As if firefighters did not have enough to deal with, a new study has found that firefighters who died of cardiovascular problems while on the job were most often doing intense physical activity right before the attack.

Researchers based their findings on data gathered from the National Institute for Occupational Safety and Health which covered the deaths that occurred while firefighters were on duty during the years 1998 to 2012. The data included ratings on the intensity of the firefighters' activities prior to the cardiovascular attack.

The study has found that between the years 1998 and 2012, there had been 199 fatal cardiovascular events while firefighters were on duty. Of the 199, 167 were heart attacks, 12 were from irregular heartbeat, 3 were from stroke. The rest of the deaths were caused by other cardiovascular problems. Vigorous activity lasting for an average of 33 minutes has been tracked for 148 of the cardiovascular attacks.

Of this 148, 94 had high cholesterol, 93 had high blood pressure, 42 were smokers, 22 had diabetes and 46 had family members with heart disease.

There were 51 firefighters who were reported to be engaged in light to moderate physical activity at the time of the event, which led to the cardiovascular attack while they were on the job. Of this group, 38 had high blood pressure, 34 had high cholesterol, 20 were smokers, 7 had diabetes and 11 had family members with heart disease.

Of the 199 firefighters who died, CPR was performed in 178 of them, while an external defibrillator was used for 151. Eighty-eight of them were actively engaged in firefighting at the moment the cardiovascular attack happened, and 61 were in the process of responding to an emergency. The firefighters who died had an average age of 49 years, and had served as firefighters for an average of 22 years.

About 35 percent of the events occurred at the fire station, and they were triggered by either fitness training or the lifting of heavy fire firefighting equipment.

"Knowing that these fatal heart attacks and other vascular events occur relatively frequently, fire departments and other workplaces need to be prepared to recognize these events and screen for those who may be at higher risk," said study author Amna Zarar, MD, a researcher at Zeenat Qureshi Stroke Institute in St. Cloud, Minn. "People also need more awareness of the symptoms and signs that can precede or occur with a heart attack or stroke, along with better screening for risk factors with regular health check-ups."

The researchers have recommended that tests for high cholesterol, blood sugar tests for diabetes and stress EKG tests be done for those at high risk of having a cardiovascular attack.

The findings of the study will be presented at the American Academy of Neurology's 66th Annual Meeting in Philadelphia, to be held from April 26 to May 3.