A new study by Bond University, in conjunction with the Queensland Fire and Emergency Service, has found firefighters lost an average of 1.2 kilograms in just 30 minutes of being exposed to the heavy demands and heat of structural firefighting.
The report reveals the rapid weight loss equates to an average fluid loss of 1.2 litres, as a result of heavy sweating from rapid increases in body temperature and high levels of physical activity.
The pilot study by Bond University's world-first Tactical Research Unit (TRU), which is dedicated to improving the health and performance of front-line tactical employees, was completed with Queensland Fire and Emergency Service members, including regional wellness manager Inspector Richard Gorey, and Bond University Doctor of Physiotherapy student Adam Walker.
It considered the impact of both heat and workload on the hydration levels of firefighters, studying firefighters aged between 29 and 48 with one to 16 years experience.
Associate Professor Rob Orr, who co-leads the TRU with Dr Rod Pope, said the study aimed to better understand the physiological impact of fighting fires, so improved strategies to keep firefighters hydrated and healthy could be developed.
"What we have found is that firefighters lose sweat at a rate potentially higher than a person undertaking high intensity exercise," said Dr Orr.
"The high level of fluid loss continues even after they leave the fire environment, if they are still in their turn out gear.
"Body temperature increased significantly - and quite quickly - so it is really important for firefighters to remove their flash hood as soon as they are able to, after exiting the fire, to allow their body to cool and speed up their recovery in preparation for possible re-entry.
"We also found some firefighters actually arrived already slightly dehydrated, so making sure those on the job keep their hydration levels up is another important factor."
Dr Orr said the study looked at changes in body weight at regular intervals within the first hour of being exposed to fire.
"The results showed firefighters lost an average of 0.73 kilograms immediately after exposure to fire and another 0.47 kilograms after 15 minutes of being outside the fire," he said.
"Per hour, the high temperatures and high level of physical activity led to an average loss of one to three kilograms.
"However, the rate of fluid loss was likely even higher, due to sweat loss into the clothing worn, which was not accounted for."
Dr Orr said ear temperature was also measured, showing an average spike of 2.4 degrees in body temperature immediately after exposure to fire.
"After another 15 minutes of being outside the fire, the temperature dropped by 1.2 degrees on average, but was still elevated by an average of 1.2 degrees 30 minutes post-fire," he said.
"This means even outside the fire, it took firefighters wearing the flash hood a significant amount of time to cool back down to their normal temperature."
Inspector Gorey said the study provided important data on the effect of fighting fires on the muscular, skeletal, physiological and cognitive system, to ensure the best treatment options and injury prevention strategies were implemented.
”Through this research we are hoping to find new and improved data to base rehabilitation policies on, for firefighters involved in both structural or wild land fire events," said Inspector Gorey.
"If we can better understand the effects on the body, we can tailor treatment approaches, injury prevention strategies and return to work reconditioning strategies to improve the health and wellbeing of firefighters over the long term."
Bond University's TRU is a network of multi-disciplinary, international experts investigating tactical personnel across firefighting, military, law enforcement and first responder organisations.
The overarching aim of the TRU is to optimise the physical and cognitive capabilities and safety of these personnel, leading to improvements in their wellbeing and occupational performance and ensuring new research findings are shared across the different tactical populations.
Dr Orr said the work was vital, with tactical responders often susceptible to a wide range of specific health and injury issues.
"Essentially our aim is to improve both the health and performance of tactical personnel in the line of duty, so we are looking after those who look after us," he said.
For more information on the TRU, click here.