“A new study is tapping into a phenomenon most of us have heard about and some of us might claim to have experienced at some point – ‘runner’s high.’

“In doing so, this study touches on something fundamentally human.

“Put simply, our bodies were made to move. Our predecessors were long-distance endurance runners who could work really hard, from an energy-expenditure perspective, if it was required.

“Even now, if we really had to, most of us could exert ourselves at a very high level, significantly increasing our energy expenditure, even if was only for a few seconds.

“So why don’t we move more? Why are we facing an obesity epidemic driven largely by sedentary behaviour? How come some people enjoy physical activity more than others?

“Runner’s high – or the idea of it – is one of the things that drives some people to exercise – a neurobiological reward that occurs during and after distance running, creating a sense of euphoria for the athlete.

“This natural high, say some, provides an improved sense of well-being, reduces anxiety, induces post-exercise calm, and can even reduced pain.

“But from a ‘hard-science’ perspective, what is this ‘high’ caused by and does it exist beyond the purely psychological?

“Recent research suggests endocannabinoids (eCB) could be involved and that there’s a direct link between eCB signaling and exercise in humans.

“There are many eCBs but the one that’s been receiving much attention of late is anandamide (or AEA). Research has shown an increase of AEA in plasma levels after moderate intensity aerobic activity (running or cycling).

“Problem solved, right? AEA causes runners high. Slow down, Monoghetti – not so fast. Most of this evidence has been shown in animals other than humans.

“Enter David Raichlen and colleagues who wanted to measure plasma levels of eCBs in two ‘cursorial’ (adapted to, or specialised for, running) species – humans and dogs – and one non-cursorial species – ferrets.

“In their study, published late last week, all species were made to run and walk on a treadmill for 30 minutes continually. They also had their blood taken before and after each of the trials in order to be analysed for eCBs.

“Unfortunately, the ferrets weren’t so keen on treadmill-running so their running trial data was compared with data where ferrets sat quietly in a cage for 30 minutes.

“A questionnaire was used to assess the psychological state of the human subjects before and after all trials.” To continue reading this article, complete with links, from The Conversation, click here.