If you’ve ever trained for a race or participated in a physically demanding sport, you’ve no doubt hit the proverbial wall: the physical and mental inability to keep running, biking, or otherwise continue the grueling activity. Your lungs burn, your muscles throb and strain, and you’re 100 percent sure that your weak, exhausted body can go no further. But whereas you assume your energy reserve has long been tapped, there are others, like exercise and sports science professor Tim Noakes, who believe you’ve got more to give.
Back in 1997, Noakes put forth an idea (based on previous work by a Nobel Prize–winning physiologist in the 1920s) that he called the central governor (CG) theory, which suggests that the brain keeps the body from dipping too low in energy by tricking it (via pain signals) into feeling fatigued. But does that mean that the clichéd phrase “mind over matter” could actually be true? When you think you’ve reached your absolute physical limit, is it possible you’re being fooled?
Mentally vs. Catastrophically
The CG theory challenges the more accepted theory regarding fatigue, which is called either the cardiovascular/anaerobic (C/A) model or the catastrophe model. It proposes that exercise exhaustion stems from physiological processes, such as too much lactic acid buildup in the muscles, too little oxygen, and so forth. Proponents of this theory believe that the body tells the brain when it’s time to take a break, whereas Noakes and his followers argue that it’s the other way around. That’s why the idea of a “central governor” is fairly controversial in the sports science world: it dismisses established beliefs about the human body in relation to physical exertion, such as the notion that a person’s maximum oxygen intake correlates to his physiological fitness. (CG supporters question whether we can even truly measure our physiological limits, since they’re controlled by a largely unconscious force.)
There’s no question that the body reaches a certain point, energy-wise, at which it can no longer function. Think about marathon runners who collapse near the finish line, literally paralyzed or shaking too much to go on. (In more scientific terms, they experience a “physiological catastrophe.”) And that’s what those who stand behind the C/A model point to when criticizing the notion of a central governor. But Noakes and his colleagues at the University of Cape Town, the primary researchers behind the theory, also use marathon runners as examples of how the human body can push past perceived physical restraints. In a 2007 Sports Medicine article outlining his theory, Noakes discussed how race participants can actually run faster once they’re near the finish line, even if they feel utterly depleted before that. (Since the brain recognizes that the end of exercise is near, it allows a little extra energy from its hidden stash to be released.)
A 2007 study out of the John Rankin Laboratory of Pulmonary Medicine found that exhaustion is, to some extent, a mental condition. After conducting three trials of cyclists biking at varying degrees of exhaustion, researchers found that, though their performance varied as well, the amount of muscle fatigue remained the same each time. They concluded that the fatigue was “confined to a certain level,” suggesting that the brain doesn’t allow muscles to tire past a point, regardless of how fast or powerfully they’re working. Another study, this one published in a 2009 edition of the Journal of Applied Physiology, also discovered a surprising link between the mind and exhausted body. They had volunteers ride stationary bikes after doing one of two things: watching a documentary or working on a task that required attention and memory work. It turns out that the ones who did the mental task reached a point of physical exhaustion an average of 15 percent earlier than the mentally rested exercisers—even though their measured heart and muscle work levels were the same.
A 2009 study published in the Journal of Physiology might even be more telling about the brain’s mysterious doling out of energy. Researchers asked cyclists to bike while swishing either a placebo or a sugary drink in their mouths (no swallowing). Those who got the real deal actually had more performance power than the placebo swishers, which might mean that their brains somehow recognized the carbohydrates in the sugary drink and gave their bodies more energy to work with, expecting to be supplemented by the carbs. The mere presence of carbs was enough to have the same energy-boosting effect as ingesting them would have.
I’ve Got the Power! (Well, Maybe.)
Research like this only alludes to the potential existence of a central governor. The theory hasn’t been proven yet, but neither has the C/A model, at least definitively. Speculation still abounds as to why and how people get exhausted when they do. Runners pace themselves without really thinking about it, which shows that the mind is working on a subconscious level, setting limits to how much energy we should exert to prevent going overboard. But if the mind is in control at all times, how does that account for the many examples of athletes’ pushing past their physical threshold and endangering their lives midrace? It seems that the answer lies somewhere in between. Even Noakes agrees that regardless of mental force, physiological forces have the final say.
When you push your body past its limits, be they mentally or physiologically imposed, you can greatly endanger your health. Whether there’s really a secret brain mechanism keeping extra energy on reserve or not, your body demands that you stop exercising for a reason. If it exists, it’s there for emergency situations. So when you feel like collapsing on a run or while biking, at least you can take comfort in knowing that if a cheetah starts chasing you, somewhere deep inside you, there might be just enough power to help you run or ride like the wind.