BELOIT (WIFR) -- The stress of hearing alarms that alert firefighters is the same as taking part in an Olympic sport. That's the findings of a local study that’s gaining international attention.

“I would feel my heart jump out of my chest," Deputy Fire Chief Joe Murray said as he explained the feeling of waking up in the middle of the night to an alarm, alerting firefighters of a fire.

“Just imagine someone startles you when you're in a dead sleep and you wake up and sometimes you get a little disoriented,” he explained.

Firefighters in Beloit no longer have that sudden jolt. Instead it's a gradual increase.

"Basically it’s the difference of gently waking someone or gently even getting them moving the apparatus during the daytime as to basically scaring them nearly to death," Dr. Jay MacNeal, MercyRockford EMS Medical Director, said.

The change comes after an alarming study by Mercyhealth doctors Jay MacNeal and Chris Wistrom. They found with the old blaring tones firefighters heart rates skyrocketed to the 150's and 160's. With the gradual increase heart rates dropped an average of 30 percent.

"The faster your heart beats the less relaxation you have and the less blood supply your blood is getting so the heart actually steals the blood supply from your body to some extent the faster the heart rate goes the harder that becomes," Dr. MacNeal said.

"Making sure that our personnel can retire off the job with a healthy heart is a huge deal," Deputy Chief Murray said.

After the study Beloit Fire installed the gradual alarms in its three stations. Firefighters say they've already noticed a difference.

"I feel not as stressed, not as on edge," Deputy Chief Murray said.

Mercyhealth says this is the first study of its kind. The Rockford Fire Department also has those gradual tones in all of its fire stations.