Big changes come at the end of decades--for better or for worse. Individuals whose ages ends with 9 are more likely to seek extramarital affairs, run marathons and commit suicide compared with those whose ages ended in other numbers.

Researchers from both New York University and University of California, Los Angeles conducted six studies to see how people in the last year of their 20s, 30s, 40s and 50s changed their behavior. The team was able to find through their analysis that people with ages ending in 9 (who the researchers called “9-enders”) were more likely than others make extreme decisions.

"When people are facing these new decades, that's when they start to step back and question essentially the meaningfulness of their lives," said study co-author Hal Hershfield, a marketing professor at UCLA. "We're not saying people don't do that at other points in their lives. Just that it's particularly likely to happen during life transitions."

One positive to come out of this study is that “9-enders” ran faster marathons than people two years younger or older, which shows they trained harder.

Experts suggest those approaching an age milestone consciously set positive goals in order to avoid reacting negatively. A marathon or even a half-marathon can be the perfect example of one. What are some other great goals for “9-enders”?



ABC News: Birthday Years Ending in 9 Prompt Big Life Decisions, Study Shows