Struktura bilansu cieplnego człowieka w różnych warunkach pogodowych i przy różnej aktywności fizycznej

Human heat balance structure at various weather and at different physical activity

Summary: Weather conditions strongly influence human heat balance outdoors. Some of the existing research refers also to various physical activity outdoors. The aim of the paper is to present preliminary results of the studies dealing with the changes in the human heat balance during prolonged outdoor exposition at various meteorological conditions, both at the night and at the day time. We have also examined human heat balance during various physical activity outdoors. The studies were carried out on the research station of the Jagiellonian University in Gaik-Brzezowa (25 km S from Kraków, longitude 49°52' N, latitude 20°04' E, Hs=302 m above sea level). 20 young volunteers within the age category of 21-25 years and with normal weight to high ratio were examined. Skin temperature of torso, forearm and thigh was measured and registered every 1 min. Mean skin temperature (Tsk) was calculated as follows: Tsk = 0.42 Ttorso + 0.19 Tforearm + 0.39 Tthigh. The observers were exposed outdoors for 4 hours in upright posture (July 2001) and during varying activity (M=60, 70, 120 W m-2 - July 2003). The observers reported their thermal sensations. Simultaneously, meteorological elements, i.e. air temperature (Ta), solar radiation (global - Kglob, direct - Kdir, diffuse - Kdif and reflected - Kref), wind speed (v) and air vapour pressure (vp) were registered by automatic weather station. The human heat balance components were calculated for every person subject with the use of man-environment heat exchange model MENEX_2002 (Błażejczyk 2004a). The results show great influence of actual weather on human heat balance. During outdoors exposure the solar radiation is of special importance. Its lack or presence stimulate physiological response to cold and to warm conditions. The range of adaptation processes seems to be similar to observed in climatic chambers. Acclimation mechanisms of an organism lead to stabilisation of man-environment heat exchange components after about 1-2 hours exposure even at varying meteorological conditions. Physical activity significantly influence skin temperature and evaporative heat loss outdoors. However, adaptation processes lead to relative equilibrium of heat gains and heat losses.

Trepińska J., Olecki Z. (red.), 2006, Klimatyczne aspekty środowiska geograficznego, IGiGP UJ, Kraków, s. 161-172.

Instytut Geografii i Gospodarki Przestrzennej UJ

ISBN 83-88424-16-5

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