Abstract
In recent years, the risk of heat disorder in daily life has increased dramatically because the thermal environment has been deteriorating. The main objective of this study was to examine regional differences in the relationship between heat disorder incidence rate and heat stress indices at Yamanashi Prefecture, Japan. Daily maximum air temperature and daily maximum WBGT were used as heat stress indices in each region. Nonlinear regression analysis was used to examine the regional difference in the relationship between the heat disorder incidence rate and heat stress indices in each region. The heat disorder incidence rate was correlated with both indices of heat stress in all regions. However, the more appropriate heat stress index for heat disorder prevention differed among regions. The distributions of heat stress indices, such as the slope of regression curve and the temperature threshold, differed in each region, irrespective of the index used. Therefore, the criteria for thermal conditions for heat disorder prevention need to be determined for each region, considering the regional characteristics of the relationship between the heat disorder incidence rate and heat stress indices.
Highlights
In recent years, the thermal environment has been deteriorating because of global warming and the heat island phenomenon [1]
The results of this study show that the heat disorder incidence rate was correlated with each heat stress index in all regions, but the more appropriate heat stress index for heat disorder prevention differed among regions
This study indicates that it may be difficult to remove regional differences in heat disorder incidence rate to prevent heat disorder in Yamanashi Prefecture, even if daily maximum wet-bulb globe temperature (WBGT) is used as the heat stress index
Summary
The thermal environment has been deteriorating because of global warming and the heat island phenomenon [1]. Both the Japan Sports Association (JSA) and Japanese Society of Biometeorology (JSB) announced guidelines for the prevention of heat disorder in 1993 and in 2007, respectively, and both organizations used WBGT as the heat stress index to set the criteria for thermal conditions [6] This is because air temperature and humidity and radiant heat are important factors determining the heat disorder incidence rate [14]; WBGT, which includes all three factors, is considered to be most informative index for the thermal conditions that indicates heat disorder probability [10] and is most widely used as the index of heat stress in the world [15]. Previous research has identified a stronger positive correlation between the heat disorder incidence rate and WBGT than the correlation with daily maximum air temperature and has suggested that the use of WBGT removes regional differences in the relationship between the heat stress index and the heat disorder incidence rate [11]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
