentage of body weight loss and total sweat loss were calculated from body weight measurements. The percentage change in plasma volume was estimated from hemoglobin concentration and hematocrit. RESULTS Malaysian participants had a significantly lower rectal temperature, a smaller reduction in plasma volume, and a lower heart rate in the hydrated condition than in the non-hydrated condition at the end of exercise (P <0.05), whereas Japanese participants showed no difference between the two hydration conditions. Hydration induced a greater total sweat loss in both groups (P <0.05), and the percentage of body weight loss in hydrated Malaysians was significantly less than in hydrated Japanese (P <0.05). A significant interaction between groups and hydration conditions was observed for the percentage of mean cutaneous vascular conductance during exercise relative to baseline (P <0.05). CONCLUSIONS The smaller reduction in plasma volume and percentage body weight loss in hydrated Malaysians indicated an advantage in body fluid regulation. This may enable Malaysians to reserve more blood for circulation and heat dissipation and thereby maintain lower rectal temperatures in a hydrated condition.
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Affiliation(s)
- Hitoshi Wakabayashi
- Department of Human Science, Kyushu University, Fukuoka, Japan
- Faculty of Engineering, Chiba Institute of Technology, 2-1-1, Shibazono, Narashino, Chiba 275-0023, Japan
| | - Titis Wijayanto
- Department of Human Science, Kyushu University, Fukuoka, Japan
| | - Joo-Young Lee
- Department of Human Science, Kyushu University, Fukuoka, Japan
- Department of Clothing and Textiles, Seoul National University, Seoul, Korea
| | - Nobuko Hashiguchi
- Department of Health Science, Faculty of Medicine, Kyushu University, Fukuoka, Japan
| | - Mohamed Saat
- School of Health Sciences, Universiti Sains Malaysia, Kelantan, Malaysia
| | - Yutaka Tochihara
- Department of Human Science, Kyushu University, Fukuoka, Japan
- The Open University of Japan, Fukuoka, Japan
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Wijayanto T, Toramoto S, Tochihara Y. Passive heat exposure induced by hot water leg immersion increased oxyhemoglobin in pre-frontal cortex to preserve oxygenation and did not contribute to impaired cognitive functioning. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2013; 57:557-67. [PMID: 22898999 DOI: 10.1007/s00484-012-0583-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 05/06/2012] [Accepted: 07/23/2012] [Indexed: 05/08/2023]
Abstract
This study investigated the effects of passive heat exposure on pre-frontal cortex oxygenation and cognitive functioning, specifically to examine whether the change in pre-frontal cortex oxygenation coincided with cognitive functioning during heat exposure. Eleven male students who participated in this study immersed their lower legs to the knees in three different water temperatures, 38 °C, 40 °C, and 42 °C water in an air temperature of 28 º C and 50 % relative humidity for 60 min. After 45 min of leg immersion they performed cognitive functioning tasks assessing their short-term memory while immersing their lower legs. There were higher rectal temperature (P < 0.05) and higher increase of oxyhemoglobin in both left (P < 0.05) and right (P < 0.05) pre-frontal cortex at the final stage of 45-min leg immersion in the 42 °C condition with unaltered tissue oxygenation index among the three conditions (P > 0.05). No statistical difference in cognitive functioning among the three conditions was observed with a higher increase of oxyhemoglobin during the cognitive functioning in the 42 °C condition for the left (P = 0.05) and right (P < 0.05) pre-frontal cortex. The findings of this study suggest, first, passive heat exposure increases oxygen delivery in the pre-frontal cortex to maintain pre-frontal cortex oxygenation; second, there is no evidence of passive heat exposure in cognitive functioning in this study; and third, the greater increases of oxyhemoglobin in the pre-frontal cortex during cognitive functioning at the hottest condition suggests a recruitment of available neural resources or greater effort to maintain the same performance at the same level as when they felt thermally comfortable.
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Affiliation(s)
- Titis Wijayanto
- Environmental Ergonomics Laboratory, Department of Human Science, Kyushu University, 4-9-1, Shiobaru, Minami-ku, Fukuoka, 815-8540, Japan.
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Tochihara Y, Lee JY, Wakabayashi H, Wijayanto T, Bakri I, Parsons K. The use of language to express thermal sensation suggests heat acclimatization by Indonesian people. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2012; 56:1055-1064. [PMID: 22290685 DOI: 10.1007/s00484-011-0519-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 10/23/2011] [Accepted: 12/23/2011] [Indexed: 05/31/2023]
Abstract
The purpose of this study was to explore whether there is evidence of heat acclimatization in the words used to express thermal sensation. A total of 458 urban Japanese and 601 Indonesians participated in a questionnaire. In addition, in a preliminary survey, 39 native English speakers in the UK participated. Our results showed that (1) for Indonesians, the closest thermal descriptor of a feeling of thermal comfort was 'cool' (75%) followed by 'slightly cool' (7%), 'slightly cold' (5%) and 'cold' (5%), while Japanese responses were distributed uniformly among descriptors 'cool', 'slightly cool', 'neither', 'slightly warm', and 'warm'; (2) the closest thermal descriptors of a feeling of discomfort for Indonesians were less affected by individual thermal susceptibility (vulnerability) than those for Japanese; (3) in the cases where 'cool' and 'slightly cold' were imagined in the mind, the descriptors were cognized as a thermal comfortable feeling by 97% and 57% of Indonesians, respectively; (4) the most frequently voted choice endorsing hot weather was 'higher than 32°C' for Indonesians and 'higher than 29°C' for Japanese respondents; for cold weather, 'lower than 15°C' for Japanese and 'lower than 20°C' for Indonesians. In summary, the descriptor 'cool' in Indonesians connotes a thermally comfortable feeling, but the inter-zone between hot and cold weather that was judged in the mind showed a upward shift when compared to that of Japanese. It is suggested that linguistic heat acclimatization exists on a cognitive level for Indonesians and is preserved in the words of thermal descriptors.
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Affiliation(s)
- Yutaka Tochihara
- Environmental Ergonomics Laboratory, Department of Human Science, Kyushu University, 4-9-1, Shiobaru Minami-ku, Fukuoka, Japan
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Wijayanto T, Toramoto S, Wakabayashi H, Tochihara Y. Effects of duration of stay in temperate area on thermoregulatory responses to passive heat exposure in tropical south-east Asian males residing in Japan. J Physiol Anthropol 2012; 31:25. [PMID: 22974339 PMCID: PMC3514345 DOI: 10.1186/1880-6805-31-25] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 08/20/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In this study, we investigated the effects of duration of stay in a temperate area on the thermoregulatory responses to passive heat exposure of residents from tropical areas, particularly to clarify whether they would lose their heat tolerance during passive heat exposure through residence in a temperate country, Japan. METHODS We enrolled 12 males (mean ± SE age 25.7 ± 1.3 years) from south-east Asian countries who had resided in Japan for a mean of 24.5 ± 5.04 months, and 12 Japanese males (age 24.1 ± 0.9 years). Passive heat exposure was induced through leg immersion in hot water (42°C) for 60 minutes under conditions of 28°C air temperature and 50% relative humidity. RESULTS Compared with the Japanese group, the tropical group displayed a higher pre-exposure rectal temperature (P < 0.01) and a smaller increase in rectal temperature during 60 minutes of leg immersion (P = 0.03). Additionally, the tropical group showed a tendency towards a lower total sweat rate (P = 0.06) and lower local sweat rate on the forehead (P = 0.07). The tropical group also had a significantly longer sweating onset time on the upper back (P = 0.04) compared with the Japanese groups. The tropical group who stayed in Japan for > 23 months sweated earlier on the forehead and upper back than those who stayed in Japan < 11 months (P < 0.01 and P = 0.03 for the forehead and upper back, respectively). There was a positive correlation between duration of stay in Japan and total sweat rate (r = 0.58, P <0.05), and negative correlations between duration of stay and sweating onset time on the forehead (r = -0.73, P = 0.01) and on the upper back (r = -0.66, P = 0.02). Other physiological indices measured in this study did not show any difference between the subjects in the tropical group who had lived in Japan for a shorter time and those who had lived there for a longer time. CONCLUSIONS We conclude that the nature of heat acclimatization of the sweating responses to passive heat exposure that are acquired from long-term heat acclimatization is decayed by a stay in a temperate area, as shown by the subjects in our tropical group. We did not find any evidence of a decay in the other physiological indices, indicating that heat tolerance acquired from long-term heat acclimatization is not completely diminished through residence in a temperate area for less than 4 years, although some aspects of this heat tolerance may be decayed.
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Affiliation(s)
- Titis Wijayanto
- Department of Human Science, Faculty of Design, Kyushu University, 4-9-1, Shiobaru, Minami-ku, Fukuoka, 815-8540, Japan.
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Ethnic differences in thermoregulatory responses during resting, passive and active heating: application of Werner’s adaptation model. Eur J Appl Physiol 2011; 111:2895-905. [DOI: 10.1007/s00421-011-1912-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2010] [Accepted: 03/07/2011] [Indexed: 10/18/2022]
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