How long is sex actually supposed to last? You hear all the stories about the time it was over in under a minute (better luck next time), and then there's the type where it's an hours-long session and you wonder where people get their stamina.

But science has clarified this one for us because one particular psychologist has dedicated a large chunk of his professional life to studying how long heterosexual couples tend to have penetrative sex for.

Defining "sex" as the time from penetration to ejaculation, psychologist Dr. Brendan Zietsch from the University of Queensland politely asked 500 couples from all around the world to invite a stopwatch into the bedroom across a four-week period, documenting exactly how long it lasted.

And the results were, shall we say...varied. With timings ranging between anything from 33 seconds to 44 minutes (damn), Dr. Zietsch took an average of the couples' results, and it worked out to be 5.4 minutes. Which somehow seems a little less than you'd think, but then both time and context escape you when you're in the throes of sex, don't they?

Where you are in the world didn't seem to have much of an impact on the duration of sex. But the exception to that was couples from Turkey, who seem to prefer a 'wham, bam, thank you ma'am' scenario, with their average time coming in at a notably shorter 3.7 minutes.

Age was obviously a factor, with younger couples managing to last for longer. No surprises there.

But what's perhaps most interesting is why we last the amount of time we do. Apparently, it's all to do with the shape of the penis.

A study dating back to 2003 used fake vaginas and penises, as well as fake sperm made from corn syrup, and discovered that the ridge around the head of a penis can scoop out syrup (semen) that's already inside the vagina. It's thought that—as a basic instinct—men need to thrust for long enough to remove another man's sperm from inside the woman before they leave their very own nice little deposit. Or, you know, it could just be a case of getting the right angle and pace. 

From: Cosmopolitan UK