Are you happy? After reading this you might want to smile more.

Thanks to Rita Watson, an associate fellow at Yale’s Ezra Stiles College. She recently highlighted several scientific investigations on happiness. They bode well for how we age:

– The European Heart Journal recently published the findings of Dr. Karina Davidson of Columbia University Medical Center. Her team followed 1,739 people for 10 years participating in the Nova Scotia Health Survey. Their findings: Happier people are less likely to develop heart disease than crabby ones.

– A study at the University of Kentucky involved 124 first-year law students tracked over four years. The findings, in the March Psychological Science, noted that in each individual, optimism was reflected by strong cell-mediated immunity. Just as our bodies send cells to fight infection when we have a cut or wound, optimism helps us stay healthy.

– Alzheimer’s prevention was reported in the Archives of General Psychiatry recently, with a study of 951 "community-dwelling older persons without dementia from the Rush Memory and Aging Project in areas around Chicago. Dr. Patricia Boyle and her team found that those who had a greater purpose in life had a reduced risk of Alzheimer’s and milder cognitive impairment