Researchers have found “clear and compelling evidence” that happiness paves the way to better health and longer lifespans.
The review of more than 160 studies found the evidence connecting an upbeat outlook to a healthier life was even stronger than that linking obesity to reduced longevity.
It has backed previous studies that found a “glass half full” approach was good for your health.
Scientists from the University of Illinois found positive moods reduced stress-related hormones and increased immune function.
Their study, published in the journal Applied Psychology: Health and Wellbeing, found happiness lead to quicker recovery from exercise.
It also concluded that anxiety, depression, and pessimism were linked to higher rates of disease and a shorter lifespan.
People who felt intense anger or lived in stressful environments were more likely to be sick more often and died earlier.
The review looked at eight different types of long-term studies and experimental trials involving both human and animal subjects.
For example, 5,000 university students studied for more than 40 years provided evidence that the most pessimistic students tended to die younger.
In another study, based on 180 catholic nuns, researchers found those who wrote positive autobiographies in their early 20s tended to outlive those who wrote more negative accounts of their young lives.
Animals who lived in stressful conditions, such as crowded cages, had weaker immune systems and a higher susceptibility to heart disease. They also died at a younger age than those in less crowded conditions