Men in mid-life who take good care of themselves and keep off the weight are far less prone to developing heart disease -- however, if they develop erectile problems they could also have metabolic syndrome, an early developmental stage of heart disease.

The newest study found that men with body mass index (BMI) measurements lower than 25 -- which is normal weight -- who developed erectile difficulties, were twice as likely to develop metabolic syndrome. Men in the study with a BMI over 25 seemed to have no association between erectile dysfunction and the heart disease precursor. Metabolic syndrome includes such symptoms as high blood pressure, high blood fat levels, weight gain around the abdomen and poor regulation of insulin.

Researchers have found that sildenafil citrate, known as Viagra, minimizes by 50 percent the chemically-induced stimulation of increased rate and pumping force of the heart caused when stress hormones in the body rise. Stress hormones can rise under emotional or exercise stress, or when there is heart failure. Originally prescribed for erectile dysfunction (ED) in men, Viagra appears to have a direct effect in protecting the heart against the short-term intense assault of stress hormones. The benefit Viagra gives in controlling heart function kicks in when stress hormones increase, but has little affect on the heart under normal conditions.

According to the researchers of this study, separate research published last year in the journal Nature Medicine showed that, in mice, Viagra could reverse the negative effects on heart muscle weakened by heart failure and enlargement, a condition called hypertrophy. "But we had no firm evidence as to whether or how this therapy might work in the human heart. Our latest research provides firm evidence this drug does indeed have an important impact on the heart," states cardiologist David Kass, M.D., professor at The Johns Hopkins University School of Medicine and its Heart Institute.

"Knowing more about the effects of sildenafil on heart function will allow for  safer evaluation of its use as a treatment for heart problems," says Kass. "Until now, it was widely thought that drugs like sildenafil had no effects on the human heart and that its only purpose was vasodilation in the penis and the lungs." He believes the results of this study will open the door to further studies into the potential benefit of Viagra on the heart. You can find more information about the study here.