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Volume 41 (2004)
- Issue 4 Pages 131-
- Issue 3 Pages 77-
- Issue 1 Pages 5-
Volume 41, Issue 1
Displaying 1-9 of 9 articles from this issue
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Original Articles
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Kazuo Nagano, Tetsumi Horikoshi2004 Volume 41 Issue 1 Pages 5-18
Published: 2004
Released on J-STAGE: November 12, 2004
JOURNAL FREE ACCESSThe purpose of this study is to quantitatively determine the combined effect of lower temperature and noise on the human psychological responses and to propose a new environmental index for expression of the combined effect of them. In this study, twenty-two male students were exposed to the combined twenty conditions of operative temperatures (19, 22, 25, 28°C) and noise levels (46.6 dB (A): air-conditioning noise; 58.5, 72.9, 79.9, 95.5 dB (A): traffic noise). The subjects reported their sensation votes for each combined condition using the linear unipolar scales. As a result, thermal condition affects noisy sensation and auditory condition affects hot sensation significantly in addition to the effect of thermal/auditory condition on hot/noisy sensation. Consequently, both of temperature and noise affect the universal comfort and discomfort sensation. Equi-comfort and equi-discomfort charts constituted with the thermal and auditory comfort/discomfort sensation votes, and with the operative temperature and noise level were proposed to quantitatively evaluate the combined effect of thermal and auditory environment. They are valid as new comfort indices within this experimental conditions.
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—Numerical analysis and subject experiment—Ikue Mori, Shuichi Hokoi, Satoru Takada2004 Volume 41 Issue 1 Pages 19-30
Published: 2004
Released on J-STAGE: November 12, 2004
JOURNAL FREE ACCESSIn this study, numerical analysis by using a thermoregulation model of the human body and subject experiment were carried out in order to examine the physiological response to partial cooling of the human body in a warm environment. Differences in physiological response were analyzed by comparing cooling of the head, trunk and extremities. In each case, heat loss was loaded for equal areas of skin. When the head was cooled, total heat loss from the whole body was less and mean skin temperature and mean body temperature were higher, than when the trunk or extremities were cooled. This was because of the decrease in thermal evaporation mainly caused by a decrease in head core temperature. From this analysis, it was assumed that greater heat loss is expected when cooling body parts other than the head, if the degree of cooling is equal. This hypothesis was supported by physiological responses observed in an experimental subject, whose feet or head were cooled by blowing cold air.
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Review
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Akio Hoshi, Yutaka Inaba2004 Volume 41 Issue 1 Pages 31-38
Published: 2004
Released on J-STAGE: November 12, 2004
JOURNAL FREE ACCESSRecently in Japan, deaths of heat disorders have been increasing due to elevation of temperature in summer caused by global warming. Heat disorders are considered to be preventable if appropriate measures are taken. Therefore, the recommendation such as prediction model using WBGT and heat index is utilized in order to prevent the heat disorders. In Japan, however, there is no model that evaluates a risk of the occurrence of heat disorders, expect for the sports activity. We tried to prepare the prediction models of heat disorders in Japan.
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Symposium on "Forecast and prevention of heatstroke and global warming"
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Kozo Hirata, Taketoshi Morimoto2004 Volume 41 Issue 1 Pages 39
Published: 2004
Released on J-STAGE: November 12, 2004
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Toshiyuki Minami2004 Volume 41 Issue 1 Pages 41-44
Published: 2004
Released on J-STAGE: November 12, 2004
JOURNAL FREE ACCESSGlobal warming and the so-called heat island phenomenon have rapidly brought about rising temperatures since the 1980s, causing increased numbers of heat related disorder in summer. The Japan Weather Association has outlined preventive steps for heat related disorders and has provided them to the media from summer 2002. This review summarizes changes in temperature and in the ecosystem caused by global warming and introduces the format and analysis methods used in order to understand the preventive steps.
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Mitsuru Ando, Shoji Yamamoto, Shinji Asanuma2004 Volume 41 Issue 1 Pages 45-49
Published: 2004
Released on J-STAGE: November 12, 2004
JOURNAL FREE ACCESSThe Intergovernmental Panel for Climate Change (IPCC) in its third assessment report (TAR) on climate change has forecast that global warming will have a major impact on health conditions. TAR predicts the morbidity and mortality rate in society and vector-borne diseases caused by climate change. The rise in temperature due to global warming will directly affect human health in the form of heat stress and also indirectly through various vectors and pathogens. The study of heatstroke and excessive death due to heat stress among the elderly suggests that summer heat will affect greater numbers of people more frequently because of global warming. It has been reported that during intense summer heat when temperatures rise above a threshold value, heat related diseases increased noticeably. In order to evaluate the effects of global warming on health conditions, it is necessary to gather data on the health of the subjects in question, their susceptibility to disease, and threshold temperatures.
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Seiichi Nakai2004 Volume 41 Issue 1 Pages 51-54
Published: 2004
Released on J-STAGE: November 12, 2004
JOURNAL FREE ACCESSThe number of deaths from heatstroke in Japan was examined according to vital statistics and newspaper reports. Correlations were seen between the number of deaths from heatstroke and the yearly number of days with maximal temperatures of 32°C, 34°C and 36°C. In years when there were days with maximal temperatures over 38°C, the incidence of heatstroke was high. As for heat affected disorder during sports, it was found that 1) it occurred throughout Japan, 2) the incidence was high during intensive running, 3) it occurred not only outdoors but also indoors with a high incidence rate for young males (first years in particular), 4) it occurred at dry-bulb temperatures higher than 24°C, wet-bulb temperatures higher than 20°C, and WBGT higher than 23°C, and 5) the incidence rate was related to clothing worn and the physical condition of the subject. The guidelines of the Japan Amateur Sports Association for the prevention of heat related disorder during sports activities are based on data from incidences of heat related disorder and environmental temperature. These are: level is safe when WBGT is below 21°C, requires care when WBGT is between 21°C–25 °C, requires caution at WBGT of 25°C–28 °C, requires utmost caution at WBGT of 28°C to 31°C, and must discontinue activity when WBGT is above 31°C. In daily life, people are often exposed to artificially controlled environments as well as to rapid changes in temperature caused by moving from one such environment to another. Therefore, to evaluate the relationship between heat related disorder and temperature, it is necessary to consider not only changes in weather conditions but also changes in temperature in artificially created environments.
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Akira Takamata2004 Volume 41 Issue 1 Pages 55-59
Published: 2004
Released on J-STAGE: November 12, 2004
JOURNAL FREE ACCESSThermoregulatory sweating decreases extracellular fluid (ECF) volume and increases ECF osmaolality. In addition, increased skin blood flow during heat stress decreases venous return to the heart, resulting in cardiopulmonary baroreceptor unloading. Plasma hyperosmolality inhibits both thermally-induced cutaneous vasodilaiton and sweating by elevating the body core temperature (Tc) thresholds for these responses. The decreased ECF volume, or cardiopulmonary baroreceptor unloading, during heat stress inhibits thermoregulatory cutaneous vasodilation and also increases heart rate via cardiopulmonary baroreceptor reflexes/. Therefore, fluid ingestion is necessary to maintain thermoregulatory and cardiovascular function during heat stress. It is necessary to replace sodium for full recovery from thermal dehydration. The optimal sodium concentration in beverage might be dependent on the level of heat acclimation, because heat acclimation reduces sweat sodium concentration. Fluid ingestion before exercise is more beneficial to maintain thermoregulatory and cardiovascular function during exercise in a hot environment than fluid ingestion during exercise. Thus, timing of fluid ingestion influences thermoregulation and cardiovascular regulation during exercise.
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Yoshimitsu Inoue2004 Volume 41 Issue 1 Pages 61-66
Published: 2004
Released on J-STAGE: November 12, 2004
JOURNAL FREE ACCESSThis paper has attempted to address the characteristics of heat loss responses in children and the elderly (relative to young adults) based on our data, and to propose a recommendation for preventing their heat illness. Prepubertal children have the characteristics of heat loss responses that greater cutaneous vasodilation on their head and trunk compensates for an underdeveloped sweating function relative to young adults. Therefore, when air temperature is lower than skin temperature, children are able to thermoregulate as efficiently as young adults, as a consequence of the heat loss characteristics and a greater surface area-to-mass ratio. However, when air temperature is higher than skin temperature, their core temperature becomes higher than in young adults due to the underdeveloped sweating function and a higher rate of heat absorption with the greater surface area-to-mass ratio. In the elderly, heat loss effector function decreases with aging. The decrease may first involve cutaneous vasodilation, then sweat output per gland, and finally active sweat gland density; and it may proceed from the lower limbs to the back of the upper body, the front of the upper body, then the upper limbs and finally to the head. Exercise training and heat acclimation improve heat loss responses in children and the elderly, although the degree of improvement seems to be inferior in children and the elderly compared to young adults. Recommendations (with respect to periodic drinking, frequent rest period, proper sports-wear etc.) for preventing heat illness were proposed in consideration of age, based on the physiological responses to heat and exercise reviewed in this paper and the “The Guidebook for the Prevention of Heat Illness during Sports Activity” (Japan Amateur Sports Association, Task Group, 1993).
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