Dial 9 for your life change

"We found that at nine-ending ages, people tend to question whether their lives have been meaningful," says study co-author Adam Alter. Image via Shutterstock

Midlife crisis? More like an end-of-the-decade crisis. Research from New York University shows that people aged 29, 39, 49 or 59 are more likely to make radical moves – both positive and negative – such as starting a serious exercise program or considering an extramarital affair.

"We found that at nine-ending ages, people tend to question whether their lives have been meaningful," says study co-author Adam Alter. "That can be an overwhelming psychological experience, particularly if they don't feel their lives are meaningful enough."

Men who had an age ending in nine were particularly at risk of potentially self-destructive behaviour, with the researchers finding they were much more likely to register for an extramarital dating site than men of other ages.

Approaching your own "date with destiny"? Alter advises not putting too great a significance on the end of a decade. "In truth, the difference between 29 and 30 is no more meaningful biologically than the difference between 28 and 29 or between 30 and 31," he says. “At the very least, it's worth pausing to consider whether your decision is motivated by a genuine need or rather by the symbolic passage from one decade to the next."