Having a positive outlook may protect a person from heart disease, according to a new study.

Researchers at Harvard University believe optimism could cut the risk of a heart attack in half.

They found that optimistic people tend to have healthier blood pressure, cholesterol levels, and weight. These individuals are also more likely to eat well and get enough sleep.

"Sometimes it's hard, particularly in tough economic times, but taking a moment to just relax and enjoy a sunny day might be good heart health," lead researcher Julia Boehm, of the Harvard School of Public Health, said.

Past studies have shown that pessimism causes stress, which can lead to artery damage and heart problems.

The review, funded by the Robert Wood Johnson Foundation, was published Tuesday by the Psychological Bulletin.