If you’re about to turn 29, 39, 49 or 59, then get ready for some life changes—some likened to a reawakening and others resembling that of a quarter- or mid-life crisis.
Researchers from the World Values Survey analyzed the responses of 42,000 adults from more than 100 countries who completed a survey on their values between 2010 and 2014. They found an interesting trend: people with an age ending in "9" reported thinking and questioning the meaning of life more than any other age group.
At milestone birthdays, people either conclude that their lives are meaningful, or they decide their lives lack meaning. Some engage in productive behaviors like taking up a new sport or running a marathon for the first time. In fact, researchers suggested the “9-enders” were found to be more motivated and trained harder in marathons than any other participants; people ran an average of 2.3% faster in their 9-end year than the two years before or after.
In contrast to the adaptive behavior, other 9-enders were prone to behavior that suggests a “crisis in meaning.” Researchers obtained data from an online dating site that targets people who are already in a relationship and found there were 18% more 9-ender men on the site than expected by chance. Hey, no one ever said going over the hill meant the grass would be greener.