There’s a myth that many young men in Japan are familiar with: the physical exertion involved in one ejaculation is the same as running 100 metres as fast as you can. Now, although many such claims often carry about as much scientific weight as the idea that dropping a cold key down someone’s back can cure the hiccups, as any men will tell you, there’s a reason why we often feel the need to collapse and fall asleep after a particularly vigorous session.

Nonsense or not, this particular myth is one that has existed for generations in Japan and refuses to die off, being passed from one huddle of teenage boys or young office workers to the next. For this reason, online magazine R25 turned to a medical professional to get the cold, hard facts.

“The male orgasm supposedly burns the same amount of calories as running 100 metres with all your might,” the magazine begins. “By this logic, ejaculating three times would require the same amount of calories as a 300-metre run, and five times 500 metres’ worth, meaning that doing it 10 times would be about on par with a long distance run.”

These figures all seem somewhat vague and conveniently neat and tidy, however, so the magazine asked Dr. Ryukou Suda from the Shinjuku Life Clinic to shed some light on the old schoolyard tale.

“This is an incredibly difficult thing to measure since there is no fixed standard for the amount of energy required for a single ejaculation,” the good — and clearly very patient — doctor explains. “At either end of the spectrum, the amount of energy burned during a bout of extremely athletic sexual intercourse differs greatly to that required during a relaxed solo session.”

So there’s no way to know? How will we ever survive as a species without the answers to daft questions such as these!? Thankfully, Dr. Suda goes on to elaborate, pointing us in the direction of good-old science.

Apparently, by using Metabolic Equivalent of Task (MET) calculations, we’re able to ascertain how much energy a man burns during hanky panky. This measurement is often used when calculating the amount of physical exertion a person who has suffered a heart attack ought to limit themselves to, with each task being given a MET “score”. We can use METs to calculate the amount of energy used in a number of physical activities, Dr. Suda explains: “Regular walking costs between 3.0 to 4.0 METs, and jogging around 7.0. Averagely strenuous sex comes in at around 1.3 METs. So in other words, on the scale of exertion, it wouldn’t be possible to use as much energy in one ejaculation as flat-out sprinting.”

There you have it, folks; science has the answers. But then why, if the number of calories burned during sex is so much lower than strenuous activity like sprinting, should so many of us men slump over with all the life and enthusiasm of an empty pillow case seconds after we’ve released the doves? Perhaps it’s just down to feelings of sheer elation and gratitude that someone actually let us climb aboard for a spot of numpty…

Source: R25