Effect of Real-fire Training on Vascular Function

Overview

Fire-fighters are at increased risk of death from heart attacks when compared to other emergency service professionals whose jobs involve similar components such as emergency call-outs and shift work. The unique risk to fire-fighters is likely to reflect a combination of factors including extreme physical exertion, mental stress, heat and pollutant exposure. In the largest analysis of cause of death amongst on-duty fire-fighters, fire-fighter deaths were classified according to the duty performed during the onset of symptoms or immediately prior to any sudden death. The majority of deaths due to a cardiovascular cause (i.e. heart attack) occurred during fire-suppression whilst this activity represented a relatively small amount of a fire-fighters professional time. Fire simulation training centers offer a unique opportunity to assess the heart, blood and blood vessel response to fire suppression in a controlled environment. In this study the investigators will assess healthy career fire-fighters on two occasions: following a fire-suppression training exercise in a purpose built real-fire training center, and following a sedentary period as a control. The investigators will take blood samples to measure platelet activity (platelets are the particles in blood that help blood clot) and will examine how blood clots outside of the body. The investigators will then perform studies placing small needles in the arm to assess blood vessel function following fire suppression. By undertaking this comprehensive assessment of blood, blood vessel and heart function we hope to understand the mechanisms whereby the risk of a heart attack is influenced by fire suppression. The investigators hypothesize that following the fire-suppression exercise firefighters blood will clot more readily and their blood vessels will not relax properly which are two of the main processes in the development of a heart attack.