Why We Make Life-Altering Decisions At Ages That End In '9'

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When I turned 29, I made a couple of life-altering decisions for my life.

I decided that before my 29th year was over, I'd ditch the roommate situation and get my own one-bedroom apartment in the East Village, and I'd quit dragging my feet with the whole writing thing.

I had come to New York City to become a writer, and after five years of office jobs, too afraid to pursue my dreams, it was at the age of 29 that I was finally going to make my move, and did.

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There wasn't anything significant about being 29 really, but there was something definitely very significant about turning 30 and going into a new decade.

At 29, 30 was a scary concept and if I had to enter my 30s, I was going to do it correctly. I can't even imagine what rash decisions I'll make for my life on the brink of turning 40.

But a 2014 study published in Proceedings of the National Academy of Sciences, found that similar to me at 29, people actually do spend their ages that end in nine (like 29, 39, 49) having these sorts of realizations and self-reflections about their lives.

Some of the data from the study revealed that the #1 age that people decide it's time to train for and run their first marathon is the age of 29, with 39 and 49 not being too far behind.

They also found that of the 8 million men on an extramarital affair dating website, Ashley Madison, "more than 950,000 men aged 29, 39, 49, or 59, or nearly 18 percent more than would be expected by chance." 

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And, because websites, like Ashley Madison, that condone you cheating on your husband or wife isn't depressing enough, a study done by the CDC from 2000 to 2011 found that the rate of suicide is higher for the last year of a decade than any other year in that same decade.

What does this mean? Moving into a new decade is scary, and because of it we sometimes do the unthinkable. But why is it so scary?

According to UCLA psychologist, Hal Hershfield, the aging from, say, 39 to 40, is a transition that forces us to take stock in our life and wonder what we can do better in the next decade.

Another suggestion is that at the end of one decade and right on the cusp of a new one, people are often "particularly preoccupied with aging and meaningfulness, which is linked to a rise in behaviors that suggest a search for or crisis of meaning."

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Yes, it's indeed an existential dilemma, and to experience one can really put your ideas on life and humanity through the wringer. But how can anyone be really surprised by this?

Going from 29 to 30 is just as scary as going from 59 to 60 — it's all unknown and just one step closer to the end.

When we're forced to realize the fragility of life, we're forced to make decisions that foster changes.

What did you do during the last year of an age that ended in nine? Make a goal to get engaged by the following year, promise yourself to finally finish that book you've been working on, or maybe even set the bar even higher and plan out how you're going to hike to the top of Mt. Everest in one piece. All of the above?

Honestly, considering how hard it is out there in the dating world, Mt. Everest sounds far easier to swing.

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Amanda Chatel has been a sexual wellness and relationship journalist for over a decade. Her work has been featured in Glamour, Shape, Self, and other outlets.