Uncomfortability of bio-thermal conditions during sweltering days at different intensity of physical activity (based on the area of north-western Poland)

The work is a description of onerousness of bio-thermal conditions occurring at midday during days of tmax≥30°C in three towns located in north-western Poland: Kolobrzeg, Chojnice and Poznan, for people undertaking physical activity of varying intensity. Based on the meteorological data for 12 a.m. UTC from the period 1981–2016 average values of biometeorological (HIS, STI) and thermophysiologial (HR, Oh_H, SW, DhRna) indices, as well as their extreme values and amplitudes were calculated. The frequency of conditions burdening human body, when undertaking exercise outdoors, was also determined. The analyses showed that in the midday hours an increased physical activity leads to an increase in intense thermal sensations and a significant burdening of the human body with heat stress. A potential risk of overheating, that could occur within an hour of intense effort, was noted. A serious risk of dehydration of the body, even at moderate activity, was also indicated. Particularly burdening conditions, with high sultriness and a possibility of hyperthermia were observed in Kolobrzeg.