Erectile dysfunction, which typically focus on a man's inability to have sex, has a more devastating issue that could be behind having difficulty maintaining an erection - heart disease, researchers say.

Research has connected erectile dysfunction with heart disease in men between the ages of 30 to 60 for years, but it is still not commonly known among the public.

"You hear about men who pass away from heart disease and their wives find Viagra [in their belongings] and they didn't even know they had a problem," the Huffington Post quoted Dr. Kevin Billups from Johns Hopkins Hospital's Integrative Men's Health Program as saying.

According to doctors, for many men experiencing erectile dysfunction is the first signal of risk factors which, if unchecked, can lead to heart disease.

"The likelihood of having heart disease at some point is two to three times higher in those who have ED than those who don't," Dr. Mehdi Shishehbor, a cardiology specialist at Cleveland Clinic, said.

The question that needs to be answered is why would a problem affecting your penis signal a larger problem with your heart?

"The penile arteries are much smaller than the arteries that supply blood to the heart, brain or lower extremities, and will block faster, Dr. Billups said.

"Erectile dysfunction will often appear as a symptom years before the heart attack. The other reason is that the penis is more sensitive [than other organs] to early changes associated with increased risk of heart disease, such as inflammation and oxidative stress," he said.

Coronary heart disease occurs when the arteries around the heart harden and narrow, making it more difficult for much-needed blood to reach the heart muscles.

A number of variables including high cholesterol, hypertension, smoking and diabetes cause this hardening, which can lead to chest pain or even a heart attack.

"The same process can happen in the pelvis," Dr. Shishehbor said.

"The same risk factors that apply to coronary artery disease are the same risk factors that apply to blockages in the penis. Over the years blockages form and prevent blood from getting to the penis. In order to get an erection we need blood flow to the penis.

"As you age and if you don't take care of your risk factors -- if you smoke, don't eat healthy, don't control your blood pressure.

"Those things can lead to the same process that leads to blockages in the heart and can cause blockages in the penis," Shishehbor added.