Heart disease patients who have a positive attitude are more likely to exercise and may live longer, according to a study published in the journal Circulation: Cardiovascular Quality and Outcomes.

According to the researchers from Denmark, previous studies have shown that a positive mood has been linked with better prognosis in patients with ischemic heart disease, but how this works has been unclear.

For this study, the researchers set out to determine whether "positive mood affect" was able to predict the length of time between the first cardiac-related hospitalization and all-cause mortality, and whether exercise would play a part in mediating this link in patients with ischemic heart disease.

The researchers analyzed 607 patients suffering from ischemic heart disease over a 5-year period.

All patients were asked to complete a questionnaire disclosing their level of exercise and a Global Mood Scale questionnaire in order to determine their mood and attitude over the study period.

Results of the study showed that the patients who had a more positive attitude exercised more and had a 42% reduced chance of death for any cause during the follow-up period.

In patients who were more positive, the death rate was 10% during the study period, compared with 16.5% in patients who were less positive.

Additionally, patients who had positive moods and exercised more also showed a reduced risk of heart-related hospitalization.

The study authors explain:

"We found that patients with higher levels of positive affect were more likely to exercise and were at lower risk of dying during 5 years of follow-up, with exercise mediating the relationship between positive affect and mortality, independent of demographic and clinical risk factors."

The researchers say that interventions are needed to encourage a combination of a "positive affect induction" and exercise. They point out that this could result in better outcomes for patients in terms of maintaing a healthy exercise regime and promoting better psychological functioning, compared with focusing on exercise regimes alone.

Susanne Pedersen, professor of cardiac psychology at Tilburg University in the Netherlands, says:

"We should focus not only on increasing positive attitude in cardiac rehabilitation, but also make sure that patients perform exercise on a regular basis, as exercise is associated with both increased levels of optimism and better health."

The researchers conclude that future studies should concentrate on the development of such interventions, which are specifically aimed at patients with ischemic heart disease.

Research from Duke University Medical Center in 2012 found that exercise may reduce symptoms of depression in patients suffering from heart failure.