A recent article in Applied Psychology: Health and Well-Being reviewed more than 160 studies of how happiness affects human and animal subjects. Lead author, Ed Diener, Professor emeritus of psychology at the University of Illinois, offers overwhelming evidence to support the idea that happier people live longer and healthier lives. The review analyzes eight different types of studies. This includes a study of almost 5,000 university students for more than 40 years, a study of 180 Catholic nuns from early adulthood to old age, and animal studies which show a strong correlation between stress and poor health. There were exceptions, but overall the researchers found that anxiety, depression, pessimism, and lack of daily enjoyment were all associated with higher disease rates and a shorter lifespan. “I was almost shocked…to see the consistency of the data,” Diener said, “All of these different kinds of studies point to the same conclusion: that health and then longevity in turn are influenced by our mood states.” Diener also believes that the evidence showing positive emotions lead to a longer life, is stronger than the data linking obesity to reduced longevity. Current health recommendations only focus on avoiding obesity, eating right, not smoking, and exercising; Diener states it may be time to add a fifth: happiness.