Firefighter heart risk a result of heat exposure, study suggests

A study conducted by the University of Edinburgh’s Centre for Cardiovascular Science has found that heat exposure and physical exertion during firefighting can increase blood clotting and impair blood vessel function.

The researchers speculated that the findings may explain why heart attacks are the leading cause of death amongst on-duty firefighters.

The study, funded by the British Heart Foundation and published in the journal Circulation and involved randomly selecting 19 non-smoking, healthy firefighters to complete two exercises at least a week apart. The first involved a fire simulation activity as they attempted a mock rescue from a two storey structure.

The second involved 20 minutes of light duties similar to those performed during a shift without an emergency call out. During the fire simulation, participants were exposed to extremely high temperatures that raised their core body temperature by around one degree Celsius on average.

However, findings indicated that their body temperatures remained high for three to four hours following the fire simulation. The firefighters wore heart monitors to check for signs of strain that might indicate a lack of oxygen being delivered to the heart muscle and found their blood became stickier and was more likely to form potentially harmful clots after the fire simulation.

They research also identified that firefighters’ blood vessels failed to relax in response to medication.

The scientists are calling on fire services to help to reduce the number of heart attacks by limiting the time firefighters spend tackling a blaze. The researchers suggested that fire crews should cool down and rehydrate after exposure to high temperatures could improve their heart health.

Professor Nick MillsBHF senior clinical research fellow, Centre for Cardiovascular Science explained: “Our study has shown 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. However, we’ve also found that there are simple measures, such as staying well hydrated, that firefighters can take to reduce this risk.”

Dr Mike Knapton associate medical director, British Heart Foundation, said: “Firefighters routinely risk their lives to save members of the public. The least we can do is make sure we are protecting their hearts during the course of their duties.”