TY JOUR TI Comprehensive assessment of the functional state of firefighters under heat stress conditions KW firefighters KW heart rate KW blood saturation KW heat stress KW physical activity KW breathing apparatus KW life safety JO Siberian Fire and Rescue Bulletin AU Bakanov, M.O. AU Grinchenko, B.B. AU Zakharov, D.Y. PY 2026 IS 2026 PB FSBEE HE Siberian Fire and Rescue Academy EMERCOM of Russia