Love and happiness may not actually originate in the heart, but they are good for it. For example, a 2005 paper found that happiness predicts lower heart rate and blood pressure. In the study, participants rated their happiness over 30 times in one day and then again three years later. The initially happiest participants had a lower heart rate on follow-up (about six beats slower per minute), and the happiest participants during the follow-up had better blood pressure.
Do you know a grumpy person who always seems to be getting sick? That may be no coincidence: Research is now finding a link between happiness and a stronger immune system.
In a 2003 experiment, 350 adults volunteered to get exposed to the common cold (don’t worry, they were well-compensated). Before exposure, researchers called them six times in two weeks and asked how much they had experienced nine positive emotions—such as feeling energetic, pleased, and calm—that day. After five days in quarantine, the participants with the most positive emotions were less likely to have developed a cold.