Long-term changes in hazardous heat and cold stress in humans: multi-city study in Poland

Magdalena Kuchcik,Agnieszka Halaś,Krzysztof Błażejczyk

doi:10.1007/s00484-020-02069-7

Abstract

Significant changes in climate variables in the last decades resulted in changes of perceived climate conditions. However, there are only few studies discussing long-lasting changes in bioclimatic conditions. Thus, the purpose of this paper is to present the temporal and spatial distribution of hazardous heat and cold stress conditions in different regions of Poland. Its focus is on long-lasting changes in such conditions in the period 1951–2018. To assess changes in hazardous thermal stress conditions, the Universal Thermal Climate Index (UTCI) was used. UTCI values at 12 UTC hour (respectively 1 pm winter time, 2 pm summer time) were calculated daily based on air temperature, relative humidity, total cloud cover and wind speed at 24 stations representing the whole area of Poland. We found that the greatest changes were observed in minimum (1.33 °C/10 years) and average (0.52 °C/10 years) UTCI values as well as in cold stress frequency (− 4.00 days per 10 years). The changes vary seasonally and regionally. The greatest increase in UTCImin and decrease in cold stress days were noted from November to March and had the highest values in north-east and east Poland, and also in the foothills of the Carpathian Mountains. The trends in maximum UTCI are much smaller and not always positive. The spatially averaged trend in UTCImax for Poland as a whole was 0.35 °C/10 years and the increase in heat stress days was 0.80 days/10 years. The highest increases in UTCImax and heat stress days were noted in eastern and south-eastern Poland.

Highlights

Human beings are permanently under the influence of atmospheric stimuli which impact individual systems and organs in the body
Universal Thermal Climate Index (UTCI) reflects the intensity of heat and cold stress in humans, which are physiological reactions of an organism to atmospheric stimuli
We examined minimum (UTCImin), mean (UTCIavg) and maximum (UTCImax) values and frequencies of selected thermal stress categories

Summary

Introduction

Human beings are permanently under the influence of atmospheric stimuli which impact individual systems and organs in the body. Special attention is usually paid to the so-called “thermal environment”, which comprises both atmospheric heat exchange conditions (stress) and physiological response (strain) (Jendritzky et al 2012). Human organisms react to ambient stimuli and endeavour to balance the heat exchange and to preserve thermal equilibrium of the body core. Balancing the human heat budget in variable atmospheric conditions is achieved by the autonomous thermoregulatory system, supported by behavioural adaptation (Havenith 2001; Glossary 2003; Kenney and Munce 2003; Parsons 2003). Heat equilibrium of the body is mainly regulated through increased bodily sweating and consequent evaporation-induced cooling (Elizondo and Bullard 1971; Givoni and Goldman 1973; Kenney 1985; Hajat et al 2007; Cheshire 2016).

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