All of us feel better when we are happy, and now medical science is exploring the health benefits of positive emotions. A recent review of more than 200 studies has found that positive psychological well-being is linked to less risk of heart disease, lower blood pressure, normal body weight, and overall good health. The studies also showed that among those 60 and over, feelings of happiness and enjoyment were associated with improved mobility and a lower risk of developing a disability. It's even been scientifically proven that happiness can alter your genes. A team of researchers at the University of California (UCLA) showed that people with a deep sense of happiness and well-being had lower levels of inflammatory gene expression and stronger antiviral and antibody responses. This falls into the realm of epigenetics – the way that our emotions can change the functions of our genes by turning them off and on.

The evidence shows that people who are happy are less impacted by everyday stressors, and this ability to deflect stress is responsible for many of the gains in their health. Several researchers have discovered that positive emotions – including being happy and calm – appear to play a role in immune function. One study found that when happy people are exposed to cold and flu viruses they are less likely to get sick, and if they do become ill they have milder symptoms. The lead researcher of the UCLA study summed it up this way: "We need to take more seriously the possibility that positive emotions are a major player in disease risk."