I did a long interview recently on smiling for Shape Magazine that will come out in a few months.
I did research on smiling when I wrote my book, "Success Signals," and more research as the National Spokesperson for the Natural Dentist products, Yes, I know about a ridiculous amount of research on smiling.
In this cold and flu season, I advise you to start smiling and don't stop till spring. Smiling can help you fight off a cold and boosts the immune system. While smiling, your body relaxes and so your immune system reacts more quickly and effectively against invaders. The Department of Clinical Immunology at Loma Linda University School of Medicine found that, when smiling, the serum cortisol levels (stress level) decrease and, instead, the number of white blood cells and natural killer cells increases. So if you want to fight off a nasty cold in the future, forget going to the pharmacy, Just Smile!