Put your conversation skills to the test this World Happiness Day.

Building good relationships with colleagues, or ‘social fitness,’ isn’t only important for getting work done, but can also help you live longer.

Happiness has nothing to do with money, schooling or life. The relationships you build with others have a direct impact on your happiness.

When scientists began monitoring the health of 268 Harvard students, including future U.S. President John F. Kennedy, in 1938 during the Great Depression, they thought that long-term research would provide clues to a healthy and happy life.

Body, exercise, diet, schooling, and how much or how little money one earned or did not earn had nothing to do with satisfaction.

The 85-year-old Harvard study discovered a strong link between happiness and intimate relationships with people such as partners, family, friends and co-workers. According to the study, people who were most satisfied in their relationships at age 50 were healthiest at age 80. The researchers called building and maintaining these networks that keep us satisfied “social fitness” and considered them actions that “help us live longer and happier.”