The lull in anatomy ended several months ago. This only means my days have once again been filled with reading – reading books, re-reading books, and weeks of days spent delving into the far reaches of the internet in search of the latest revelations on the runner’s brain.

It would be a fair assumption to think this post will ooze facts about all the positive benefits running gives back to your brain. Those benefits are indeed countless and noteworthy, but my curiosity lies more in what the brain contributes to our running, or our capacity to keep running. In other words, has anyone confirmed whether the brain controls or limits endurance?

Early studies concluded it was the heart itself that became fatigued, which resulted in too little blood being supplied to the skeletal muscles and brain. Running all out at our fastest pace for several minutes could make us all support this theory, but the heart does not fatigue. This realization led to the idea of a ‘governor’ that terminates exercise before maximal blood flow to the heart is achieved rendering the heart damaged. The supporting data suggested that a governor somewhere within the body does terminate exercise before the heart and skeletal muscles are forced to contract anaerobically (without oxygen). These notions persisted and evolved for a long time.

The central governor theory has ultimately come under attack with compelling arguments. One scientist observed that with the exception of combat activity, sport is perhaps the brain’s biggest challenge, requiring more cognitive skills than is often appreciated.

The ability to plan and execute performance, make corrective adjustments to behaviour (e.g., modify skill execution or pacing strategy), resist temptation, manage emotions, elevate collective obligations above myopic self-interests, and persevere despite disappointment all constitute acts of self-control (or self-regulation) implicated in successful sports performance (Friesen, Devonport, Sellars, & Lane, 2013; Hardy, Jones, & Gould, 1996; Tamminen & Crocker, 2013). This is one of the lines of thinking that gave us a new term, ego depletion, and a string of new theories about the limitations of endurance.

I’ve contemplated abandoning the brain several times. There are other anatomy posts I could churn out in an afternoon, and I’d much rather move on to the creative side of writing. But, I can’t let the brain go, so I continue to needle my way through theories of endurance.

It was a breakthrough day when I came up with an outline from the 25 pages of research notes I had collected. Then I found a thesis written in 2016 by a Doctor of Philosophy student at the University of Wolverhampton. The author presented research from four studies that examined self-control in sport, and co-authored two additional studies that explored emotion as a factor in the self-regulation of endurance.

The best news of this discovery was that it’s written in plain English, and presents the studies and opposing arguments of the studies already in my research notes. Even better, all of the studies’ control subjects were athletes, and in one case they were competitive endurance runners. The bad news of this discovery is that the thesis is 292 pages long. The reading phase begins again.

My husband reminded me one day how few people experience the feeling of pushing their body to the point that the brain would shut them down. It’s a humbling experience that almost always leaves the athlete more confident and empowered.

I presented several questions in a previous post about the heart: Do the muscles fatigue and reduce their output because the body has reached its maximum potential to deliver oxygen? Does the heart force the muscles to reduce output because it senses a lack of blood flow (oxygen) and works to protect itself? Or, does the brain anticipate when the blood and oxygen supply to the heart is about to become inadequate, reducing the recruitment of the muscles to diminish or cease exercise altogether (fatigue) before damage is incurred to the heart or skeletal muscles?

Even if we acknowledge the body’s central governor must be found in the brain, and thereby controls the mechanisms that dictate endurance, this simply raises more questions. Stress, will-power, emotion, fatigue, motivation, the placebo effect, and even personality traits originate in the brain and each one contributes to, or limits endurance. . . the brain is still under construction.