You don't need to read about yet another study proving how fantastic exercise is for your mental health and well-being. Scientists already understand there's a strong link between happiness and physical activity.

What wasn't known, however, is how the two are linked. Does exercising make people happier, thus producing positive effects on their psychological well-being? Or are happy people more likely to exercise, which keeps their brains happier and healthier for longer? Scientists have long pondered these same questions. The results from an 11-year study conducted by researchers at Chapman University reveal what's happening in the brains of those who stay active later in life.

The study examined levels of physical activity of nearly 10,000 adults aged 50 and older. Over the course of 11 years, participants were asked to rate their physical activity as sedentary, low, moderate or high. Throughout the study, researchers compared their physical activity to their levels of psychological well-being.

Better mental health leads to more physical activity

The researchers found those who had a higher psychological well-being at the start were more likely to stay physically active throughout. And those who were already active at the beginning and had high levels of psychological well-being tended to stay active even as they got older.

There's a key reason researchers were so interested in studying this group. Essentially the longer you're able to stay active, the better your chances are for living longer. Physical activity later in life can help reduce the risk of heart disease, improve cognitive function and keep people healthier for longer. With this study, researchers wanted to uncover what might be the best motivator to keep an aging population physically active.

They concluded that targeting an aging patient's mental health to increase happiness could be the best preventative measure for a longer live. Based on the results, Julia Boehm, Ph.D., and lead author on the study, concluded that improving a patient's mental well-being could have two-fold effect. Not only would improved mental health improve their happiness, but it could naturally lead to higher levels of physical activity.

"Results from this study suggest that higher levels of psychological well-being may precede increased physical activity; therefore, it is possible that psychological well-being could be a novel way of not only enhancing psychological health but also increasing physical activity--which in turn could improve the physical health of a large segment of people in an aging society."