Be happy, live longer

Turns out, being happy could add years to your life. New scientific findings reveal that seniors who say they are happy have a 35 percent lower risk of dying over a five-year period than unhappy people.

Published online on Monday in the journal Proceedings of the National Academy of Sciences, the researchers gauged the happiness levels of more than 3,800 people ages 52 to 79 by monitoring their feelings four times over the course of a day.

Unlike other "happiness" studies that rely on a participant's recall of emotional states, the researchers used a technique called Ecological Momentary Assessment, which takes a snapshot of what a person is feeling in real time. The scientists then followed them for five years, recording the number of deaths along the way.

Researchers also took into account factors such as the study participants' health, age, marital status, and education level, and controlled for certain medical conditions and smoking habits. Even still, the happier subjects enjoyed longer lives.

"I was a bit surprised that the happiness effect was so strong, even among people who had chronic diseases," study researcher Andrew Steptoe, a professor at University College, London, told MSNBC.

The research supports many other studies that link happiness and a longer, healthier life. One study involved 5,000 college students who were followed for more than 40 years. Researchers found that pessimistic students died earlier than their more optimistic peers.