There’s plenty of data supporting the connection between a positive outlook and a healthier life—being optimistic can help you fend off stress, eat better and be more physically active, all of which can lower your risk of chronic illnesses.
But despite how often it’s repeated, doctors haven’t been able to definitively tell you that a positive attitude will help you live longer, mainly because most studies on the subject haven’t followed people over long enough periods of time. Studies to date tend to ask people about their outlook at one specific time—and the response can be affected by a number of transient events.
So researchers led by Andrew Steptoe at University College of London decided to look at a long-term study to track how people’s outlook over time affected their longevity. In a report published in BMJ, he studied nearly 10,000 men and women in the English Longitudinal Study of Aging between 2002 and 2013.
During that time, the middle-aged volunteers were asked three times to assess their outlook by answering four questions that evaluated how they enjoyed the things they did: being with other people, their lives overall, and how energetic they felt. Nearly seven years after their last answers, people who reported more enjoyment (or the highest satisfaction scores on all three occasions) were 24% less likely to have died than people who reported no enjoyment. Those who said they were happy on two of the occasions had a 17% lower mortality.
“The longer people are in a positive state, the better it probably is as far as their health is concerned,” says Steptoe. “This adds weight to the evidence that outlook might be relevant to health.”
Of course, there are many aspects of one’s outlook—mood, or how happy or sad a person feels is one, as is a broader sense of satisfaction. In past studies, says Steptoe, most researchers captured the mood element, but weren’t able to incorporate the larger sense of satisfaction or well-being. “An emotional state is distinct from finding life satisfying,” he says. “And it’s distinct from having a fulfilled life. The criticism of past studies is that it just looked at the pleasure aspect. So what we are trying to do is to use a measure that cuts across different distinctions.” The four-questions in the study, he says, were designed to do just that.
And how did the people who reported more satisfaction and enjoyment achieve that state of well-being? Previous studies have pointed to things such as good mental health and social connections. Steptoe says that keeping up friendships and maintaining social interactions can be an important part of a satisfying life, particularly for older people. “Once you enter middle and older ages, investment is social relationships is crucial,” he says. “It’s something that is quite easy to forget about. When things are going well, you don’t make so much of an effort to maintain friendships. But in many ways it’s an investment in the future as well as the present.”
This article originally appeared on Time.com.