Firefighters at Higher Risk of Heart Attack Due to Heat, Exertion

Exposure to heat and the physical exertion required to control a fire is putting firefighters at risk of heart attack, a new research suggests.

The study funded by the British Heart Foundation (BHF) found that tackling fires puts a strain on the heart, increases blood clotting and worsens the function of blood vessels. Previous work has shown that firefighters have the highest risk of heart attack of all the emergency services.

A heart attack is the leading cause of death for on-duty firefighters across the world and they tend to suffer cardiac arrests at a younger age than the general population, reports the UK-based news agency BT.com.

In the US, around 45% of on-duty deaths each year among firefighters are due heart issues, with most heart attacks occurring as fires are put out.

In the new study, published in the journal Circulation, 19 non-smoking healthy firefighters – 16 of whom were men – took part in a standard training exercise.

They attended on two occasions, at least one week apart, and either performed a mock rescue from a two-storey building for 20 minutes or undertook light duties, in the case of the control group, for 20 minutes.

Those taking part in the rescue had core body temperatures that rose by 1C and stayed that way for three or four hours. There was also some weight loss among this group, while their blood vessels also failed to relax in response to medication. Their blood became “stickier” and was more than 66% more likely to form potentially harmful clots than the blood of people in the control group.

The researchers, from the University of Edinburgh, said the results showed “striking changes in physiological measures of cardiovascular function”.

Participation in fire simulation training places an inordinate strain on the cardiovascular system, they said, adding that they believed the increase in clotting was caused by a combination of fluid loss in sweat and an inflammatory response to the fire simulation, which resulted in the blood becoming more concentrated and therefore more likely to clot.

They also found that exposure to fire causes minor injury to the heart muscle.

“Nearly half of all firefighters who die on duty are killed by heart disease,” said Professor Nick Mills, from the University of Edinburgh, who led the research.

“There is a direct link between the heat and physical activity levels encountered by firefighters during the course of their duties and their risk of suffering a heart attack.”

The findings have prompted the researchers to call on fire rescue services to limit the time each firefighter spends tackling a blaze, as well as helping them to cool down and rehydrate with plenty of fluids afterwards.