A slight running theme of late I’m afraid. The reason? I’ve started to revise for my exams. Most people find this particularly tiresome, but for someone who rarely stops to sit down it is bordering on depressive for me. Running gives me a chance, not only to clear my head, but it also lifts me, makes me happier.
Contrary to what many think, I don’t really enjoy the actual process of running all that much. I hate the feeling of your entire body aching as your feet repeatedly hit the pavement, your lungs straining to inhale enough air whilst beads of sweat slowly roll down the sides of your face. The heat of the recent days makes this particularly bad; running through London’s parks and along the Thames leaves you covered with a layer of grime. It’s not a pleasant experience! Having said this, I do actually like running… a cold glass of water and a shower later, I am left with a sense of euphoria, the ‘runner’s high’.
Many people talk about getting an endorphin rush when they do exercise, but what is an endorphin? And can they cause this natural high? I came across a pilot study published in 2008, ‘The Runner’s High: Opioidergic Mechanisms in the Human Brain’ which gave me a few pointers.
The word endorphin is derived from two words, endogenous and morphine, because these hormones act similarly to morphine (a natural opiate) within the natural opioid system in the nervous system. They were discovered in the mid-1970s and are produced by the pituitary gland and the hypothalamus during exercise (and others times of euphoria ;)).
The endorphin hypothesis was put forward as a possible explanation for the runner’s high when it was noted that endorphin levels were raised in blood samples and cerebrospinal fluid, and that this correlated with changed in mood. However, and importantly, raised levels of endorphins in the periphery doesn’t necessarily correlate with raised levels in the brain. The aim of the study I came across was to unravel whether strenuous exercise raised endorphin levels in the brain, and whether they could be associated with mood elevation.
The three different types of endorphin bind with different affinities to opiod receptors in the central nervous system. Through examining the availability of these receptors, i.e. whether there was any endorphins bound to the receptors or not, the study showed that when the receptors were less available in certain areas of the brain – the prefrontal, limbic and paralimbic brain regions – athletes felt a sense of euphoria.
This led the authors to conclude that “this study provides first in vivo evidence that release of endogenous opioids occurs in frontolimbic brain regions after sustained physical exercise and that there is its close correlation to perceived euphoria of runners. This suggests a specific role of the opioid system in the generation of the runner’s high sensation.”
A lot more research needs to be done to investigate this further, but this gives some valuable insight into the neurochemical mechanism of the runner’s high.
Reference: Boecker , H et al. (2008) “The Runner’s High: Opioidergic Mechanisms in the Human Brain” Cerebral Cortex November 18:2523-2531