By Alicia Chang
The Associated Press

CAMBRIDGE, Mass. — Firefighters face a far greater risk of dying of heart problems while battling a blaze than was thought, suggests a large U.S. study that offers more evidence of their need to stay in shape. The risk of a heart-related death while putting out a fire was up to 100 times higher than the risk during down time, Harvard researchers found, even though fighting fires accounts for only a small percentage of these workers' time.

About 100 firefighters die in the line of duty each year and previous research has shown that nearly half of the deaths are due to heart disease. The vast majority - about 70 percent - of the nation's roughly 1 million firefighters are volunteers.

Experts say diet and exercise should be priorities at the firehouse.

"You may not be able to prevent all these deaths, but to the degree you can prevent some deaths by paying attention to underlying risk factors and better fitness programs, that's the goal," said Dr. Linda Rosenstock, dean of the UCLA School of Public Health, who was not involved in the study.

The study, published in Thursday's New England Journal of Medicine, doesn't address whether firefighters have an overall higher risk of dying from heart disease than the general population.

Rosenstock said fire departments could do more to improve health by requiring annual physicals and fitness tests. Departments also should have wellness and fitness programs to reduce heart disease risk factors such as obesity and high blood pressure, she said.

Firefighting is a physically demanding job that involves heavy lifting of equipment and exposure to toxic chemicals. Recruits are generally healthy and physically fit, but their health can decline over time because many firehouses don't require regular exercise or yearly medical exams. Also, the health requirements are usually less stringent for volunteers, who tend to continue firefighting as they age, a time when most heart problems occur.

In the Harvard study, researchers examined a federal registry of 1,144 on-duty firefighter deaths between 1994 and 2004. Excluded were the 343 firefighters who perished in the Sept. 11, 2001 terrorist attacks.

Nearly 40 percent - or 449 - of the on-duty deaths during that period were due to heart disease. Thirty-two percent of the heart-related deaths occurred while fighting blazes; 13 percent responding to an alarm; 17 percent returning from a call and 13 percent during physical training.

The researchers also calculated the odds of dying from a heart attack by taking into account the estimated amount of time spent performing different duties.

They found the risk of death from heart disease was highest during active firefighting - up to 100 times greater than the risk of dying during administrative work - though firefighting made up no more than 5 percent of a firefighters' time. Increased risk of death was also found for other emergency duties such as responding to a call and returning from the scene of a fire.

Researchers believe mental stress and overexertion combined with factors such as being overweight and in poor shape may increase the risk of dying from heart disease.

"There's direct evidence to support that certain specific activities that firefighters do could trigger coronary heart disease events," said lead author Dr. Stefanos Kales of the Harvard School of Public Health.

The study was funded by the National Institute for Occupational Safety and Health and the Massachusetts Public Employees Retirement Administration Commission. Kales and another author have served as paid expert witnesses in workers' compensation cases, including some involving firefighters.

Fire Sgt. Jeff Brause of Michigan had a heart attack in 2004 while responding to a house fire. Brause, who was 45 at the time, didn't have a family history of heart disease.

"I started getting a burning sensation in my chest," he recalled. "I thought I must be getting old or maybe pulled a muscle."

The pain worsened during the ride to the scene and Brause sought an ambulance. On the way to the hospital, paramedics had to deliver a defibrillation shock to restart his heart. Doctors later told Brause he had a blockage in his heart.

Before his heart attack, Brause said he often ate greasy fast food and didn't exercise regularly. "I didn't eat the world's greatest," he admitted.

Since then, Brause has given up junk food and hits the treadmill and lifts weights three times a week.

Firefighter groups are increasingly taking notice of heart risk. The National Volunteer Fire Council in 2003 began an awareness program promoting fitness and nutrition, and volunteers offer free health screening and demonstrate healthy cooking and fitness techniques.