Firefighters may be at greater risk of heart attack and stroke, research suggests.
A study has found that heat exposure and physical exertion during firefighting can increase blood clotting and impair blood vessel function.
The findings may explain why heart attacks are the leading cause of death amongst on-duty firefighters, researchers say.
Experts are calling on fire services to help to reduce the number of heart attacks by limiting the time firefighters spend tackling a blaze.
They say helping fire crews to cool down and rehydrate after exposure to high temperatures could improve their heart health.
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.
Researchers at the University’s Centre for Cardiovascular Science randomly selected 19 non-smoking, healthy firefighters to take part in the study.
All participants completed 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 1 degree Celsius on average
The study found their body temperatures remained high for three to four hours following the fire simulation.
Firefighters wore heart monitors to check for signs of strain that might indicate a lack of oxygen being delivered to the heart muscle.
Blood samples were taken before and after the exercise, including measurement of a protein called troponin that is released from the heart when it is damaged.
Researchers found that firefighters’ blood became stickier and was more likely to form potentially harmful clots after the fire simulation.
They also discovered that firefighters’ blood vessels failed to relax in response to medication.
The researchers also showed that exposure to fire simulation causes minor injury to the heart muscle in healthy firefighters.
The study, funded by the British Heart Foundation, is published in the journal Circulation.
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.