Archive for February, 2018

The runner’s high, the ‘zone’, and ‘second-wind’

February 7, 2018

This post will explore what modern neuroscience has to say about some of the mental phenomena that occupy a tantalising place in runners’ folk-lore: the runner’s high, the zone, and ‘second-wind’.   On the one hand, popular folk-lore accepts that the mind is just as important as the heart and skeletal muscles in athletic performance.  We accept the grain of truth in Yogi Berra’s incongruous quip:  “Baseball is 90 per cent mental. The other half is physical.”  In recent years the topic of sports psychology has taken up an increasing amount of space in running magazines.  On the other hand, most of us devote more attention to the question of the best way to train heart and skeletal muscles, than to the training of our minds.   Perhaps this neglect of the mind is a pragmatic response to the scant evidence that is available to guide the training of the mind.  Many of the recommendations of sport psychologists, such as the need for positive self-talk, are quite plausible in themselves but appear too simplistic to account for the runner’s high; or the transcendental experience of being that mystical zone where power is achieved effortlessly; or the second wind that inexplicably revitalises us when we are struggling to maintain our pace.

However in recent years psychology has been transformed by the advances of neuroscience. This does not mean that describing mental processes in terms of brain processes replaces the value of understanding mental processes in terms of more traditional psychological concepts: concepts such as confidence, motivation and will-power. Mind and brain are two equally valuable sides of one coin.  We now understand a lot about the ways in which the mind can shape the brain just we understand how the brain can shape the mind.  But in contrast to the less tangible tools of traditional psychological science, neuroscience provides tools for objective measurement.  It adds a new dimension to our understanding of the mind, and holds promise of a solid foundation for developing effective ways of training our minds.

But despite the potential power of neuroscience to provide reliable answers to our questions, the sheer complexity of the human brain should warn us to be careful to avoiding invest too much faith in the preliminary findings in our investigations.   With that word of warning, let us begin our exploration of this field (though perhaps ‘forest’ would be a more realistic term) with an illustration of the power of the mind from the 2017 London marathon.

Kenensa Bekele, who had started as one of the pre-race favourites, appeared to be a spent force with 7 miles still to run, and then staged an awe-inspiring resurgence that got him almost within touching distance of the break-away leader Daniel Wanjiru as they ran along the Embankment with less than 2 miles to run.  Surely something powerful happened in his mind to generate Bekele’s dramatic ’second-wind’.   Perhaps equally importantly, what mental force sustained Wanjiru while he maintained the punishing average pace of 4:43 min per mile in the 12th to 16th miles that shattered the morale of the elite field.  Then as Bekele closed the gap along the Embankment, Wanjiru was able to step up the pace again.   This was an epic battle between two runners with superlative physical fitness, but also with immense mental strength.


A re-vitalised Kenenesa Bekele (right) pursuing Daniel Wanjiru along the Embankment in the London marathon, 2017

It is tempting to equate mental strength with the ability to persist despite pain.  However, this simplistic description is misleading. Pain is a protective signal indicating the need to take avoiding action to prevent damage to the body.  But this definition fails to address the fact that the experience of pain depends on many aspects of the situation including past experiences, current circumstances and future expectations.   Developing mental strength is not merely a matter of gritting ones teeth.

What insights might neuroscience offer?    Multiple brain circuits are likely to be involved, most especially the circuits making up the limbic system deep in the brain, and paralimbic cingulate gyrus lying on the brain’s medial surface, and the insula cortex, buried in a deep fold hidden by the temporal lobe (see figure 2). These circuits play key roles emotion, motivation, and in the evaluation of the signals from within the body.  The neurotransmitter, glutamate, mediates long-range communication in these circuits, while various other neurotransmitters play a modulatory role, adjusting the tone and intensity of signal transmission.  Three groups of the modulatory transmitters play an especially important role in the response to stress and pain: catecholamines, endorphins and endocannabinoids.

Insula and Limbic system

Figure 2: The insula and limbic system. The insula lies in a fold of cortex hidden between the medial temporal lobe, containing the amygdala and hippocampus, and the deep grey nuclei, which include the basal ganglia (not shown) and the thalamus.


Catecholamines: noradrenaline and dopamine

The two principle catecholamines in the human brain are noradrenaline and dopamine. Noradrenaline is similar to adrenaline, the hormone that acts rapidly to mobilise the body’s resources when we face any form of acute stress.  In the brain, noradrenaline  mediates arousal by increasing the overall tone of brain activity.   Dopamine plays a specific role in mediating motivation to act.  It mediates the experience of reward for beneficial actions. It plays a key role in the learning of beneficial patterns of activity.   If dopamine is depleted we become listless and lethargic.  Illicit stimulant drugs such as cocaine and amphetamine promote excessive release of dopamine, generating an unnatural surge of energy.


Endorphins have attracted the popular imagination because they are the brain’s natural opiates.  The concentration of endorphins in the blood increase during exercise.  However this observation provides only limited evidence for the hypothesis that endorphins play an appreciable role in the brain during exercise.  First of all, endorphins are large molecules that cannot pass across the barrier that exists between blood and brain and therefore, observed increases in blood levels do not necessarily correspond to brain levels.   Secondly, the two main side effects of opiates: respiratory depression and constipation are not observed during running.    Thus there is little direct evidence that endorphins play a substantial role during running.


Endocannabinoids are produced naturally in the body, and bind to the cannabinoid receptors that bind the cannabinoid chemicals such as tetrahydrocannabinol (THC)  derived from marijuana. The binding of endocannabinoids to these receptors in diverse tissues of the body produces a wide diversity of effects.  In the lungs, endocannabinoids produce bronchodilation, opening the airways to allow easier flow of air into the lungs.  They also exert anti-inflammatory effects.  Endocannabinoids are fat soluble and can easily pass across the membranes that separate blood from brain.   In the brain they produce a mental state characterised by euphoria, a sense of well-being and distortion of the passage of time.  These effects are similar to the mental experience described as being in ‘the zone’.  Furthermore endocannabinoids interact with the dopaminergic system in a complex manner.  In particular they can enhance the release of dopamine in the basal ganglia thereby enhancing the experience of reward.  It is noteworthy that laboratory animals lacking the gene for the endocannabinoid, anandamide, exhibit profound under-activity.

The central governor revisited

The evidence regarding the role of endocannabiniods during exercise adds intriguing subtlety to Tim Noakes’ concept of the central governor that sets the limit on how hard we can push ourselves during exercise.   This new evidence suggests that the brain does not merely passively accumulate warning signals from the body, and dictate a shutdown when we reach a pre-set threshold at some fixed ‘safe’ percentage of our maximum physical capacity.   Instead the evidence suggests that the decision whether or not to persist with an action depends on a more complex balancing of information.

The role of dopamine in facilitating reward seeking behaviour suggests that the conservative influences that promote the avoidance of harm are balanced by adventurous impulses that encourage us to seek excitement or exhilaration.   Perhaps during our evolutionary past our forebears developed a conservative tendency to discourage them from wasting energy pointlessly when food was hard-earned and metabolic energy was a resource to be husbanded prudently.  On the other hand, the need to acquire skills and keep them well-honed demands engagement in activity for its own sake: prudence should be leavened with playfulness.

When energy resources were at a premium, in ordinary circumstances the threshold at which the balance tipped against continuing activity was likely to have been far below the level at which activity was immediately dangerous.   At times of danger, when our forebears were at risk of becoming prey, or perhaps during a hunt, when they became the predators, the threshold could be re-set.  The sympathetic nervous system, which releases adrenaline to stimulate heart and lungs, and noradrenaline to arouse the brain, provides a rapidly acting mechanism capable of the required rapid mobilisation when danger is acute; in contrast, it appears that the endocannabinoid symptom is well suited to promote sustained increases in work output during a prolonged hunt.   For many of us nowadays, energy resources are plentiful and it is plausible that our brains which had evolved in more stringent circumstances, tend to set the threshold for equipoise between benefit and harm at an unnecessarily low level.

While this reformulation of the central governor hypothesis is speculative, it does offer a plausible explanation of why evolution has provided us with several distinguishable though interacting systems for mobilising our bodies.  Whatever the details of the roles of the various components of these overlapping systems, the crucial point is that to achieve maximum athletic performance, we must not only train to develop our peak physical capacity (for example by maximizing VO2max) we also need to develop the capacity to re-set our naturally conservative threshold for shutting down the system.

It is nonetheless necessary to bear in mind that our brain is designed to shut down the system when the risk of harm is high.  However provided we are in good health, it is likely that there is a large margin between our naturally conservative threshold and the maximum safe threshold. It should be noted that the increase in endocannabinoids during exercise is usually substantially less than the increase that is achieved by smoking forms of marijuana with high THC content, such as ‘skunk’.  We are unlikely to come to harm if we only invoke our own endogenous neuromodulators, .

How can we train  in a way that enhances our capacity to raise a naturally conservative threshold that is inclined to shut down the system prematurely?  This is the question I will address my next post in this series.