Firefighters exposed to extreme heat risk heart attack

Firefighters exposed to extreme heat are at increased risk of blood clotting and heart attack, research has suggested. 

The study researchers at the University of Edinburgh and published in the journal Circulation, could explain why cardiovascular events – such as heart attacks – are the leading cause of death among on-duty firefighters, according to the British Heart Foundation, which funded the research.

The study has recommended that fire services help to reduce the number of firefighters suffering heart attacks by limiting the time individuals spend tackling a blaze, as well as helping them to cool down and rehydrate after exposure.

The study randomly selected 19 non-smoking, healthy firefighters from the Scottish Fire and Rescue Service to participate in two exercises at least a week apart, including a fire simulation and a control exposure.

The simulation exposed 17 participants to extremely high temperatures, resulting in an average increase in core body temperature of 1 degree Celsius among participants as they attempted a mock rescue from a two-storey structure.

The researchers then measured blood vessel function and blood clotting and discovered that firefighters’ blood vessels failed to relax in response to medication. Their blood also became stickier and was more than 66% more likely to form potentially harmful clots after the fire simulation.

The research team believe this increase in clotting was caused by a combination of fluid losses in sweat and an inflammatory response to the fire simulation, which resulted in the blood becoming more concentrated and thus more likely to clot.

The study also indicated that exposure to fire simulation causes minor injury to the heart muscle in healthy firefighters.

The BHF added: “The study’s findings are not directly applicable to the public; however, the combination of heavy physical exertion, high ambient temperatures and air pollution can present an increased risk in everyday life. As such, the researchers recommend that anyone who is exercising in high ambient temperatures should take regular breaks, keep well hydrated and allow time to cool down afterwards.”